tag:theconversation.com,2011:/ca/topics/sight-714/articlesSight – The Conversation2023-02-01T16:07:35Ztag:theconversation.com,2011:article/1990132023-02-01T16:07:35Z2023-02-01T16:07:35ZThe true relationship between screens, books and nearsightedness<figure><img src="https://images.theconversation.com/files/507539/original/file-20230201-11-q2h3vk.jpg?ixlib=rb-1.1.0&rect=22%2C0%2C2474%2C1666&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/es/image-photo/kids-reading-book-under-blanket-elder-1071593237">Shutterstock / EvgeniiAnd</a></span></figcaption></figure><p>At one time or another we have surely heard or read that the excessive use of screens is causing an increase in cases of nearsightedness. Moreover, it is said that this relationship is direct, meaning that screens are responsible for the fact that more and more people around the world are nearsighted. Not surprisingly, there are also studies that conclude that <a href="https://www.nature.com/articles/519276a">children who spend more time in front of books or screens develop more nearsightedness than those who do not</a>.</p>
<p>And not only that. We have always assumed that nearsightedness and the use of glasses is directly related to performing tasks that require a special visual effort. Or to very studious people, or to avid life-long book readers.</p>
<p>Since we have recently replaced many of these tasks that involved reading paper with electronic screens, we have shifted the responsibility from one culprit to another.</p>
<p>However, this long-assumed direct relationship has not been scientifically proven. Although it is considered to be true because of the correlation/causation hypothesis, it is important to be careful with these parallels, since correlation does not always imply causation.</p>
<p>Tyler Vigen, a Harvard lawyer, does an excellent job of explaining this. On his website <a href="https://www.tylervigen.com/spurious-correlations">Spurious Correlations</a>, he has been carrying out a statistical experiment with arbitrary data obtained from different sources for years – data that when overlapped on graphs generates some of the most far-fetched correlations. For example, it can be deduced from the data that between 2000 and 2009 there was a correlation between the increase in per capita cheese consumption and deaths caused by becoming entangled in bedsheets. Sounds absurd, right?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/437541/original/file-20211214-13-sf4m87.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/437541/original/file-20211214-13-sf4m87.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/437541/original/file-20211214-13-sf4m87.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=237&fit=crop&dpr=1 600w, https://images.theconversation.com/files/437541/original/file-20211214-13-sf4m87.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=237&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/437541/original/file-20211214-13-sf4m87.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=237&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/437541/original/file-20211214-13-sf4m87.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=297&fit=crop&dpr=1 754w, https://images.theconversation.com/files/437541/original/file-20211214-13-sf4m87.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=297&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/437541/original/file-20211214-13-sf4m87.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=297&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Correlation between per capita cheese consumption and deaths by becoming entangled in bedsheets.</span>
<span class="attribution"><a class="source" href="https://www.tylervigen.com/spurious-correlations">Tyler Vigen / Spurious Correlations</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>What is certain is that the increase in cases of nearsightedness is real and cannot be entirely explained by genetic factors. Therefore, it is necessary to look at environmental factors.</p>
<h2>Accomplices – but not the main culprit</h2>
<p>Are screens – or rather their excessive use – the cause of nearsightedness? The latest studies suggest that they are not directly responsible.</p>
<p>Nearsightedness, which is the difficulty focusing on distant objects, occurs when the eyeball is too long relative to the focusing power of the eye’s cornea and lens. This causes light rays to be directed to a point before the retina.</p>
<p>We are also nearsighted when the cornea, the lens or both are too curved for the length of our eyeball. In some cases, <a href="https://www.mayoclinic.org/diseases-conditions/nearsightedness/symptoms-causes/syc-20375556">all of these factors occur simultaneously</a>.</p>
<p>These anomalies are corrected with lenses that transmit light information to the back of our eye.</p>
<p>The process by which an eye develops nearsightedness is not entirely known, but we do know that for our vision to develop correctly we need to promote and <a href="https://iovs.arvojournals.org/article.aspx?articleid=2772538">practice both near and distance vision</a>.</p>
<p>In this sense, it seems logical to suspect that ongoing exposure to screens from an early age at a time when the eye is still maturing may favour the development of vision of near objects, to the detriment of distance vision. However, there is not enough data to conclude that this causes nearsightedness to occur.</p>
<h2>Eye fatigue</h2>
<p>No one disputes that <a href="https://pubmed.ncbi.nlm.nih.gov/30663136/">excessive use of screens</a> causes “eye fatigue”, also known as “computer syndrome”, which causes redness, stinging and itchy eyes, dry eyes (or conversely, constant tearing), headache, etc. This occurs because when we look at a screen, we blink less (unconsciously), we stare at a specific point for a long time or from an inappropriate angle and we expose ourselves to the excessive brightness of these devices.</p>
<p>What can we do to fight it? Don’t bother <a href="https://onlinelibrary.wiley.com/doi/10.1111/opo.12738">with blue light filters</a> – which are unfairly blamed. The best recommendation to reduce the signs of eye fatigue is to blink frequently and take breaks <a href="https://www.optometrytimes.com/view/deconstructing-20-20-20-rule-digital-eye-strain">following the 20/20/20 rule</a>. In other words, every 20 minutes, take a 20-second break and look at (and try to focus on) an object 20 feet (6 metres) away.</p>
<p>If you look through a window and with light, even better. Why with light? Because it is suspected that one of the possible culprits for the development of nearsightedness is a lack of light.</p>
<h2>Lack of light</h2>
<p>Indeed, it has been proven that children who read a lot, whether on paper or on a digital screen are generally <a href="https://pubmed.ncbi.nlm.nih.gov/26497977/">less exposed to sunlight during the day</a>. And, it has recently been <a href="https://iovs.arvojournals.org/article.aspx?articleid=246623">demonstrated</a> that there is a relationship between nearsightedness and a lack of sunlight.</p>
<p>It seems that solar radiation (especially high-energy radiation, such as blue and <a href="https://pubmed.ncbi.nlm.nih.gov/28063778/">violet light</a>) would stimulate <a href="https://www.pnas.org/content/118/22/e2018840118">dopamine release by retinal amacrine cells</a> (another type of cell other than photoreceptors). This would inhibit the growth of the eye, avoiding the typical elongation that leads to nearsightedness.</p>
<p>There is also experimental evidence that shows that in different animal species, including monkeys, exposure to high-energy violet light could <a href="https://pubmed.ncbi.nlm.nih.gov/22169102/">protect against nearsightedness</a>.</p>
<p>In short, all signs point to the fact that neither books nor electronic devices are directly to blame for the increase in nearsightedness around the world. They have only become accomplices in this phenomenon by keeping children away from sunlight.</p>
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<p class="fine-print"><em><span>Conchi Lillo no recibe salario, ni ejerce labores de consultoría, ni posee acciones, ni recibe financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y ha declarado carecer de vínculos relevantes más allá del cargo académico citado.</span></em></p>Evidence suggests that neither books nor electronic devices are directly to blame for the increase in myopia worldwide. Rather, they enhance this phenomenon by keeping children out of the sunlight.Conchi Lillo, Profesora titular de la Facultad de Biología, investigadora de patologías visuales, Universidad de SalamancaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1931792022-12-08T19:25:39Z2022-12-08T19:25:39Z5 senses? In fact, architects say there are 7 ways we perceive our environments<figure><img src="https://images.theconversation.com/files/499825/original/file-20221208-14230-eo32y0.jpg?ixlib=rb-1.1.0&rect=134%2C291%2C1413%2C855&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Spa bath in a complex designed by architect Peter Zumthor over thermal springs in the Vals Valley, Switzerland. </span> <span class="attribution"><a class="source" href="https://creativecommons.org/licenses/by-nc/2.0/">(Mariano Mantel/Flickr)</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/5-senses-in-fact--architects-say-there-are-7-ways-we-perceive-our-environments" width="100%" height="400"></iframe>
<p>Have you ever wondered why you feel cozy in some places while you feel stunned in others? Think about the last international airport you landed in, or a local coffee shop in your neighbourhood. </p>
<p>How we perceive these places is multifaceted. We often hear that we perceive our environments <a href="https://www.theweeklyjournal.com/business/using-the-five-senses-in-marketing-is-a-must/article_112c8b0e-71a0-11ed-967e-17935054a27f.html">through five senses</a>: sight, smell, touch, sound and taste. But what if there are more senses involved in our perception? </p>
<p>Architects concerned with “the ways we experience things, thus the meanings things have in our experience,” as articulated in the branch of <a href="https://plato.stanford.edu/entries/phenomenology">philosophy known as phenomenology</a> are <a href="https://stoutbooks.com/products/questions-of-perception-phenomenology-of-architecture-1">concerned with a fuller picture of how we perceive our environments</a>.</p>
<h2>More senses</h2>
<p>Beyond the traditional five senses, neuroscientific research also <a href="https://www.sciencedirect.com/topics/neuroscience/proprioception">examines proprioception</a> (sensing your muscles, their location, and their movements) and <a href="https://www.sciencedirect.com/topics/neuroscience/vestibular-system">the vestibular system,</a> which regulates the sense of orientation and balance in space.</p>
<p>Scientists are also examining <a href="https://www.theguardian.com/science/2021/aug/15/the-hidden-sense-shaping-your-wellbeing-interoception">a sense called “interoception” </a> which refers to the perception of sensation from inside
your body. The most commonly experienced one is having butterflies.</p>
<figure class="align-center ">
<img alt="A thin structure appears to be on wooden stilts nestled against sheer rock." src="https://images.theconversation.com/files/499566/original/file-20221207-10117-78sqem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/499566/original/file-20221207-10117-78sqem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=452&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499566/original/file-20221207-10117-78sqem.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=452&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499566/original/file-20221207-10117-78sqem.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=452&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499566/original/file-20221207-10117-78sqem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=567&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499566/original/file-20221207-10117-78sqem.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=567&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499566/original/file-20221207-10117-78sqem.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=567&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Allmannajuvet Zinc Mine Museum in Sauda, southern Norway, designed by Peter Zumthor.</span>
<span class="attribution"><span class="source">(Astrid Westvang/Flickr)</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Phenomenology in architecture</h2>
<p>While architects across cultures and time have long considered the senses and design, the concerns of phenomenology as articulated by philosopher Martin Heidegger were introduced into architecture through <a href="https://doi.org/10.1080/13264821003629279">architect Christian Norberg-Schulz</a> beginning in the early ‘70s.</p>
<p>Architects concerned with phenomenology are interested in how to integrate a renewed fundamental <a href="https://books.google.ca/books/about/Questions_of_Perception.html?id=r7gyAQAAIAAJ&redir_esc=y">understanding of perception</a> to design better buildings. </p>
<p>Phenomenology in architecture refers to a shifting focus on giving users an experience. Beyond <a href="https://books.google.ca/books/about/Genius_Loci.html?id=FlYkAQAAMAAJ&redir_esc=y">Norberg-Schulz</a>, architects <a href="https://doi.org/10.1177/1357034X16676540">Juhani Pallasmaa</a> and <a href="https://www.oasejournal.nl/en/Issues/58/PhenomenologyAndVirtualSpace#035">Alberto Pérez-Gómez</a> have developed this approach, and architects Steven Holl and Peter Zumthor design based on the theories. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/NqlyDCXY9p0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Video about phenomenology in architecture.</span></figcaption>
</figure>
<h2>Thinking about approaching</h2>
<p>Our <a href="https://books.google.ca/books/about/The_Concept_of_Dwelling.html?id=4xxQAAAAMAAJ&redir_esc=y">perception of approaching</a> a building, a city or an object within an environment depends on many factors.</p>
<p>Approaching a city in the middle of the desert is entirely different than approaching a town in a forest. </p>
<p>You can perceive and see a city in a desert in plain sight, and you might perceive the duration it takes to get there longer than it is in reality. When approaching a town in a forest, you will be busy looking around the forest, looking at animals or trees, and experiencing a shorter time than what it took you to get there. </p>
<p>When it comes to buildings, you will first approach them, enter them, and finally start exploring them. From the moment you are on the path of approaching, you start perceiving <a href="https://www.sciencedirect.com/referencework/9780128054093/the-senses-a-comprehensive-reference">with all your different senses</a>. </p>
<figure class="align-center ">
<img alt="A wooden walkway seen extending through water and greenery leading towards a building complex." src="https://images.theconversation.com/files/499565/original/file-20221207-12015-yvtyxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/499565/original/file-20221207-12015-yvtyxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499565/original/file-20221207-12015-yvtyxk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499565/original/file-20221207-12015-yvtyxk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499565/original/file-20221207-12015-yvtyxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499565/original/file-20221207-12015-yvtyxk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499565/original/file-20221207-12015-yvtyxk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Part of the Linked Hybrid complex in Beijing, designed by Steven Holl Architects.</span>
<span class="attribution"><span class="source">(Wojtek Gurak/Flickr)</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Here are some tangible examples:</p>
<p><strong>Touch:</strong> Imagine the moment you are going to touch a front door knob. A wooden door knob will feel different than a steel one.</p>
<p><strong>Smell:</strong> Sometimes, a specific smell can remind you of beautiful memories. It’s the same when it comes to buildings. Everyone can differentiate between the scent of a clean vacant space and a cottage in the woods.</p>
<p><strong>Sound:</strong> You can get different feelings of space by just perceiving it with your ears. Compare a room with ceramic tiles where you hear shoes clacking along the floor and walking on a wooden floor where you hear the wooden floors. </p>
<figure class="align-right ">
<img alt="Image of a house in the distance with a light on in the darkness and snow falling around it." src="https://images.theconversation.com/files/499814/original/file-20221208-14351-65pkn0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/499814/original/file-20221208-14351-65pkn0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499814/original/file-20221208-14351-65pkn0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499814/original/file-20221208-14351-65pkn0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499814/original/file-20221208-14351-65pkn0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499814/original/file-20221208-14351-65pkn0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499814/original/file-20221208-14351-65pkn0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Do you see, hear or smell a fire?</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p><strong>Sight:</strong> All of us have seen pictures showing a small house in the distance where a small light is on on a snowy day. That tiny light on a snowy day can be a fireplace we can feel just by seeing it in the distance.</p>
<p><strong>Taste:</strong> It might be hard to link taste to architecture, but architecture can be a stimulus for taste. Specific colours and details can stimulate taste. For instance, marble might give you <a href="https://www.theguardian.com/lifeandstyle/wordofmouth/2013/mar/12/how-taste-different-colours">a particular sensation of taste</a>.</p>
<p><strong>Vestibular (movement) and proprioception (body position):</strong> These two senses are the foundation for orienting yourself in a space and being self-conscious within an environment.</p>
<h2>Stimuli in our environments</h2>
<p>It’s important to also consider what <a href="https://www.stevenholl.com/">Steven Holl</a>, a New York-based architect, believes <a href="https://books.google.ca/books/about/Questions_of_Perception.html?id=r7gyAQAAIAAJ&redir_esc=y">are the 11 stimuli in our environments that affect our perception</a>.</p>
<p>1) An object is perceived within its surrounding. If you have a flower in front of your windows, the background will also play an important role in perceiving it and your impression of the flower. </p>
<p>2) Our perception is a series of frames from our environment that changes with our every single move.</p>
<p>3) <a href="https://books.google.bg/books/about/Colors.html?id=RRklvgAACAAJ&redir_esc=y">Colours</a> have an important role in our perception. </p>
<p>4) Light and shadows can give us different feelings.</p>
<p>5) Night and day can yield completely different experiences.</p>
<figure class="align-center ">
<img alt="A white rectangular building seen reflected into water beside it." src="https://images.theconversation.com/files/499564/original/file-20221207-26-xuglf3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/499564/original/file-20221207-26-xuglf3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=379&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499564/original/file-20221207-26-xuglf3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=379&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499564/original/file-20221207-26-xuglf3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=379&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499564/original/file-20221207-26-xuglf3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=476&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499564/original/file-20221207-26-xuglf3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=476&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499564/original/file-20221207-26-xuglf3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=476&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Nelson-Atkins Museum of Art, Kansas City, Mo., designed by Steven Holl Architects.</span>
<span class="attribution"><span class="source">(Dean Hochman/Flickr)</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>6) Perception of time is not linear and depends on many different factors.</p>
<p>7) Water is a reflection of its surrounding environment.</p>
<p>8) Sound helps to perceive our environment. Imagine measuring the depth of a room by echoing.</p>
<p>9) Details in design are an essential factor that can have different impacts. A person can easily differentiate the feeling and taste of natural wood from an artificial one.</p>
<p>10) <a href="https://www.routledge.com/Proportion-Science-Philosophy-Architecture/Padovan/p/book/9780419227809">Proportions and scales</a> are other critical factors in perceiving our environment. If a building is too big in scale, it can give you a feeling of being stunned, while a lower ceiling height can make you feel cozy.</p>
<p>11) Ideas are vital in designing buildings as they can give people different experiences.</p>
<p>Accordingly, if you want to create a cozy coffee shop, you design it with low lights, warm colors, a nice ambient sound. An idea at the centre influences details with furniture and interiors, ceiling height and everything else.</p>
<p>Phenomenology in architecture helps create better environments based on how humans perceive their surroundings. Whether you are planning to go to a local restaurant or an exhibition, you can now think about how your experiences in a space are related to your sense perception.</p><img src="https://counter.theconversation.com/content/193179/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Farzam Sepanta does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Stimuli such as light and shadow and our perception of the passage of time matter to architects interested in the branch of philosophy known as phenomenology.Farzam Sepanta, PhD Candidate, Building Engineering, Carleton UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1775832022-03-10T11:28:40Z2022-03-10T11:28:40ZIf you love ASMR you might be more sensitive, our research finds<p>Do you ever experience a tingling sensation in your scalp when someone whispers? </p>
<p>If you recognise that feeling, then you may well be acquainted with the phenomenon that’s gathered millions of followers over the last few years, and has been dubbed “autonomous sensory meridian response” (<a href="https://theasmr.com/what-is-asmr-meaning/">ASMR</a>). </p>
<p>For those of you who haven’t heard of ASMR, it’s a relaxing head-orientated tingling sensation that some people experience in response to various sensory “triggers”. It could be watching someone brush hair, or fold laundry with care and expertise or certain sounds like whispering or tapping. And in everyday life, one of the most common triggers is actually soft touch – like stroking someone’s arm or tracing fingers on the back.</p>
<p>Some people <a href="https://www.ncbi.nlm.nih.gov/books/NBK453209/#:%7E:text=Their%20results%20indicated%20that%20the,effect%20of%20ASMR%20on%20mood">report experiencing</a> ASMR for “as long as they can remember” – but the explosion of <a href="https://ahrefs.com/blog/top-youtube-searches/">online ASMR videos</a> is allowing people to tap into the sensation on-demand rather than having to wait for it to happen as they go about their daily lives. And many people (even those that don’t experience ASMR tingling) may use them for relaxation and sleep. </p>
<p>But an intriguing question that remains unanswered is why only some people experience ASMR tingling.</p>
<p>We recently conducted <a href="https://www.sciencedirect.com/science/article/abs/pii/S0092656621001203">a study</a> which goes some way towards answering this question. It seems that people who experience ASMR have heightened sensory sensitivity – that is, they are more sensitive to what’s going on around them, and inside them. Here’s how we found out, and what it means.</p>
<h2>Sensitivity explained</h2>
<p>We all differ in <a href="https://www.tandfonline.com/doi/pdf/10.1080/17588928.2018.1557131?casa_token=yRKIJyIeo1AAAAAA:6yggeDHHK-H9JzT0ewFypPEfwhuVR-WymeFJOt18QqN5jAZkCt-hq2FMzCvokdC4pSWp-UkEkV9HsQ">how sensitive</a> we are to information from our five external senses (touch, sight, hearing, smell and taste). If you’re highly sensitive to external input you might be disgusted at the strong smell of an aftershave as you pass someone in the street, for example. </p>
<p>We also vary in sensitivity to our body’s internal state, such as whether we’re feeling hungry or cold. </p>
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Read more:
<a href="https://theconversation.com/differences-in-how-men-and-women-perceive-internal-body-signals-could-have-implications-for-mental-health-172917">Differences in how men and women perceive internal body signals could have implications for mental health</a>
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<p>So, to investigate whether people with ASMR are more “sensitive”, we tested participants using the most commonly used measures of internal and external sensory sensitivity. The <a href="https://www.pearsonclinical.co.uk/store/ukassessments/en/Store/Professional-Assessments/Motor-Sensory/Adolescent-Adult-Sensory-Profile/p/P100009054.html">adult sensory profile</a>, for example, asked participants to rate their response in numerous situations (such as how well they work with background noise or whether they startle easily at unexpected or loud noises). </p>
<p>We also assessed whether participants experience ASMR when exposed to 16 common triggers, and if so, the strength of their ASMR response and how they experienced it.</p>
<h2>Sensitivity links to ASMR</h2>
<p>It turned out that people who experience ASMR showed much higher levels of sensory sensitivity than people without ASMR.</p>
<p>They report hypersensitivity and negative responses to external stimuli such as noise and movement, and are easily overstimulated by their environment. They also show higher levels of body awareness and greater sensitivity to internal bodily sensations – noticing how their body changes when they feel happy, for example.</p>
<p>And the strength of their ASMR response was also associated with heightened external sensitivity and greater control over their attention towards their body and emotional state. </p>
<p>We think that the concept of the “highly sensitive person” (<a href="https://www.sciencedirect.com/science/article/pii/S0149763418306250">HSP</a>) may be central for differentiating ASMR responders from non-responders. </p>
<p>Using a <a href="https://sensitivityresearch.com/about-sensitivity/">flower metaphor</a>, developed by researchers to distinguish between people who have different levels of sensitivity – both internal and to the external social environment, such as people and visual stimuli – our study found that 56% of ASMR responders were categorised as highly sensitive “orchids” (who do well in ideal conditions but badly in poor conditions) with only 12% categorised as the environmentally resilient “dandelions”. The remainder were “tulips” who lie somewhere in between. </p>
<p>This contrasts with other studies suggesting that highly sensitive orchids usually make up around <a href="https://www.nature.com/articles/s41398-017-0090-6">30% of the population</a>.</p>
<p>As people with ASMR are more likely to be classified as highly sensitive, that might go some way towards explaining why ASMR has been linked to empathy. HSPs process social information more deeply which is <a href="https://onlinelibrary.wiley.com/doi/pdf/10.1002/brb3.242">thought to underpin</a> their ability to be more attuned and responsive to others’ emotions and needs. Future research may find similar enhanced social and emotional processing abilities in people with ASMR, but this needs to be properly investigated. </p>
<p>ASMR has been shown to enhance feelings of <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0196645">social connection</a> and the strongest ASMR triggers often simulate situations involving interpersonal closeness, intimacy, and touch. It may be that people who experience ASMR also derive more emotional benefit from social interactions. One fascinating possibility is that the tingling of ASMR reflects the ability to simulate <a href="https://www.sciencedirect.com/science/article/abs/pii/S0149763408001723?casa_token=2hTSpDq2tc0AAAAA:Hpy-wHdfNID3u6-JOk_SVflJQ02lR9mdSmRqrQiXJDa1J4_Sc0erl5jjGDLmXpffj-6uEouKFnw">social touch</a> and its benefits – such as stress reduction and mental well-being – from non-tactile stimuli. </p>
<p>There is one intriguing paradox: the same people who experience and enjoy ASMR triggers can often also be repulsed by the same sounds in different circumstances. ASMR-sensitive people have <a href="https://peerj.com/articles/3846/">elevated levels</a> of misophonia (a condition describing aversive and <a href="https://pubmed.ncbi.nlm.nih.gov/28561277/">angry feelings</a> in response to certain sounds, such as tapping, chewing or lip smacking), with 43% experiencing it. </p>
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<strong>
Read more:
<a href="https://theconversation.com/asmr-what-we-know-so-far-about-this-unique-brain-phenomenon-and-what-we-dont-135106">ASMR: what we know so far about this unique brain phenomenon – and what we don't</a>
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<p>If the same trigger sounds elicit opposite emotional reactions in the same people, then this could mean that there isn’t anything inherently pleasant or unpleasant about the sounds themselves. </p>
<p>Our findings suggest that one reason for this seemingly odd co-occurrence might be because both ASMR and misophonia are underlined by increased sensory sensitivity, especially to sound. The situation, and how the sensory information is translated into an emotional response, might then determine whether the same sound is evaluated as positive or negative by the same person. Being sensitive has many benefits – but as with all things in life, it has its complications too.</p><img src="https://counter.theconversation.com/content/177583/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Giulia Poerio does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It’s intriguing how some people experience ASMR while others don’t - our latest research suggests that many ASMR responders are highly sensitive “orchids”.Giulia Poerio, Associate lecturer, University of EssexLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1579162021-04-18T12:51:50Z2021-04-18T12:51:50ZCurious Kids: What do blind people experience in their dreams?<figure><img src="https://images.theconversation.com/files/394320/original/file-20210409-21-1mj6tit.jpg?ixlib=rb-1.1.0&rect=36%2C18%2C5970%2C3989&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The dreams of a person without sight since birth can be just as vivid and imaginative as those of someone with normal vision.</span> <span class="attribution"><span class="source">(Unsplash)</span></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>Curious Kids is a series for children of all ages. Have a question you’d like an expert to answer? Send it to <a href="mailto:curiouskidscanada@theconversation.com">CuriousKidsCanada@theconversation.com</a>.</em></p>
<blockquote>
<p>What do blind people experience in their dreams? — James</p>
</blockquote>
<p>Humans are extremely visual. Nearly <a href="https://www.rochester.edu/pr/Review/V74N4/0402_brainscience.html">half of our brain is devoted to processing visual information</a>. Most of the brain networks responsible for providing vision <a href="https://faculty.washington.edu/chudler/plast.html">are established early in life</a>.</p>
<p>This means that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3722610/">from about the time of birth we begin our lifelong collection of experiences and memories</a> that strongly rely on vision. </p>
<p>Throughout life, we associate most of our interactions with visual images rather than with experiences from our other senses such as hearing or smell. </p>
<p>For those of us with normal vision, <a href="https://doi.org/10.1016/j.tics.2009.12.001">dreams are full of the visual images we experience during our waking life</a>. To understand what blind people experience in their dreams, we must distinguish the experiences of those who were blind at birth from those that became blind later in life. </p>
<h2>Just as vivid and imaginative</h2>
<p>Humans born without sight are not able to collect visual experiences, so <a href="https://www.scientificamerican.com/article/superpowers-for-the-blind-and-deaf/">they understand the world entirely through their other senses</a>. As a result, people with blindness at birth develop an amazing ability to understand the world through the collection of experiences and memories that come from these non-visual senses. </p>
<figure class="align-center ">
<img alt="Woman waking up in bed" src="https://images.theconversation.com/files/394333/original/file-20210409-21-1n9k6kp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/394333/original/file-20210409-21-1n9k6kp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/394333/original/file-20210409-21-1n9k6kp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/394333/original/file-20210409-21-1n9k6kp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/394333/original/file-20210409-21-1n9k6kp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/394333/original/file-20210409-21-1n9k6kp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/394333/original/file-20210409-21-1n9k6kp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The dreams of people who develop blindness later in life become less visual as their time without vision increases.</span>
<span class="attribution"><span class="source">(Kinga Cichewicz/Unsplash)</span></span>
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</figure>
<p>The dreams of a person who has been without sight since birth can be just as vivid and imaginative as those of someone with normal vision. They are unique, however, because their <a href="https://wtamu.edu/%7Ecbaird/sq/2020/02/11/do-blind-people-dream-in-visual-images/">dreams are constructed from the non-visual experiences and memories they have collected</a>. </p>
<p>While a person with normal vision will dream about a familiar friend using visual memories of shape, lighting and colour, a blind person will associate the same friend with a unique combination of experiences from their non-visual senses that act to represent that friend. </p>
<p>In other words, people blind at birth have similar overall dreaming experiences but <a href="https://www.bbc.com/news/blogs-ouch-28853788">they do not dream in pictures</a>. </p>
<p>The dream experience of a person who lost vision later in life is very different than someone who never had vision. People that lose vision later in life had the ability to collect many visual experiences that can appear in their dreams and in a manner very similar to a sighted person. </p>
<p>Interestingly — and perhaps expected — <a href="https://doi.org/10.1016/j.sleep.2013.12.008">the dreams of people who develop blindness later in life become less visual as their time without vision increases</a> and as they collect more experiences without vision. </p>
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<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidscanada@theconversation.com">CuriousKidsCanada@theconversation.com</a>. Please tell us your name, age and the city where you live.</em>
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<hr><img src="https://counter.theconversation.com/content/157916/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kevin Duffy receives funding from the Natural Sciences and Engineering Research Council of Canada, and from the Canadian Institutes of Health Research. </span></em></p>A curious kid asks: what do blind people experience in their dreams?Kevin Duffy, Professor, Department of Psychology and Neuroscience, Dalhousie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1452762020-09-03T12:40:13Z2020-09-03T12:40:13Z‘Curing blindness’: why we need a new perspective on sight rehabilitation<figure><img src="https://images.theconversation.com/files/356355/original/file-20200903-16-1ifm79u.jpg?ixlib=rb-1.1.0&rect=50%2C0%2C5637%2C3755&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Many blind people want sight rehabilitation technologies to increase their independence.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/blind-visually-impaired-childkidtoddlerpreschoolerboy-walking-through-1192950880">Tracy Spohn/ Shutterstock</a></span></figcaption></figure><p>In a society <a href="https://www.smh.com.au/opinion/the-challenges-of-using-technology-when-youre-blind-20170517-gw6jp5.html">focused on visual communication</a>, being blind can have severe disadvantages. In fact, research shows blind people are at <a href="https://www.rnib.org.uk/sites/default/files/Employment%20status%20and%20sight%20loss%202017.pdf">higher risk of unemployment</a>, <a href="https://hqlo.biomedcentral.com/articles/10.1186/s12955-019-1096-y">social isolation, and lower quality of life</a> than sighted people. Given the huge impact blindness has on society and those without vision, the drive to find a “cure” for blindness has become a profitable market. </p>
<p>Many new, cutting-edge developments that “<a href="https://www.nationalgeographic.com/magazine/2016/09/blindness-treatment-medical-science-cures/">cure blindness</a>” build on promises they often <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1772467/">cannot keep</a>, leaving many blind people and their families feeling disappointed and disillusioned. But what does “curing blindness” actually mean – and how can it be achieved in a way that it most benefits the blind person? </p>
<p>When we think of “curing blindness”, we often think about <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6350159/">restoring the lost sense</a> – for example, through vision-enhancing technology, bionic eyes, or gene therapy. This is because we typically treat an impaired sense by focusing on the damaged sensory organ. But while our eyes deliver the sensory input, by transforming light into electrical impulses that our brains can use, most visual perception <a href="https://theconversation.com/how-do-our-brains-reconstruct-the-visual-world-49276">happens in the brain</a>. </p>
<p>The perception of a visual object, a coffee cup, say, is created across different <a href="https://www.youtube.com/watch?v=P-7mO2FhaVE">hierarchical levels</a> in the visual cortex of our brain. Simple two-dimensional features, such as edges and colours, are combined into more complex shapes, which are in turn combined into the perception of whole objects, like our coffee cup. Across these different levels, our previous visual and non-visual experiences strongly influence <a href="http://people.psych.cornell.edu/%7Ejec7/pubs/ostrovskyetal.pdf">how we perceive</a> the final object.</p>
<figure class="align-center ">
<img alt="Steaming coffee cup on table." src="https://images.theconversation.com/files/356352/original/file-20200903-24-1vtyc9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/356352/original/file-20200903-24-1vtyc9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/356352/original/file-20200903-24-1vtyc9y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/356352/original/file-20200903-24-1vtyc9y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/356352/original/file-20200903-24-1vtyc9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/356352/original/file-20200903-24-1vtyc9y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/356352/original/file-20200903-24-1vtyc9y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Most of what we ‘see’ happens in the brain itself.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/lighting-window-hot-white-coffee-cup-348244271">NOPPHARAT42896395/ Shutterstock</a></span>
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<p>Because of the complex nature of visual perception, sight is incredibly difficult to restore, and achieving a satisfactory level of visual function is not easy. Despite significant advances in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6350159/">visual restoration technology</a>, even the best visual implants typically only allow visual acuity of 1/60, which is technically still classed as <a href="https://www.who.int/news-room/fact-sheets/detail/blindness-and-visual-impairment">blindness</a> by the World Health Organization. While this minimal form of light perception is already great progress, it’s <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0134369">not enough</a> to allow a person to live independently. </p>
<p>While every blind person has their own ideas of what sight rehabilitation should do for them, what resonates with most is the aim to <a href="https://theconversation.com/to-provide-eyes-or-not-to-provide-eyes-36408">increase independence</a> by allowing blind people to gain more access to visual information. </p>
<p>But does the brain need vision for that? Not necessarily. This is why we need to adopt a different perspective on sensory rehabilitation – one that views vision as part of a greater multisensory experience. After all, perception is rarely based on one sense alone but on a combination of multisensory experiences in which our senses influence each other. </p>
<h2>Multisensory perspective</h2>
<p>The brain has the remarkable ability to compensate for sensory loss by <a href="https://theconversation.com/do-blind-people-have-better-hearing-102282">reorganizing</a> how it processes information. In fact, the brain learns to perceive through the sensory experiences it makes during childhood. If all sensory experience is non-visual, perception will develop around these experiences. So if a person was born without sight, or lost their sight early on in childhood, their perception will develop around the non-visual senses.</p>
<p>This is why, on some tasks, blind people perform better than sighted people, while, on other tasks, they may perform worse. This dichotomy seems to underlie a simple principle: is the sense that is typically used for this task the <a href="https://brill.com/view/journals/msr/28/1-2/article-p71_5.xml">best suited</a> for accessing this information? For example, we are well able to locate a buzzing phone using either our vision or hearing. In this case, more experience finding objects through sound will lead to <a href="https://academic.oup.com/brain/article/137/1/6/365182">superior performance in blind people</a> when only hearing is used. However, given that our vision is much better suited to perceiving people’s faces, blind people usually perform worse than sighted people when <a href="https://pubmed.ncbi.nlm.nih.gov/23399994/">recognising other’s faces through touch</a>.</p>
<p>We know that the brain learns best about the environment when it can access the same information <a href="https://faculty.ucr.edu/%7Easeitz/pubs/Shams_Seitz08.pdf">through multiple senses</a>. This benefits our perception by <a href="https://www.semanticscholar.org/paper/Merging-the-senses-into-a-robust-percept-Ernst-B%C3%BClthoff/66ed3eaa6ae8e7a0e48c268d579c890a2968c061">enhancing accuracy and precision</a>. But if we want to make use of this perceptual benefit in vision rehabilitation, we need to know whether the blind brain actually learned to generate it. </p>
<p>It turns out that this <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/desc.13001">depends on the age</a> a person goes blind. Blindness before the age of eight or nine years influences how touch and hearing are used together to estimate object size. But blindness after this age impairs the ability to enhance perception through multisensory combination. </p>
<p>So what does that mean for sensory rehabilitation? We know that there’s not one best solution for all, but we also know that the age of blindness-onset can provide important clues. If a person has been blind since birth or early childhood, the brain does not know how to process visual information, so vision restoration may not bring much benefit. If, however, sight was lost later in life, the brain is best wired to perceive its surroundings through vision.</p>
<p>But there’s still good news for the congenitally and early blind: the enhanced perceptual abilities in the remaining senses can be used to <a href="https://www.sciencedirect.com/science/article/pii/S0149763413002765">substitute vision</a>. In fact, visual information does not have to be taken up through the eyes – it can also reach the brain through our <a href="https://theconversation.com/camera-mobile-headphones-the-low-cost-set-up-that-can-help-blind-people-see-35936">other senses</a>. In order for that to happen, it first needs to be translated into a different “sensory language”. For example, visual information can be directly <a href="https://www.seeingwithsound.com/">translated into sound</a>. Through training, the brain then learns to use this <a href="https://www.frontiersin.org/articles/10.3389/fpsyg.2020.01443/full">new sensory language</a>, opening up the visual world through the use of another sense. </p>
<p>While sensory restoration advancements have come a long way, we are still far from an optimal solution that allows blind people to access visual information and equally partake in society. By realising that perception depends on individual experiences, we can better develop solutions that will most benefit each person – whether that aims to restore their sight, or seeks to use their other senses instead.</p><img src="https://counter.theconversation.com/content/145276/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Meike Scheller's work has been carried out at the University of Bath with support from the University, the British Academy, and the NIHR. </span></em></p>Perception is multisensory.Meike Scheller, Research Fellow, University of AberdeenLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1363212020-04-27T12:12:08Z2020-04-27T12:12:08ZWelcome to your sensory revolution, thanks to the pandemic<figure><img src="https://images.theconversation.com/files/330391/original/file-20200424-163062-1amz996.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">No smell, no touch: People line up in Prague, Czech Republic, to get tested for the coronavirus. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/people-line-up-to-get-tested-for-the-coronavirus-in-prague-news-photo/1210703825?adppopup=true">Getty/Gabriel Kuchta</a></span></figcaption></figure><p>The way we see, hear, taste, touch and smell may never be the same again.</p>
<p>Courtesy of COVID-19, we are undergoing a sensory revolution. All of the senses have been affected by the coronavirus pandemic – not because the senses themselves have changed, but because the context and environment in which we sense has been profoundly altered.</p>
<p>Sensory historians <a href="https://www.sc.edu/study/colleges_schools/artsandsciences/history/our_people/directory/smith_m_mark.php">like myself</a>, who study the ways in which people in the past used their senses to understand and navigate their worlds, find that sensory shifts and perceptions tended to happen very slowly, measured in decades and centuries, <a href="https://www.bloomsbury.com/uk/sensory-history-9781845204150/">not in mere weeks and months</a>.</p>
<p>The shift that is happening now is unprecedented.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/jwClyd2lHWo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Emptiness is the symbol of life in the time of coronavirus.</span></figcaption>
</figure>
<h2>Sensory hierarchy</h2>
<p>The very idea that there are only five distinct senses took ages to mature, gaining credence in the Enlightenment. This period not only discounted erstwhile senses – such as the sense of “intuition” – but arranged the five senses into a distinctive hierarchy.</p>
<p>The Age of Reason empowered the eye as the sense of truth; seeing was believing, said most thinkers in the 1700s. Sight was followed by hearing, understood as more refined than the so-called lower or proximate senses. Those are smell, taste and touch, senses that had once been held in high esteem in the ancient and medieval worlds, but which lost their currency and <a href="https://www.bloomsbury.com/uk/sensory-history-9781845204150/">became more associated with the animal senses</a>.</p>
<p>These changes took time. Seeing was believing by about 1800, but it had taken centuries for the original iteration of the phrase, “seeing is believing, but feeling’s the truth,” to lose its tactile component.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The sight, sound and smell of traffic have disappeared from New York City.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/the-view-looking-east-down-an-empty-street-amid-the-news-photo/1220494566?adppopup=true">Getty/Alexi Rosenfeld</a></span>
</figcaption>
</figure>
<h2>Sensing changes</h2>
<p>With the sensory hierarchy intact, the 19th century ushered in some profound and long-term changes in how people used and understood their senses.</p>
<p>Olfaction offers a good example. Western noses became more refined, more sensitive and more alert to noxious smells. Rank and fetid smells gave way to a world that valued pleasant and deodorized smells. Washing and bathing became more popular, as did the use of perfumes and scents. Noses that could detect the difference were applauded. This olfactory <a href="https://www.google.com/books/edition/The_Foul_and_the_Fragrant/LI1M4sLcvPAC?hl=en&gbpv=1&dq=alain+corbin+fould+and+the+fragrant&printsec=frontcover">evolution in smells and habits of smelling took about a century</a>. </p>
<p>Now think of the sensory changes that have taken place in just a matter of months.</p>
<h2>New sights, louder sounds</h2>
<p>Once-trusty eyes betray us in the face of an invisible enemy. Seeing is no longer believing. Those who appear perfectly healthy <a href="https://www.npr.org/sections/goatsandsoda/2020/04/13/831883560/can-a-coronavirus-patient-who-isnt-showing-symptoms-infect-others">may be unknowing disease transmitters</a>.</p>
<p>But if the cause of COVID-19 is invisible, its effects are emphatically not. Desolate city streets are new sights; the absence of airplane contrails strikes many as almost primordial; masks render <a href="https://www.youtube.com/watch?v=jwClyd2lHWo">once-familiar faces unrecognizable</a>. </p>
<p>Soundscapes have changed, as have habits of listening. <a href="https://www.bloomberg.com/news/articles/2020-04-22/how-silent-spreaders-make-coronavirus-hard-to-beat-quicktake">Coronavirus spreaders are sometimes described as “silent.</a>” Many urban dwellers hear less traffic and formerly smothered sounds – <a href="https://www.nbcwashington.com/news/coronavirus/hopeful-birdsong-foreboding-sirens-a-pandemic-in-sound/2265854/">such as birdsong</a> – now can be heard. </p>
<p>The world is in some ways a much quieter place. Seismic sensors are picking up activity that used to be drowned out <a href="https://gizmodo.com/seismometers-worldwide-detect-decrease-in-human-activit-1842526497">by the activity of cities</a>. None of these sounds is new, but the effects of COVID-19 have reconfigured habits of listening and thresholds of hearing. Human voices are louder because there are <a href="https://www.irishtimes.com/news/ireland/irish-news/coronavirus-birdsong-seems-louder-and-the-ravens-are-more-relaxed-1.4231725">no whispers at six feet</a>.</p>
<p>The sense of smell has been hit hard. To breathe, after all, is to smell – if you can. Anosmia – the loss of the sense of smell – <a href="https://scopeblog.stanford.edu/2020/04/17/how-viruses-like-the-coronavirus-can-steal-our-sense-of-smell/">is an early sign of infection</a>. </p>
<p>Even if we keep our sense of smell, we now pause before inhaling, lest we <a href="https://economictimes.indiatimes.com/news/international/world-news/lost-sense-of-smell-may-be-peculiar-clue-to-coronavirus-infection/articleshow/74767666.cms">breathe in an enemy we cannot see</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Food tastes different if you can’t eat it until you get it home.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/woman-wearing-gloves-and-a-scarf-can-be-seen-in-the-news-photo/1219591346?adppopup=true">Getty/Alexi Rosenfeld</a></span>
</figcaption>
</figure>
<p>Taste is no longer as easily sated, and palates are rearranged. Restaurants still cater, but in takeout fashion and with less variety. Hot food once served in the restaurant is colder and less palatable after it’s transported to the more distant dining room table. Clammy hamburgers on soggy buns served with limp french fries, anyone? Grocery stores now ration once taken-for-granted staples, <a href="https://www.bloomberg.com/news/articles/2020-04-21/food-rationing-is-new-reality-for-buyers-once-spoiled-for-choice">notably eggs, milk and meat</a>.</p>
<p>Touch is the obvious sensory casualty in all of this. Centuries of handshaking habits have evaporated; high fives are gone. Outside of families, hugs, kisses and nuzzles have <a href="https://www.allure.com/story/covid-19-skin-hunger-lack-of-touch">all been lost with the fear of infection</a>.</p>
<h2>No guide</h2>
<p>In sensory terms, there has been nothing like this. </p>
<p>Even the violence done to the senses by wars, hurricanes, tornadoes and earthquakes is <a href="https://global.oup.com/academic/product/the-smell-of-battle-the-taste-of-siege-9780190658526?lang=en&cc=us;%20https://books.google.com/books/about/Camille_1969.html?id=CBcRmQEACAAJ">modest in scale and scope compared to this sensory revolution</a>. </p>
<p>Possible legacies, short-term or long, are hard to fathom. Beyond the deaths, the long-term effects of this pandemic will likely be in words and culture, not eternal lockdowns. Sensory and rhetorical turns of phrases will change. The results will not be even. Thanks to virtual communication, “See ya” and “I hear ya” should remain stable, but “staying in touch” and “getting a grip” could go the way of the sensory dinosaur.</p>
<p>But if normalcy eludes us? </p>
<p>A whole new world of sensory engagement will emerge, and it could be terrifying. Our soundscape could be civil strife, punctuated with the <a href="https://www.dailymail.co.uk/news/article-8235307/Riots-break-suburbs-Paris-amid-anger-French-police-heavy-handedness-lockdown.html">smell of tear gas</a> and the <a href="https://www.theguardian.com/world/2020/mar/28/south-africa-police-rubber-bullets-shoppers-covid-19-lockdown">resounding sting of rubber bullets on flesh</a>.</p>
<p>There is no sensory past that can guide us here. It is a genuine revolution of the senses. And it stinks.</p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/136321/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark M. Smith does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>All of the senses have been affected by the coronavirus pandemic, not because the senses have changed, but because the world has, writes a sensory historian.Mark M. Smith, Carolina Distinguished Professor of History, University of South CarolinaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1359102020-04-17T12:10:34Z2020-04-17T12:10:34ZWhat’s lost when we’re too afraid to touch the world around us?<figure><img src="https://images.theconversation.com/files/327759/original/file-20200414-117578-p28xy.jpg?ixlib=rb-1.1.0&rect=4%2C9%2C3290%2C2158&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">We touch, therefore we know.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/24077861-royalty-free-image/87516258?adppopup=true">Jupiterimages/Getty Images</a></span></figcaption></figure><p>During one of my daily walks with my toddler, when we passed his favorite playground, I noticed a new sign warning that the coronavirus survives on all kinds of surfaces and that we should no longer use the playground. Since then, I’ve taken great pains to prevent him from touching things. </p>
<p>This hasn’t been easy. He loves to squeeze bike racks and graze tree trunks, jostle bushes and knock on picnic tables. He likes to run his fingers against bars around a swimming pool and pet the chickens at the neighborhood coop. </p>
<p>Whenever I bat his hand away or try to distract him from potentially absorbing these dreaded, invisible germs, I wonder: What’s being lost? How can he possibly indulge his curiosity and learn about the world without his sense of touch? </p>
<p>I find myself thinking about <a href="https://plato.stanford.edu/entries/herder/">Johann Gottfried Herder</a>, an 18th-century German philosopher who published a treatise on the sense of touch in 1778. </p>
<p>“Go into a nursery and see how the young child who is constantly gathering experience reaches out, grasping, lifting, weighing, touching and measuring things,” <a href="https://www.press.uchicago.edu/ucp/books/book/chicago/S/bo3614360.html">he wrote</a>. In doing so, the child acquires “the most primary and necessary concepts, such as body, shape, size, space and distance.” </p>
<p>During the European Enlightenment, sight was considered by many to be the most important sense because it could perceive light, and light also symbolized scientific fact and philosophical truth. However, some thinkers, such as Herder and <a href="https://plato.stanford.edu/entries/diderot/">Denis Diderot</a>, questioned sight’s predominance. Herder <a href="https://www.press.uchicago.edu/ucp/books/book/chicago/S/bo3614360.html">writes that</a> “sight reveals merely shapes, but touch alone reveals bodies: that everything that has form is known only through the sense of touch and that sight reveals only … surfaces exposed to light.” </p>
<p>To Herder, our knowledge of the world – our relentless curiosity – is fundamentally transmitted and satiated through our skin. Herder argues that blind people are, in fact, privileged; they’re able to explore via touch without distraction and are “able to develop concepts of the properties of bodies that are far more complete than those acquired by the sighted.” </p>
<p>For Herder, touch was the only way to understand the form of things and grasp the shape of bodies. Herder changes René Descartes’ statement “I think, therefore I am” and claims: We touch, therefore we know. We touch, therefore we are. </p>
<p>Herder was onto something. Centuries later, neuroscientists like David Linden have been able to map out the power of touch – the first sense, he notes in his book
“<a href="https://books.google.com/books/about/Touch.html?id=S8QcBAAAQBAJ">Touch: The Science of Hand, Heart, and Mind</a>,” to develop in utero.</p>
<p>Linden writes that our skin is a social organ that cultivates cooperation, improves health and enhances development. He points to <a href="https://psycnet.apa.org/record/2010-22093-017">research</a> showing that celebratory hugging among professional basketball players improves team performance, that premature babies <a href="https://doi.org/10.12968/hmed.2012.73.5.278">are more likely to survive</a> if they’re regularly held by their parents instead of being kept solely in incubators and that children severely deprived of touch <a href="https://books.google.com/books/about/Touch.html?id=S8QcBAAAQBAJ">end up with more developmental problems</a>.</p>
<p>During this period of social distancing, what sort of void has been created? In our social lives, touches are often subtle and brief – a quick handshake or hug. Yet it seems as though these brief encounters contribute mightily to our emotional well-being.</p>
<p>As a professor, I know it’s been a huge advantage to have digital technology that enables remote learning. But my students are missing out on the little touches, intentional or accidental, from their friends and classmates, whether it’s in the classroom, in dining halls or in their dorms.</p>
<p>Perhaps not surprisingly, touch plays a bigger role in some cultures than in others. Psychologist Sidney Jourard <a href="https://doi.org/10.1111/j.2044-8260.1966.tb00978.x">observed the behavior</a> of Puerto Ricans in a San Juan coffee shop and found that they touched one another an average of 180 times per hour. I wonder how they’re handling social distancing. Residents of Gainesville, Florida, are probably having an easier time; Jourard found they only touched twice per hour in a coffee shop.</p>
<p>Social distancing is crucial. But I’m already pining for the day when we can all engage with the world unimpeded, touching without anxiety or hesitation.</p>
<p>We’re more impoverished without it.</p>
<p>[<em>Insight, in your inbox each day.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=insight">You can get it with The Conversation’s email newsletter</a>.]</p><img src="https://counter.theconversation.com/content/135910/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chunjie Zhang receives research funding from the University of California, Davis. </span></em></p>With dreaded, invisible germs lurking on surfaces and in people, our surroundings are seen as a minefield – and we end up dulling one of our most valuable senses.Chunjie Zhang, Associate Professor of German, University of California, DavisLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1249442019-10-14T14:57:32Z2019-10-14T14:57:32ZCurious Kids: how can we see what we are imagining as well as what’s in front of us?<figure><img src="https://images.theconversation.com/files/296890/original/file-20191014-135501-1r4zgav.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6016%2C4016&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">You might be daydreaming, but your brain is hard at work.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/muslim-woman-holding-pen-handput-wireless-1503771215?src=AqmA4eYQgoN-AJNsjbJ_1A-4-27">February_Love/Shutterstock.</a></span></figcaption></figure><p><strong>How can we see what we are imagining but still see what’s in front of us? – Malala Yousafzai class, Globe Primary School, London, UK.</strong></p>
<p>This question gets right at the heart of a big issue for brain scientists. Say you’re daydreaming in class – you can have your eyes open and be aware of the colours and shapes in the classroom and the movement of your teacher and classmates, while at the same time “seeing” whatever you’re thinking of or imagining. </p>
<p>These two kinds of seeing are quite different, but they both happen in the same part at the back of our brain – the <a href="https://kids.kiddle.co/Visual_cortex">visual cortex</a>. Messages coming from different places can cause the visual cortex to become active, and whenever that happens, you “see” things. </p>
<p>To understand how this happens, imagine that you are a brain. You’re locked up inside a skull – a dark, silent vault. You’re in charge of a body, and you somehow need to know what’s going on in the world around you in order to guide this body successfully. </p>
<hr>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a> is a series by <a href="https://theconversation.com/uk">The Conversation</a>, which gives children the chance to have their questions about the world answered by experts. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskids@theconversation.com">curiouskids@theconversation.com</a>. We won’t be able to answer every question, but we’ll do our very best.</em></p>
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<p>One place the messages can come from is your eyes: light bounces off the objects around you and enters your eyes (if they’re open). The light is then focused onto <a href="http://thebrain.mcgill.ca/flash/d/d_02/d_02_cl/d_02_cl_vis/d_02_cl_vis.html">the retina</a> – a thin layer of light sensitive cells on the back of your eyeball. </p>
<p>The cells in the retina then send messages through the optic nerve, back towards the visual cortex. There, <a href="https://www.sciencedaily.com/releases/2019/09/190909123715.htm">different parts of the visual cortex</a> get to work decoding colours, edges and outlines and movements and faces. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/296866/original/file-20191014-135483-1utlkoo.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/296866/original/file-20191014-135483-1utlkoo.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/296866/original/file-20191014-135483-1utlkoo.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/296866/original/file-20191014-135483-1utlkoo.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/296866/original/file-20191014-135483-1utlkoo.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/296866/original/file-20191014-135483-1utlkoo.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/296866/original/file-20191014-135483-1utlkoo.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/296866/original/file-20191014-135483-1utlkoo.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">How the brain sees.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/visual-projection-pathway-78253603">Alila Medical Media/Shutterstock.</a></span>
</figcaption>
</figure>
<p>The brain then puts all those visual messages back together again, allowing you to see what’s around you. </p>
<h2>Imagining things</h2>
<p>Remember, as far as the brain’s concerned, it doesn’t really matter where the messages are coming from – when the visual cortex is active, you are seeing. </p>
<p>So the messages could also be coming from other parts of your brain – and this is what happens when you see the things you imagine, remember or dream. </p>
<p>For example, sometimes hearing a song can make you remember where you were the last time you heard it. The sound can cause a cascade of activity in the brain: messages go from the parts of the brain that hear, to the parts that remember and eventually to the parts that see – and that’s how you experience a memory. </p>
<h2>Patterns and predictions</h2>
<p>That explains how your brain manages two different ways of seeing. But it takes a <a href="https://hypertextbook.com/facts/2001/JacquelineLing.shtml">lot of energy</a> for your brain to see what’s going on around you, based on the messages it gets from your eyes. So there’s another trick the brain uses for seeing, to help save itself some effort: it tries to predict what’s about to happen, based on your past experiences.</p>
<p>Even before babies are born, they’re already <a href="https://www.britannica.com/topic/infant-perception#ref321346">learning about the patterns</a> that exist in the world. As babies get older, they learn from these patterns to predict what’s going to happen next. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/296939/original/file-20191014-135501-2wszhj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/296939/original/file-20191014-135501-2wszhj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/296939/original/file-20191014-135501-2wszhj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/296939/original/file-20191014-135501-2wszhj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/296939/original/file-20191014-135501-2wszhj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/296939/original/file-20191014-135501-2wszhj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/296939/original/file-20191014-135501-2wszhj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/296939/original/file-20191014-135501-2wszhj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Learning every day.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/portrait-mom-cute-little-newborn-girl-1530181796?src=UlilVJ96S67OcEmeu7GP1A-1-29">PV Productions/Shutterstock.</a></span>
</figcaption>
</figure>
<p>For example, the first time a baby sees her dad goes around a corner, she might think he’s disappeared, and get upset. Then, when dad comes back, the baby might be surprised and happy. </p>
<p>But after this happens a few times, the baby starts to expect that her dad will come back from around the corner, and won’t be surprised anymore. </p>
<h2>Balancing act</h2>
<p>So, your brain is actually making up what you see all the time, based on messages from different places, as well as your expectations. </p>
<p>The brain keeps a delicate balance between these messages and expectations, to help guide you through the world, while also saving energy. </p>
<p>So if the teacher calls your name while you’re daydreaming in class, your brain quickly switches from imagining things, to paying close attention to the messages coming from your senses about what’s going on in the classroom. </p>
<hr>
<p><em>Children can have their own questions answered by experts – just send them in to <a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a>, along with the child’s first name, age and town or city. You can:</em></p>
<ul>
<li><em>email <a href="mailto:curiouskids@theconversation.com">curiouskids@theconversation.com</a></em></li>
<li><em>tweet us <a href="https://twitter.com/ConversationUK">@ConversationUK</a> with #curiouskids</em></li>
<li><em>DM us on Instagram <a href="https://www.instagram.com/theconversationdotcom/">@theconversationdotcom</a></em></li>
</ul>
<p><em>Here are some more <a href="https://theconversation.com/topics/curious-kids-36782?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=CuriousKidsUK">Curious Kids</a> articles, written by academic experts:</em></p>
<ul>
<li><p><em><a href="https://theconversation.com/curious-kids-why-is-the-sea-salty-124743?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=CuriousKidsUK">Why is the sea salty? – Torben, aged nine, Sussex, UK.</a></em></p></li>
<li><p><em><a href="https://theconversation.com/curious-kids-why-do-i-have-boogies-and-why-does-my-nose-keep-replicating-them-122660?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=CuriousKidsUK">Why do I have boogies and why does my nose keep replicating them? – Duncan, aged seven, Sydney, Australia.</a></em></p></li>
<li><p><em><a href="https://theconversation.com/curious-kids-could-humans-live-on-kepler-452-b-123786?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=CuriousKidsUK">Can we live on Kepler 452-b? – Year Five, Globe Primary School, London, UK.</a></em></p></li>
</ul><img src="https://counter.theconversation.com/content/124944/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Niia Nikolova receives funding from The Leverhulme Trust.</span></em></p>Your brain balances messages coming from lots of different places to help you see, imagine, remember and dream.Niia Nikolova, Research Associate, University of Strathclyde Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1090392019-01-15T12:21:18Z2019-01-15T12:21:18ZHow our unconscious visual biases change the way we perceive objects<figure><img src="https://images.theconversation.com/files/253854/original/file-20190115-152977-e05sgo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/oop-something-went-wrong-close-picture-1255191481?src=Dq1JkImjXoW6GLOaL-eXjw-1-44">Roman Samborskyi/Shutterstock</a></span></figcaption></figure><p>As the old saying goes, beauty is in the eye of the beholder. But while we can appreciate that others might hold different opinions of objects we see, not many people know that factors beyond our control can influence how we perceive the basic attributes of these objects. We might argue that something is beautiful or ugly, for example, but we would be surprised to learn that the same object is perceived as a sphere by one person but as a cube by another. </p>
<p>The process of visual perception is a <a href="https://www.sciencedirect.com/science/article/pii/S0042698901001730">best guess</a> scenario. When we look at something, the brain uses visual cues –sensory signals that convey information – to help work out what that thing is. This means that our perception of the world is not a simple reflection of sensory information, it is an <a href="https://www.sciencedirect.com/science/article/pii/S0042698901001730">interpretation</a> of it. </p>
<p>Along with colour and motion, the perception of depth is very important to help us visually perceive things. Depth helps us to understand the shape of objects and their location relative to ourselves. We need to understand it to move around our environment and interact with objects. Imagine trying to pick something up if you don’t know what shape it is, or crossing the road if you can’t accurately perceive the distance of the cars. </p>
<p>To perceive depth, humans and animals rely on a number of brain processes and visual cues. One of these cues is shading information: we can perceive depth by simply interpreting the patterns of light and dark on the surface of objects, without needing to refer to any other information.</p>
<p>In order to perceive depth from shading patterns, we must either know or assume the position of the light source that illuminates the object. By default, if the light source is not apparent, we assume that the light comes from above the object. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/253625/original/file-20190114-43535-1en6bnm.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/253625/original/file-20190114-43535-1en6bnm.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=321&fit=crop&dpr=1 600w, https://images.theconversation.com/files/253625/original/file-20190114-43535-1en6bnm.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=321&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/253625/original/file-20190114-43535-1en6bnm.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=321&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/253625/original/file-20190114-43535-1en6bnm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=404&fit=crop&dpr=1 754w, https://images.theconversation.com/files/253625/original/file-20190114-43535-1en6bnm.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=404&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/253625/original/file-20190114-43535-1en6bnm.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=404&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The circle on the left is usually perceived as convex, while the circle on the right is usually perceived to be concave.</span>
</figcaption>
</figure>
<p>Look at the image to the right. The sphere on the left will most likely appear convex (protruding outwards). This is because it is lighter at the top, which reflects the patterns of light and dark that would be produced on a convex object if there was an overhead light source. The sphere on the right usually looks concave (recessed inwards) because it’s darker at the top. Again, if there was an overhead light source, a concave object would be darker at the top because the upward-facing portions of the object catch the light, and the downward-facing portions are obscured.</p>
<p>The light-from-above assumption isn’t very surprising, since we evolved in a world with an overhead light source – the sun. A less intuitive finding that scientists have made, however, is that light is assumed to originate from the <a href="https://www.nature.com/articles/nn0798_183">upper left-hand side of space</a>. We know this because, in the lab, people are generally faster to detect convex spheres from a group of concave spheres if the convex sphere is lit from the above-left, and they more readily <a href="https://jov.arvojournals.org/article.aspx?articleid=2193838">categorise these left-lit objects as convex</a>. </p>
<p>Experiments that measure electrical activity in the brain have also found that <a href="https://journals.lww.com/neuroreport/Citation/2003/05230/Neural_correlates_of_shape_from_shading.13.aspx">left-lit objects are more rapidly recognised</a> than those lit from other orientations. This is demonstrated in the image below. Both the upper and lower rows of circles contain one that is different from the others – <a href="https://www.biac.duke.edu/library/papers/2004_Neuropsychologia_Huettel.pdf">an oddball</a>. The oddball in the top row is lit from the above-left and it should “pop out” from the others, which have an exactly opposite shading pattern. The circles in the lower line also have an opposite shading pattern, but the oddball is much harder to detect because its shading pattern does not conform to our above-left expectations. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/253760/original/file-20190114-43535-133b7tv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/253760/original/file-20190114-43535-133b7tv.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=285&fit=crop&dpr=1 600w, https://images.theconversation.com/files/253760/original/file-20190114-43535-133b7tv.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=285&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/253760/original/file-20190114-43535-133b7tv.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=285&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/253760/original/file-20190114-43535-133b7tv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=358&fit=crop&dpr=1 754w, https://images.theconversation.com/files/253760/original/file-20190114-43535-133b7tv.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=358&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/253760/original/file-20190114-43535-133b7tv.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=358&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The oddball sphere should pop out from among the others in the top line, but is much more difficult to see in the bottom line (it is the final circle in the sequence).</span>
</figcaption>
</figure>
<p>However, like the overhead light source assumption, the leftward light source bias exists outside conscious awareness. And not everyone experiences it. For example, people who read from right-to-left (such as Arabic or Hebrew readers) sometimes show rightward biases or <a href="https://jov.arvojournals.org/article.aspx?articleid=2193838">smaller left biases</a> than people who read left-to-right. Interestingly, people who have recently suffered a stroke in the right-hemisphere parietal lobe <a href="https://www.sciencedirect.com/science/article/abs/pii/S0278262609001821">typically demonstrate a rightward light source bias</a> too. This could indicate that the right parietal lobe – which is responsible for <a href="https://www.neuroskills.com/brain-injury/parietal-lobes.php">perceiving the physical environment and integrating</a> information from the senses, such as sight and hearing – is ordinarily responsible for orienting visual attention to the left side of space, because disrupting the normal function of that region shifts attention rightward. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/253624/original/file-20190114-43541-10a5i3y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/253624/original/file-20190114-43541-10a5i3y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=540&fit=crop&dpr=1 600w, https://images.theconversation.com/files/253624/original/file-20190114-43541-10a5i3y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=540&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/253624/original/file-20190114-43541-10a5i3y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=540&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/253624/original/file-20190114-43541-10a5i3y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=679&fit=crop&dpr=1 754w, https://images.theconversation.com/files/253624/original/file-20190114-43541-10a5i3y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=679&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/253624/original/file-20190114-43541-10a5i3y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=679&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The honeycomb stimulus: some people perceive the central hexagon as convex, others as concave.</span>
</figcaption>
</figure>
<p>The fact that a person’s culture or brain changes can result in subjective differences in perception means that some people will perceive concavity in certain images, whereas others will perceive convexity. The honeycomb image to the right is one example that we use experimentally to find out how someone perceives depth from shading. Some people will perceive the central hexagon as convex, while others (usually those with a left bias) as concave.</p>
<p>We all assume everyone perceives the world as we do, even if their impressions might be different from ours. It is difficult to imagine that some people might perceive three-dimensional depth differently from ourselves. But if our perception of something as basic as whether an object is convex or concave is not reliably the same across people and populations, how can we begin to judge the subjective experience? Biases in visual perception might explain some differences in aesthetic judgements, but if we can explain why different people have an opposite perception of the same thing, it could, ultimately, further our understanding of human cognition on a wider scale.</p><img src="https://counter.theconversation.com/content/109039/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Beverley Pickard-Jones received funding from the James Pantyfedwen Foundation in 2017.</span></em></p>We rely on depth to perceive objects, but not all of us see depth in the same way.Beverley Pickard-Jones, PhD Researcher, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1030642018-09-18T06:11:42Z2018-09-18T06:11:42ZCurious Kids: why do things look smaller when further away and bigger when closer to me?<figure><img src="https://images.theconversation.com/files/236669/original/file-20180917-158228-1850gl0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/little-girl-on-green-grass-meadow-13260748?src=u1FXZ8hFmzrOJPfc_-RFqA-1-5">Shutterstock.</a></span></figcaption></figure><p><em>This is an article from <a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a>, a series for children of all ages. The Conversation is asking young people to send in questions they’d like an expert to answer. All questions are welcome: find out how to enter at the bottom.</em> </p>
<hr>
<blockquote>
<p><strong>Why do things look smaller when further away and bigger when closer to me? – Elena, age ten, Haywards Heath, UK</strong></p>
</blockquote>
<p>The easiest way to understand this is by thinking about something called your field of view. This is how much you can see, without turning your head. When things are closer to you, they take up more of your field of view, so they seem bigger. When they’re further away, they take up less of your field of view, and so seem smaller. </p>
<p>One way to measure our field of view is to use an angle. An angle is a measure of how much something turns, and it’s measured in degrees. Zero degrees means there is no turn at all, while 360 degrees means a full turn. </p>
<p>So if you spin yourself all the way around, you have turned 360 degrees. If you spin yourself half way around, so that you’re facing the opposite direction, you’ve turned 180 degrees.</p>
<p>Vertically (that means up and down) our field of view is about 150 degrees. How big things appear to us has to do with how much of our field of view they take up. </p>
<p>If you look at a building from a long way away, you can easily see the whole building from top to bottom. So the angle between the line from your eye to the top of the building, and the line from your eye to the bottom of the building, is quite small. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/236658/original/file-20180917-158213-15ka9ii.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/236658/original/file-20180917-158213-15ka9ii.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/236658/original/file-20180917-158213-15ka9ii.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/236658/original/file-20180917-158213-15ka9ii.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/236658/original/file-20180917-158213-15ka9ii.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/236658/original/file-20180917-158213-15ka9ii.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/236658/original/file-20180917-158213-15ka9ii.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The black arrows show your field of vision – the building takes up a small part.</span>
<span class="attribution"><span class="source">Shutterstock/The Conversation UK.</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The further away the object is, the smaller this angle will be. So, the subject appears small, because it takes up less of your field of view. </p>
<p>But as you get closer to the building, it will take up more and more of your field of view, as the angle between the line from your eye to the top of the building, and the line from your eye to the bottom of the building, grows larger. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/236661/original/file-20180917-158234-1u842ye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/236661/original/file-20180917-158234-1u842ye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/236661/original/file-20180917-158234-1u842ye.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/236661/original/file-20180917-158234-1u842ye.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/236661/original/file-20180917-158234-1u842ye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/236661/original/file-20180917-158234-1u842ye.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/236661/original/file-20180917-158234-1u842ye.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The building is closer, and takes up more of your field of view.</span>
<span class="attribution"><span class="source">Shutterstock/The Conversation UK.</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>When you get right up close to the building, you may not even be able to see the top without tipping your head backwards. The angle between the line from you to the bottom of the building, and the line from you to the top is bigger than 150 degrees. The building will take up your whole field of view – and then some! </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/236664/original/file-20180917-158219-1i3r43p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/236664/original/file-20180917-158219-1i3r43p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/236664/original/file-20180917-158219-1i3r43p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/236664/original/file-20180917-158219-1i3r43p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/236664/original/file-20180917-158219-1i3r43p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/236664/original/file-20180917-158219-1i3r43p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/236664/original/file-20180917-158219-1i3r43p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">You can’t even see the top anymore, without tilting your head.</span>
<span class="attribution"><span class="source">Shutterstock/The Conversation UK.</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Scientists know that things are always better with experiments, so here’s one for you to try. You’ll need a smart phone with a camera, a big empty space (like a football field) and two friends or grown ups to help you. </p>
<p>One person stands far away, at the other end of the field. Another person stands much closer to the photographer, and holds out their hand. Now, the photographer might have to move around a little bit and give everyone directions, but as soon as everything is in line – click! </p>
<p>You should have a picture that looks something like this. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/236665/original/file-20180917-158216-1y9w01m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/236665/original/file-20180917-158216-1y9w01m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/236665/original/file-20180917-158216-1y9w01m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/236665/original/file-20180917-158216-1y9w01m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/236665/original/file-20180917-158216-1y9w01m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/236665/original/file-20180917-158216-1y9w01m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/236665/original/file-20180917-158216-1y9w01m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Say cheese!</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/dark-haired-female-stands-on-bolivian-1064148797?src=gPdxM8SKfMFcYrv10uoU5A-1-40">Shutterstock.</a></span>
</figcaption>
</figure>
<p>Of course, one person isn’t really that much smaller than the other – you’re actually just playing a trick, using everything you’ve just learned. </p>
<p>The camera is very much like your eye, so you know that the person who is closer to the camera will take up more of its “field of view”, appearing bigger, while the person who is further away will take up less of its “field of view”, appearing smaller. </p>
<hr>
<p><em>Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. You can:</em></p>
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<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><em>Please tell us your name, age and which town or city you live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won’t be able to answer every question, but we will do our best.</em></p>
<hr>
<p><em>More <a href="https://theconversation.com/topics/curious-kids-36782?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=CuriousKidsUK">Curious Kids</a> articles, written by academic experts:</em></p>
<ul>
<li><p><em><a href="https://theconversation.com/curious-kids-how-do-you-know-that-we-arent-in-virtual-reality-right-now-98832?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=CuriousKidsUK">How do you know that we aren’t in virtual reality right now? – Erin, 13, Strathfield, Australia</a></em></p></li>
<li><p><em><a href="https://theconversation.com/curious-kids-if-the-universe-is-like-a-giant-brain-then-wheres-its-body-102952?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=CuriousKidsUK">If the universe is like a giant brain, then where’s its body? – Aine, age 12, Edinburgh, UK</a></em></p></li>
<li><p><em><a href="https://theconversation.com/curious-kids-how-does-our-heart-beat-102609?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=CuriousKidsUK">How does our heart beat? – Aarav, age nine, Mumbai, India</a></em></p></li>
</ul><img src="https://counter.theconversation.com/content/103064/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Franklin does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Your field of view is how much you can see without turning your head. When things are closer to us, they take up more of our field of view, which makes them look bigger.David Franklin, Associate Head of Education, University of PortsmouthLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1022822018-09-07T14:00:25Z2018-09-07T14:00:25ZDo blind people have better hearing?<figure><img src="https://images.theconversation.com/files/234863/original/file-20180904-45151-1vync4t.jpg?ixlib=rb-1.1.0&rect=51%2C0%2C5760%2C3837&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/1007019028?src=3R37ZLjnzeuDE8nl6Spl3A-1-28&size=huge_jpg">Africa Studio/Shutterstock</a></span></figcaption></figure><p>The sensation of sound occurs when the vibrations from sounds enter our ear and cause little hairlike structures – called hair cells – within our inner ear to move back and forth. The hair cells transform this movement into an electrical signal that the brain can use. </p>
<p>How well a person can hear largely depends on how intact these hair cells are. Once lost, they don’t grow back – and this is no different for blind people. So blind people can’t physically hear better than others.</p>
<p>Yet blind people often outperform sighted people in hearing tasks such as <a href="https://www.sciencedirect.com/science/article/pii/S0378595515300174">locating the source of sounds</a>. The reason for this emerges when we look beyond the sensory organs, at what is happening with the brain, and how the sensory information is processed by it. </p>
<p>Perception occurs when the brain interprets signals that our sensory organs provide, and different parts of the brain respond to the information arriving from different sensory organs. There are areas that process visual information (the visual cortex) and areas that process sound information (the auditory cortex). But when a sense like vision is lost, the brain does something remarkable: it <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3898172/">reorganises the functions of these brain areas</a>. </p>
<p>In blind people, the visual cortex gets a bit “bored” without visual input and starts to “rewire” itself, becoming more responsive to information from the other remaining senses. So blind people may have lost their vision, but this leaves a larger brain capacity for processing the information from other senses. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/234867/original/file-20180904-45135-9p33j5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/234867/original/file-20180904-45135-9p33j5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=494&fit=crop&dpr=1 600w, https://images.theconversation.com/files/234867/original/file-20180904-45135-9p33j5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=494&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/234867/original/file-20180904-45135-9p33j5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=494&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/234867/original/file-20180904-45135-9p33j5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=621&fit=crop&dpr=1 754w, https://images.theconversation.com/files/234867/original/file-20180904-45135-9p33j5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=621&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/234867/original/file-20180904-45135-9p33j5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=621&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The visual cortex can rewire itself to respond to sounds or touch.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/134423357?size=huge_jpg">Cliparea/Shutterstock</a></span>
</figcaption>
</figure>
<p>The extent of reorganisation in the brain depends on when someone loses their sight. The <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3898172/">brain can reorganise itself at any point in life</a>, including adulthood, but during childhood the brain is more able to adapt to change. This is because during childhood the brain is still developing and the new organisation of the brain does not have to compete with an existing one. As a result, people who have been blind from a very early age show a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3898172/">much greater level of reorganisation in the brain</a>. </p>
<p>People who become blind early in life tend to outperform sighted people, as well as those who became blind later in life, in <a href="https://www.nature.com/articles/430309a">hearing</a> and <a href="https://www.sciencedirect.com/science/article/pii/S0960982203009849">touch</a> perceptual tasks.</p>
<h2>Echolocation</h2>
<p>The reorganisation in the brain also means that blind people are sometimes able to learn how to use their remaining senses in interesting ways. For example, some blind people learn to sense the location and size of objects around them using <a href="https://community.dur.ac.uk/lore.thaler/thaler_goodale_echo_review2016.pdf">echolocation</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/2IKT2akh0Ng?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>By producing clicks with their mouths and listening for the echoes, blind people can locate objects in their surroundings. This ability is tightly linked with the <a href="https://community.dur.ac.uk/lore.thaler/thaler_goodale_echo_review2016.pdf">brain activity in the visual cortex</a>. In fact, the visual cortex in blind echolocators responds to sound information in almost the same way as it does to visual information in the sighted. In other words, in blind echolocators, hearing has replaced vision in the brain to a very large extent.</p>
<p>But not every blind person is automatically an expert echolocator. Whether a blind person is able to develop a skill like echolocation depends on the time spent learning this task – <a href="https://www.sciencedirect.com/science/article/pii/S0378595514000185">even sighted people can learn this skill with enough training</a>, but blind people will probably benefit from their reorganised brain being more tuned towards the remaining senses. </p>
<p>Blind people will also rely more on their remaining senses to do everyday tasks, which means that they train their remaining senses on a daily basis. The reorganised brain together with the greater experience in using their remaining senses are believed to be important factors in blind people having an edge over sighted people in hearing and touch.</p><img src="https://counter.theconversation.com/content/102282/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Loes van Dam is an Associate Editor for the journal Attention, Perception, & Psychophysics </span></em></p>Blind people don’t have superhuman ears but their brains can rewire themselves to give them an edge over those who can see.Loes van Dam, Lecturer in Psychology, University of EssexLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/831502017-09-12T19:39:50Z2017-09-12T19:39:50ZCurious Kids: Why it is that the things close to the train windows zoom by really fast, but things further away seem to go by much slower?<figure><img src="https://images.theconversation.com/files/183689/original/file-20170829-1590-17fsdj4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">When looking out of a train window, things close by seem to move past faster than things that are far away.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/trippinlarry/5442289138/in/photolist-9hV9Xm-dqwcad-49JMqS-4qWKqs-coqLKJ-amJdQt-9NEdXe-e5Euti-9e9Rsh-kmvYe8-h9ZoGP-Xgrbor-fPxNm2-kmweir-X3svEo-81Rq8b-o6zhX1-ij895V-5mSoVV-T98yfg-CeFWKx-81FrFK-jobDGU-8xcLkf-4jpoev-26v3yq-6DvVuR-edLav9-qFZbye-WDgL5G-8RSQ7A-aN32t2-81JA6w-3ajXzm-9zdoE-9MYCMM-qFZztn-EqtMd5-kmyGRh-qD9BEp-hVKHK4-9VxnA-kmwfRX-aN76bB-6kEdMs-avmDkN-6kEFcN-9NEYMC-v1MRp-RqW2Cs">Flickr/Larry W. Lo</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p><em>This is an article from <a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a>, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!</em> </p>
<hr>
<blockquote>
<p><strong>Why it is that the things close to the train windows zoom by really fast, but things further away seem to go by much slower? – Ada, age 7, Katoomba.</strong></p>
</blockquote>
<hr>
<p>Superb question, Ada!</p>
<p>Things close to the train window seem to zoom by very fast because they appear much larger than things that are far away. </p>
<p>Imagine looking out of a window. Suppose you see a big tree, one that is 10 metres wide, far away in the distance. When you push your thumb against the window, you can cover the whole tree, even though the tree is much bigger than your thumb. </p>
<p>Now, imagine you have an ant on the nail of your thumb. As you have your thumb pressed against the window, the ant takes one second to walk from the left to the right of your thumbnail. </p>
<p>Now imagine at the same moment, a cat runs halfway across the 10 metre wide tree in the distance.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/183691/original/file-20170829-1572-1qyxy3n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/183691/original/file-20170829-1572-1qyxy3n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/183691/original/file-20170829-1572-1qyxy3n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/183691/original/file-20170829-1572-1qyxy3n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/183691/original/file-20170829-1572-1qyxy3n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/183691/original/file-20170829-1572-1qyxy3n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/183691/original/file-20170829-1572-1qyxy3n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Things close to the train window seem to zoom by very fast because they appear much larger than things that are far away.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/sean_hickin/12279442396/in/photolist-WpKjDD-SAtxqj-bAJxTd-bL2iy4-eXJSfJ-f8Ypyj-pc2iSi-bBGQBE-jH6mq5-8izcAE-qeECVs-oNhiqV-oNgA1c-nGubzd-aScZi-pnimXB-bzG7ds-p5v9UP-FZKR43-TG9Wdt-oNhgr5-4eLgJx-p3jgzk-kviEzk-ka4dYr-sbyp4e-6nNNyP-T71cze-WyCLMW-aF5Rv8-ioNkj5-bcKkev-Ru2bAa-aikpnr-8SzbM9-U6E1aP-47mmSv-s82N5E-84Egff-6TifSk-qr4HZ5-kTvy7x-qCDHaj-iMhzV3-iH2wVE-bsXHAJ-7KXfV3-FY3dEy-3WmTae-ouwwtZ">Flickr/Sean Hickin</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Even though the cat is faster than the ant (it has run five metres in one second), in your eyes, the cat seems to have only travelled half a thumb width in one second, while the ant has travelled one whole thumb width in one second. The ant <em>seems</em> to zoom by faster than the cat, even though in reality, it is much slower.</p>
<p>If you look at an aeroplane high in the sky, what you discover is even more fascinating. Imagine covering the image of the plane with your thumb as it zooms across the sky. The ant took one second to cross your thumb. The cat needed two seconds. The plane might need five seconds! So, the plane seems to be slower than both the ant and the cat, but we know that planes are in fact much faster. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/183690/original/file-20170829-12314-1sb9ctf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/183690/original/file-20170829-12314-1sb9ctf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/183690/original/file-20170829-12314-1sb9ctf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/183690/original/file-20170829-12314-1sb9ctf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/183690/original/file-20170829-12314-1sb9ctf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/183690/original/file-20170829-12314-1sb9ctf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/183690/original/file-20170829-12314-1sb9ctf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Distant objects take longer to cross our line of vision than ones close by.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/sushicam/6985203242/in/photolist-bDfZyE-VTXW6M-3Peoq-Vgucto-aySXVG-5xuJuw-sz8Xt-V3ocU1-bq4GTt-81JzpW-apKYx5-e7DLGq-UhBicD-Curwec-5LDsTX-4bNXkV-VVigdw-9eh8Vi-qcm2tA-dNuUWC-SPhwaZ-aZBeNv-8fwvFX-5Adove-6FfJbo-fPxGqz-ks3yW4-DWmo9-daTqKi-aocv6i-agmxPg-mk1Ykq-9cW7LA-e3ne6z-e7kKVL-9Apnsq-9Amojz-2bY7z-4jSuFD-byKJro-cakUpY-a94XEj-7BTnCP-ioeeF7-bmC5MM-7sgwBh-g2LPA-THFfTv-mTsSxQ-iBxeX">Flickr/Jeff Laitila</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Things appear to move slower when they are far away because they seem smaller, and take longer to cross our line of vision. Likewise, they appear to move faster when they are close by, because they seem bigger.</p>
<p>PS: You have the same first name as a very famous scientist! Ada Lovelace was one of the first people to think of how to design a computer. She was also one of the first to write computer programmes. This was super clever for someone born over 200 years ago, and her work has helped shape the world we live in today. </p>
<hr>
<p><em>Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. You can:</em></p>
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<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><em>Please tell us your name, age and which city you live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won’t be able to answer every question but we will do our best.</em></p><img src="https://counter.theconversation.com/content/83150/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Paganin receives funding from the Australian Research Council.</span></em></p>Ada, 7, wants to know why things close to the train windows zoom by really fast, while things further away seem to go by much slower.David Paganin, Adjunct Professor (Research) in Physics, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/747902017-04-03T15:00:39Z2017-04-03T15:00:39ZCountries like Kenya are woefully behind the curve in managing glaucoma<figure><img src="https://images.theconversation.com/files/162687/original/image-20170327-3303-1gvmyei.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Accurate diagnosis of glaucoma requires trained specialists and advanced equipment.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p><em>Glaucoma is the <a href="https://www.ncbi.nlm.nih.gov/pubmed/12745004">leading cause</a> of irreversible blindness in the world. The disease is known as ‘the sneak <a href="http://www.webmd.com/eye-health/glaucoma-eyes#2">thief of vision</a>’ because there are no early warning signs or painful symptoms leading to its diagnosis. The Conversation Africa’s Health and Medicine Editor Joy Wanja Muraya asked Professor Dan Kiage to explain the challenges African countries face in managing the disease.</em></p>
<p><strong>What are the top concerns about treating and managing glaucoma in Africa?</strong></p>
<p>Glaucoma is a slow and silent progressive disease that damages the <a href="https://nei.nih.gov/health/glaucoma/glaucoma_facts">optic nerve</a> of the eye.
If not treated, it can lead to gradual loss of sight where the individual sees blind spots and may eventually go blind. About <a href="http://www.who.int/blindness/causes/priority/en/index6.html">4.5 million</a> people are blind due to glaucoma, a number that’s expected to more than <a href="https://nei.nih.gov/eyedata/glaucoma">double</a> by 2020.</p>
<p>Glaucoma disproportionately affects <a href="http://eyewiki.aao.org/Glaucoma_in_the_Developing_World">Africans</a>. Their higher risk remains unclear though some studies have related it to <a href="http://www.brightfocus.org/glaucoma/article/glaucoma-african-american-and-hispanic-communities">genetic differences</a> in the anatomic structure of the optic nerve. </p>
<p>The diagnosis of glaucoma in Africa is really low. One study shows that in rural villages in East Africa only <a href="https://www.ncbi.nlm.nih.gov/pubmed/10634599">2% to 3%</a> of the patients with glaucoma had been diagnosed. This is partly due to the fact that sub-Saharan Africa has the <a href="http://glaucomatoday.com/2013/08/meeting-the-challenge-of-glaucoma-in-africa/">lowest ratios </a> of health workers to population anywhere in the world. And patients seek medical treatment quite late.</p>
<p>Accurate diagnosis of early glaucoma requires well trained ophthalmologists and advanced equipment. But in sub-Saharan Africa the majority of primary and secondary health care centres are run by <a href="http://www.worldglaucoma.org/AfricaSummit/Download/Budenz_Global_Perspectives_African_Glaucoma.pdf">poorly equipped</a> lower cadres of eye care workers who lack the skills and capacity to accurately diagnose advanced symptomatic stages of glaucoma. </p>
<p>Glaucoma medicines are also not widely available, and they’re <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3381080/">expensive</a>. </p>
<p><strong>Who is most at risk? Are Africans receiving appropriate glaucoma treatment?</strong></p>
<p>Anybody is at <a href="https://patient.info/doctor/glaucoma-and-ocular-hypertension">risk</a>, though some people face a <a href="http://www.glaucoma.org/glaucoma/are-you-at-risk-for-glaucoma.php">higher </a> risk of getting the disease. </p>
<p>These include people </p>
<ul>
<li><p>with a history of glaucoma in the family</p></li>
<li><p>aged over 40 years old</p></li>
<li><p>black race </p></li>
<li><p>with symptoms such as short slightness, known as myopia </p></li>
<li><p>with other predisposing symptoms like migraines, low blood pressure at night known as nocturnal hypotension, diabetes mellitus and thyroid disease. </p></li>
</ul>
<p>For people with this risk factors, routine eye examinations is mandatory.</p>
<p>Glaucoma can be diagnosed early through a regular eye check up by an eye specialist. Once diagnosed, a person has to commit to lifelong follow up appointments.</p>
<p><strong>What is Kenya doing about the gaps?</strong></p>
<p>The lack of resources to deal with glaucoma in Africa is shocking. For example, Kenya has <a href="http://www.tandfonline.com/doi/full/10.1080/17469899.2017.1295848?scroll=top&needAccess=true">two</a> qualified glaucoma specialists. This is clearly <a href="http://medicalkenya.co.ke/2011/07/kenyan-doctor-heading-home-after-training-to-treat-glaucoma/">not enough</a> but it’s a step ahead of most countries in Africa which have none.</p>
<p>Kenya has taken steps to plug the gap. Every county referral hospital now has an eye health specialist, or ophthalmologist, with basic diagnostic and treatment tools for glaucoma.</p>
<p>And since 2006 Kenya has collaborated with other countries in the region and partnered with advanced centres in Canada in a program called <a href="http://www.tandfonline.com/doi/full/10.1080/17469899.2017.1295848?scroll=top&needAccess=true">STOP Glaucoma in Sub Saharan Africa</a>.</p>
<p>The <a href="http://www.tandfonline.com/doi/full/10.1080/17469899.2017.1295848?scroll=top&needAccess=true">four main pillars</a> of the program include building capacity, enhancing awareness and improving glaucoma detection and management. </p>
<p>The aim of the initiative is also to <a href="http://www.tandfonline.com/doi/full/10.1080/17469899.2017.1295848?scroll=top&needAccess=true">train </a> the first generation of highly qualified glaucoma sub-specialist leaders and develop standards of care and guidelines for management of glaucoma in the region.</p>
<p>In addition, a glaucoma community team <a href="http://www.coecsa.org/">has been developed</a> to bring eye specialists together. It established <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3588128/">guidelines</a> for glaucoma treatment and management of the disease in Africa.</p>
<p>The ultimate aim is to reduce the burden of blindness from glaucoma in sub Saharan Africa.</p>
<p><strong>What is the way forward for dealing with glaucoma in Africa?</strong></p>
<p>The main approaches for tackling glaucoma in Africa include; </p>
<ul>
<li><p>Increased <a href="http://www.nation.co.ke/Features/Living/Congenital+glaucoma+Look+out+for+these+symptoms+++/-/1218/1370034/-/item/0/-/af1kh8/-/index.html">public awareness</a>.</p>
<ul>
<li>Sustained training of glaucoma specialists for all referral and training centres in Africa.</li>
<li>Equipping health facilities with appropriate diagnostic and treatment apparatus.</li>
<li>Stocking and dispensing affordable drugs for managing glaucoma.</li>
</ul></li>
</ul>
<p>There are also new technologies that should be made more readily available to health personnel. These include tele medicine – remote diagnosis and treatment using telecommunications technology – and laser treatment, known as <a href="http://sanantonioeyeinstitute.com/selective-laser-trabeculoplasty-slt/">trabeculoplasty,</a> which uses focused light rays to reduce pressure in the eye.</p>
<p>It’s the responsibility of the governments in Africa to facilitate socio-economic growth to ensure literacy is improved. This way, people will have Universal healthcare so that they can access the appropriate facilities.</p><img src="https://counter.theconversation.com/content/74790/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel Oira Kiage does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Glaucoma is a slow and silent progressive disease and the second leading cause of blindness, that requires early diagnosis.Daniel Oira Kiage, Professor of Glaucoma , College of Ophthalmology of Eastern Central and Southern AfricaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/741012017-03-13T12:12:31Z2017-03-13T12:12:31ZHow do animals see in the dark?<figure><img src="https://images.theconversation.com/files/160493/original/image-20170313-19270-be2f9q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">_Megalopta genalis_.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/usgsbiml/15121397069/">United States Geological Survey</a></span></figcaption></figure><p>On a moonless night, light levels can be more than 100m times <a href="http://bit.ly/2mZLkEL">dimmer than in bright daylight</a>. Yet while we are nearly blind and quite helpless in the dark, cats are out stalking prey, and moths are flying agilely between flowers on our balconies.</p>
<p>While we sleep, millions of other animals rely on their visual systems to survive. The same is true of animals who inhabit the eternal darkness of the deep sea. In fact, the overwhelming majority of the world’s animals are primarily active in dim light. How is their formidable visual performance possible, especially in insects, with tiny eyes and brains less than the size of a grain of rice? What optical and neural strategies have they evolved to allow them to see so well in dim light?</p>
<p>To answer these questions, we turned our attentions to nocturnal insects. Despite their diminutive visual systems, it turns out that nocturnal insects see amazingly well in dim light. In recent years we have discovered that nocturnal insects can avoid and fixate on obstacles <a href="http://science.sciencemag.org/content/348/6240/1245">during flight</a>, <a href="http://www.nature.com/nature/journal/v419/n6910/full/nature01065.html">distinguish colours</a>, <a href="http://bit.ly/2mi1XqU">detect faint movements</a>, learn visual landmarks and <a href="http://bit.ly/2miaSIF">use them for homing</a>. They can even orient themselves using the faint celestial polarisation pattern <a href="http://www.nature.com/nature/journal/v424/n6944/full/424033a.html">produced by the moon</a>, and navigate using the constellations of <a href="http://bit.ly/2nvmNUu">stars in the sky</a>.</p>
<p>In many cases, this visual performance seems almost to defy what’s physically possible. For example, the nocturnal Central American sweat bee, <em>Megalopta genalis</em>, absorbs just five photons (light particles) into its tiny eyes when light levels are at their lowest – a <a href="http://bit.ly/2miaSIF">vanishingly small visual signal</a>. And yet, in the dead of night, it can navigate the dense and tangled rainforest on a foraging trip and make it safely back to its nest – an inconspicuous hollowed-out stick suspended within the forest understorey.</p>
<p>To find out how this kind of performance is possible, we recently began to study nocturnal hawkmoths. These beautiful insects –- the hummingbirds of the invertebrate world –- are sleek, fast-flying moths that are constantly on the lookout for nectar-laden flowers. Once a flower is found, the moth hovers in front of it, sucking the nectar out using its proboscis, a mouth-like tube.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Deilephila elpenor</em>.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>The nocturnal European Elephant hawkmoth, <em>Deilephila elpenor</em>, is a gorgeous creature cloaked in feathery pink and green scales and does all its nectar gathering in the dead of night. A number of years ago we discovered that this moth can distinguish colours at night, the first nocturnal animal <a href="http://www.nature.com/nature/journal/v419/n6910/full/nature01065.html">known to do so</a>.</p>
<p>But this moth recently revealed another of its secrets: the neural tricks it uses to see well in extremely dim light. These tricks are certainly used by other nocturnal insects like <em>Megalopta</em>. By studying the physiology of neural circuits in the visual centres of the brain, we discovered that <em>Deilephila</em> can see reliably in dim light by effectively adding together the photons it has collected from different points <a href="http://bit.ly/2mi1XqU">in space and time</a>.</p>
<p>For time, this is a little like increasing the shutter time on a camera in dim light. By allowing the shutter to stay open longer, more light reaches the image sensor and a brighter image is produced. The downside is that anything moving rapidly – like a passing car – will not be resolved and so the insect won’t be able to see it.</p>
<h2>Neural summation</h2>
<p>To add together photons in space, the individual pixels of the image sensor can be pooled together to create fewer but larger (and so more light-sensitive) “super pixels”. Again, the downside of this strategy is that even though the image becomes brighter, it also becomes blurrier and finer spatial details disappear. But for a nocturnal animal straining to see in the dark, the ability to see a brighter world that is coarser and slower is likely to be better than seeing nothing at all (which would be the only alternative).</p>
<p>Our physiological work has revealed that this neural summation of photons in time and space is immensely beneficial to nocturnal <em>Deilephila</em>. At all nocturnal light intensities, from dusk to starlight levels, summation substantially boosts <em>Deilephila</em>’s ability to see well in dim light. In fact, thanks to these neural mechanisms, <em>Deilephila</em> can see at light intensities around 100 times dimmer than it could otherwise. The benefits of summation are so great that other nocturnal insects, like <em>Megalopta</em>, very likely rely on it to see well in dim light as well.</p>
<p>The world seen by nocturnal insects may not be as sharp or as well resolved in time as that experienced by their day-active relatives. But summation ensures that it is bright enough to detect and intercept potential mates, to pursue and capture prey, to navigate to and from a nest and to negotiate obstacles during flight. Without this ability it would be as blind as the rest of us.</p><img src="https://counter.theconversation.com/content/74101/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eric Warrant receives funding from the Swedish Research Council (VR), the European Research Council (ERC), the Air Force Office of Scientific Research (ERC), the Wallenberg Foundation and the Royal Physiographic Society. He is a Fellow of the Royal Danish Academy of Sciences and Letters, Fellow and Board Member of the Royal Physiographic Society, Member and President Elect of the International Society of Neuroethology, Chairman of the Organismic Biology Panel of the Swedish Research Council and Vice Chair of the National Committee for Biology at the Royal Swedish Academy of Sciences.</span></em></p>Nocturnal insects have eyes that act like cameras to enhance their light-gathering abilities.Eric Warrant, Professor of Zoology, Lund UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/471752015-09-08T14:56:01Z2015-09-08T14:56:01ZOur peripheral vision is far more sophisticated than we thought<figure><img src="https://images.theconversation.com/files/94024/original/image-20150907-1996-wksjf3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Me, myself and eye</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/s/eye/search.html?page=3&thumb_size=mosaic&inline=245692879">air009</a></span></figcaption></figure><p>From owls to butterflies to monkeys, there are many examples where the visual part of the brain has evolved to devote more resources to tasks that are particularly important for a species. Nocturnal animals like owls have enhanced night vision at the expense of good colour vision, <a href="http://www.sciencedirect.com/science/article/pii/S0960982203000319">for example</a>. This type of trade-off is important because having a bigger brain comes at a cost for animals. A big brain is heavy, for a start, and also requires feeding. The energy consumption of the human brain <a href="http://www.researchgate.net/publication/247931505_Metabolism_of_the_central_nervous_system_in_vivo">exceeds that</a> of any other organ, including the heart. </p>
<p>Most research on vision has concentrated on the small central part of our visual field. This is the part where we see best; the part tested with the letter chart by your optometrist. And it really is very small. Hold your fist directly in front of you at arm’s length – that’s about the area that we are talking about. The vision outside this central area is a good deal less sharp. Evolution has resulted in an elegant solution. Vision is good enough in the periphery only to attract your attention to an object. To explore it with higher resolution, you can then look at it directly if you choose. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/94026/original/image-20150907-1999-1djhqxj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/94026/original/image-20150907-1999-1djhqxj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/94026/original/image-20150907-1999-1djhqxj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=818&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94026/original/image-20150907-1999-1djhqxj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=818&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94026/original/image-20150907-1999-1djhqxj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=818&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94026/original/image-20150907-1999-1djhqxj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1028&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94026/original/image-20150907-1999-1djhqxj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1028&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94026/original/image-20150907-1999-1djhqxj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1028&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The rest is peripheral.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/s/fist/search.html?page=3&thumb_size=mosaic&inline=245290474">Charlie Edwards</a></span>
</figcaption>
</figure>
<p>That’s not the only use we have for peripheral vision, however. Imagine the scene: you are enjoying dinner with a friend and are engaged in a stimulating conversation. Without taking your eyes off your companion, you reach for a glass of wine, pick it up and take a drink. This feels effortless, but the brain needs to form an accurate picture of the shape and size of the glass and where it is located. (Grasping does also rely on touch, but we first judge the object’s size and shape with our eyes and then reach out and adjust our grasp to match what we have perceived.) </p>
<h2>Unequal peripheries</h2>
<p>Because human arms and hands are below our eyes, reaching out often takes place below eye level – as does the manipulation of objects. We and our research colleagues <a href="http://www.ncbi.nlm.nih.gov/pubmed/26067536">wondered whether</a> the visual brain might have adapted to this through evolution, resulting in a visual system that is more finely tuned below than above eye level. </p>
<p>We tested this idea using a task in which we asked six young adults to compare shapes presented on a computer screen to see if they could tell the difference between a perfect circle and a slightly distorted circle (vision studies like these typically use small subject groups because of extensive testing per head). As we expected, they performed best when they looked directly at these shapes. </p>
<p>We then repeated the test for shapes presented above and below eye level, and also to either side. Sure enough, our subjects were much better at judging the shapes when they were presented in their lower visual field. In fact, they were more than 50% better at this compared to when the shapes were either above or to either side.</p>
<p>If this was an evolutionary development, it would make sense that our lower-field vision was better than our other peripheral vision only to the extent that it allowed us to process the shape but not the type of the object. To see whether this was indeed the case, we repeated the experiments with a specific type of object: faces. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/94027/original/image-20150907-2002-9xatfk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/94027/original/image-20150907-2002-9xatfk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/94027/original/image-20150907-2002-9xatfk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=902&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94027/original/image-20150907-2002-9xatfk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=902&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94027/original/image-20150907-2002-9xatfk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=902&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94027/original/image-20150907-2002-9xatfk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1133&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94027/original/image-20150907-2002-9xatfk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1133&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94027/original/image-20150907-2002-9xatfk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1133&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For your middle eye only.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&autocomplete_id=&search_tracking_id=ncV4nUnMxm1noOjCAL1EEQ&searchterm=potato%20head&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=44258767">Ivonne Wierink</a></span>
</figcaption>
</figure>
<p>Faces are considered to be a particularly important class of visual stimuli for humans. Humans are social animals and accurate face perception is central to social functioning. Good face perception allows you instantly to recognise familiar people, distinguish friends from foes and read the emotions of people you encounter. </p>
<p>Studies have <a href="http://jn.physiology.org/content/35/1/96">shown that</a> humans and other primates have evolved specialised brain areas that are dedicated to processing faces. While it is important to be able to detect a face in your peripheral vision, there would be no advantage to being able to discriminate between faces more accurately in the lower visual field than in other peripheral areas. Most of our encounters tend to be face to face, after all. </p>
<p>When we tested the same people again using faces, this hypothesis turned out to be correct too. We found that our subjects were no better in the lower visual field than elsewhere, and were actually slightly better at discriminating faces which were shown to the left. This apparent curiosity is probably due to the fact that humans’ face-specific brain area is located in the right cortical hemisphere. As with other brain functions, the right side of the brain controls the left side of the body, so this is what you would expect. </p>
<h2>Face/off</h2>
<p>As a control in our experiment, we also tested our subjects on faces with internal features removed – eyes, noses, mouths and so forth. Having reduced the face to a shape in this way, we speculated that our subjects would now perceive them more accurately in the lower field of vision than the other peripheral areas. This is exactly what we found. </p>
<p>It suggests there is an evolutionary advantage to processing an object shape below the centre of your vision – picking up berries on an ancient forest floor without taking your eyes away from potential predators, for instance. But there is little advantage, and a great deal of cost in terms of brain power, to extend this to all sorts of different object classes including faces.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/94028/original/image-20150907-1992-1crvhdx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/94028/original/image-20150907-1992-1crvhdx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/94028/original/image-20150907-1992-1crvhdx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94028/original/image-20150907-1992-1crvhdx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94028/original/image-20150907-1992-1crvhdx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94028/original/image-20150907-1992-1crvhdx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94028/original/image-20150907-1992-1crvhdx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94028/original/image-20150907-1992-1crvhdx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chin, chin.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&autocomplete_id=&search_tracking_id=ybLweI5fvdYDxbfh5T3plQ&searchterm=wine%20dinner&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=299004980">Everything</a></span>
</figcaption>
</figure>
<p>So next time you enjoy a glass of wine over dinner, you might feel safe in the knowledge that your visual senses have evolved to allow you to successfully pick up the glass without directly looking at it. Just remember to keep it on the table below your eyes. Put it on a shelf above eye level and there’s a much greater chance that the wine ends up all over the table – or worse.</p><img src="https://counter.theconversation.com/content/47175/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The middle part of our vision sees in a much higher resolution than at the peripheries. But that’s just the beginning …Gunter Loffler, Professor of Optometry, Glasgow Caledonian UniversityGael Gordon, Senior Lecturer, Vision Sciences, Glasgow Caledonian UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/68072012-05-24T03:16:15Z2012-05-24T03:16:15ZOut of sight, but still in mind: the mysteries of peripheral vision<figure><img src="https://images.theconversation.com/files/11008/original/h3wjwb98-1337818898.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Could your brain be anticipating what's there before you even turn your eyes?</span> <span class="attribution"><span class="source">Joe Fakih Gomez Photography</span></span></figcaption></figure><p>As you read this article your eyes will move so the words fall on the central part of your vision. This region is called the <a href="http://en.wikipedia.org/wiki/Fovea_centralis">fovea</a> and it has excellent resolution when compared to your peripheral vision.</p>
<p>Vision in the periphery is much better at detecting moving objects and subtle differences in luminance. These factors can be beneficial if a rock is hurtling in your direction, say, or if you’re playing football.</p>
<p>So why does the fovea have a higher resolving power than our peripheral vision? Well, it’s all about the number of <a href="http://en.wikipedia.org/wiki/Neuron">neurons</a> – cells in the brain that process and transmit information through electrical and chemical signalling. There are many more neurons in the visual part of the brain dedicated to processing each visual degree of space at the centre of our vision, compared to periphery.</p>
<p>Our <a href="http://www.cs.utexas.edu/%7Enn/web-pubs/sirosh/pvc.html">primary visual cortex</a> – the part of the brain that receives visual information from the eyes – has a “map” of space, where adjoining neurons represent adjacent regions of space (this is known as a <a href="http://www.scholarpedia.org/article/Visual_map">“retinotopic map”</a> – see image below). This map has greater representation at the centre of our vision compared with the periphery.</p>
<p>In 2008, my colleagues and I <a href="http://web.mit.edu/bcs/nklab/media/pdfs/Williams.etal.N2008.pdf">published research in Nature Neuroscience</a> based on tests we’d done with <a href="http://www.fmrib.ox.ac.uk/education/fmri/introduction-to-fmri/introduction">functional Magnetic Resonance Imaging (fMRI)</a>, a form of brain imaging.</p>
<p>When doing a difficult discrimination task in the periphery (“Are these two objects the same or different?”) we found information about these objects is also present at the foveal region of primary visual cortex.</p>
<p>That is, information about objects in the periphery is being sent to the part of the brain responsible for processing the centre of your vision.</p>
<p>This was a very surprising finding, as the retinotopic mapping of the visual cortex means this region should only receive input from the fovea or central vision.</p>
<p>Our finding also suggested that, in addition to direct input from the world, our foveal cortex also receives information from the periphery via other visual neurons (“feedback”).</p>
<p>Neuroimaging studies have the notorious disadvantage of being correlational – that is, a causal relationship cannot be established. So we needed to look to another technique to support our findings.</p>
<p>After lengthy discussions with a colleague at Cardiff University, <a href="http://psych.cf.ac.uk/contactsandpeople/researchfellows/chambers.html">Dr Chris Chambers</a>, and thanks to the financial support of the Cardiff University International Collaboration Fund, I visited “sunny” Cardiff in 2008 to begin a three-year <a href="http://en.wikipedia.org/wiki/Transcranial_magnetic_stimulation">Transcranial Magnetic Stimulation (TMS)</a> study.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/11009/original/kpb4wz8p-1337820568.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/11009/original/kpb4wz8p-1337820568.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/11009/original/kpb4wz8p-1337820568.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=522&fit=crop&dpr=1 600w, https://images.theconversation.com/files/11009/original/kpb4wz8p-1337820568.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=522&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/11009/original/kpb4wz8p-1337820568.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=522&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/11009/original/kpb4wz8p-1337820568.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=656&fit=crop&dpr=1 754w, https://images.theconversation.com/files/11009/original/kpb4wz8p-1337820568.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=656&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/11009/original/kpb4wz8p-1337820568.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=656&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Retinotopic mapping shows the correlation between regions of our vision and the parts of the brain responsible.</span>
<span class="attribution"><span class="source">PLoS ONE</span></span>
</figcaption>
</figure>
<p>TMS uses a very strong magnet to induce an electrical current in a small region of the cortex. When a pulse is given from the TMS, it transiently disrupts the brain under the magnet. This allows us to look at whether an area of the brain is critical in a particular task.</p>
<p>When we disrupted the foveal visual cortex early – 100 milliseconds (ms) – after the peripheral objects appeared on a black computer screen, people’s ability to compare them was unaffected. This is what we’d expect if the fovea responds only to incoming information from central vision.</p>
<p>But if we gave the TMS later, specifically 350-400ms after the stimuli appeared, then TMS affected performance. A timecourse of less than half a second might sound like a rapid pace, but for the brain, this is very slow – akin to a stroll in the park rather than a sprint.</p>
<p>The sprint happens for the “feedforward” visual processing (i.e. the first sweep of information that travels through the brain), which is completed by about 100ms. So this timecourse for the involvement of foveal cortex in discriminating peripheral objects pointed clearly to a feedback mechanism. That is, information about objects in the periphery being fed back to the portion of the visual cortex that processes central vision.</p>
<p>How might such a feedback mechanism work?</p>
<p><a href="http://www.cns.nyu.edu/%7Ehupe/Nature_394_784.pdf">One take on it</a> is that information from higher regions of the brain (areas involved in cognitive or semantic processes) feeds back a sort-of first guess or estimate of what might be out there in the periphery. But all previous theories of feedback suggest the information should go back to the same region of the cortex as the original input – not to the foveal cortex. </p>
<p><a href="http://cercor.oxfordjournals.org/content/15/10/1570.full.pdf">A second theory</a> invokes the idea of a visual scratch-pad or high resolution buffer at the foveal region of visual cortex. The many neurons dedicated to processing visual information at the foveal region could provide extra power to process the information - a sort of supercomputer for vision. </p>
<p>The <a href="http://www.ncbi.nlm.nih.gov/pubmed/17093130">third major theory</a> comes from the area of <a href="http://en.wikipedia.org/wiki/Saccade">“saccadic updating”</a>. Quite simply, a saccade is a movement of the eyes (or other body part) to a new location. When our eyes saccade, our visual system basically shuts down so the image we see doesn’t look blurred. </p>
<p>During this period (the length of which is still unknown) the brain updates the visual information to reflect the new scene that will fall on our eyes.</p>
<p>Our data may be evidence that even before you move your eyes, information in the periphery is transferred to the foveal region of the visual cortex in anticipation. When your eyes land on the new scene, a “guess” about what you’re going to see is already there.</p>
<p>It’s not yet clear which of these theories is correct. What is clear is that the foveal region of the primary visual cortex is involved in much more than simply processing what we are currently looking at. Indeed, it may support a whole other facet of our conscious vision.</p><img src="https://counter.theconversation.com/content/6807/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Williams receives funding from the Australian Research Council and the National Health and Medical Research Council.</span></em></p>As you read this article your eyes will move so the words fall on the central part of your vision. This region is called the fovea and it has excellent resolution when compared to your peripheral vision…Mark Williams, Associate Professor, Queen Elizabeth II (ARC) Research Fellow, Department of Cognitive Science, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/7602011-06-23T02:44:15Z2011-06-23T02:44:15ZHold your horses – news just in on the speed of sight<figure><img src="https://images.theconversation.com/files/1603/original/horses.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Why do the legs of galloping horses appear as a blur?</span> <span class="attribution"><span class="source">Eadweard Muybridge, 1878</span></span></figcaption></figure><p>What’s the fastest thing you can see? Events that play out over a scale of minutes or seconds are easy to see. Events at much smaller timescales — milliseconds and shorter — can be entirely invisible to us. To see them, we have to perform a kind of temporal microscopy.</p>
<p>Magnification of time (to see the very fast in slow-mo) first became possible in California, in the area we now know as Silicon Valley. But this was long before the place became famous for its technology innovation. </p>
<p>It was the late 19th-century, and the area was occupied by oil wells, farming and winemaking. Most travel was by horse, and a common pastime was betting at the races. </p>
<p>Every punter was in it to win, and it was the quest of one particular horse owner, <a href="http://www.bookrags.com/biography/leland-stanford/">Leland Stanford</a>, to achieve faster paces that spurred new technologies for capturing time.</p>
<h2>The fight for full flight</h2>
<p>Watching a champion thoroughbred at a fast gallop, you’ll notice the horse’s legs are blurred. The same will be true in photographs taken of the horse. In the case of the photograph, the camera’s film (or electronic sensor in digital cameras) averages together the incoming light over time. </p>
<p>In the case of biological vision, processes in your retina and brain average over time the signals evoked by the light, yielding a similar blurred effect.</p>
<p>In the 19th century, from everyday experience watching horses, it was obvious to people that unaided vision was not up to seeing the details of a galloping horse’s gait. A question of much debate was whether the four legs of a galloping horse are ever off the ground all at once. </p>
<p>People just couldn’t see whether or not a horse was ever in full flight. Enter Leland Stanford – founder of Stanford University – who realised better understanding of a horse’s gait might lead to some advantages over the competition. </p>
<p>Stanford resolved to settle the issue of whether all four galloping legs were ever simultaneously off the ground. </p>
<p>At the time, photographers commonly took a photo by first covering the lens with their hat, initiating the exposure by lifting their hat off, and terminating it by putting the hat back. The “snapshot” — rapid opening and closing of a shutter — had not been invented. </p>
<p>With the long exposures invariably created by these early photographers, the various positions occupied by a galloping horse’s legs all combined together into a blur. It was impossible to determine whether the horse’s legs are off the ground simultaneously – the information had been obliterated by the temporal blur.</p>
<p>To achieve shorter exposures, Stanford sought out an Englishman named <a href="http://www.bookrags.com/biography/eadweard-muybridge/">Eadweard Muybridge</a>, who had lately gained renown with spectacular photographs of landscapes in the American West. After some effort, Muybridge rigged a contraption involving a spring and two boards that slipped past each other. </p>
<p>Muybridge’s device yielded a short, controlled exposure of film to light lasting perhaps a twentieth of a second. To create a series of images of Stanford’s galloping horse, Sallie Gardner, Muybridge lay out a whole battery of cameras and triggered them with trip-wires. </p>
<p>Muybridge’s result is displayed in the image at top of this article. The second and third images in the series show all four hooves of the horse off the ground. Thanks to simple advances in technology, a door had been opened onto the world of the too-fast-to-see.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/UrRUDS1xbNs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Stanford’s thoroughbred Occident was captured for posterity in 1878.</span></figcaption>
</figure>
<p>Muybridge’s stopped-motion photographs quickly became popular. And for those not so interested in horses but rather in the slowness of human sight, the functioning of the camera provided a simple model of human limitations. The explanation for our inability to see whether a horse is ever in full flight seemed obvious: temporal blur created by the visual machinery inside our heads.</p>
<h2>Brain blur</h2>
<p>Temporal blur is the correct explanation of some perceptual speed limits. Our inability to see the continual flicker of fluorescent lights is one example.</p>
<p>Fluorescent lights, even well-functioning ones and very likely including those above your head if you work in an office, flicker on and off at a rate of over 100 times per second, much too fast for vision to resolve. Instead of perceiving the flicker, we see the average of the on phase with the off phase. </p>
<p>This temporal brain blur occurs over a long enough duration that it may possibly be sufficient to explain the difficulty perceiving the relative positions of the legs during a fast gallop.</p>
<p>Still, temporal blur cannot be the whole answer to the puzzle of the horse’s hooves. Our vision fails not only when a horse is at a full gallop, but also when it merely trots. </p>
<p>When trotting, a horse’s legs typically travel slow enough that the legs are not perceived as a blur – we witness the whole swing of the legs’ trajectory back and forth. Yet still the unaided eye is not up to deciding whether all four legs are ever off the ground simultaneously. </p>
<p>It’s a strange feeling, seeing the legs and their motions very clearly, but not knowing at any instant where exactly they are relative to each other. There is no counterpart to this human failing in a camera. You may be able to experience this phenomenon in the movie shown below.</p>
<p>A photograph reflects a single temporal limit, the exposure duration set by the camera’s shutter mechanism. In contrast, visual processing in the human brain reflects a collection of mechanisms working at different rates. Laboratory experiments over the last 20 years have teased apart some of these mechanisms to reveal their distinct speed limits. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/c9rpXIdIvSU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">In the middle row, one can’t perceive whether at each moment the sets of lines are parallel or oppositely tilted.</span></figcaption>
</figure>
<p>This movie, I believe, makes manifest the slow mechanism in your head that prevents access to the simultaneous positions of the horses’ hooves. </p>
<p>When viewing the movie, you’ll see two sets of lines alternating between leftward and rightward tilted. The responsible perceptual mechanisms in your brain are easily fast enough to extract these oriented lines, even at the fast 12 pictures per second rate at which your computer should display the middle row of the movie. </p>
<p>Nevertheless, for that fast middle row, seeing whether the sets of lines are at each instant oppositely tilted or instead share their tilt is beyond our mental grasp. As with the horse’s hooves, here we cannot apprehend which things happen at the same time.</p>
<p>When we view a scene, subsequent to light hitting our retinas, our visual brains process local bits of the scene individually, rapidly extracting the shapes and colours present. These mechanisms do this without determining which shapes or colours occur at the same time elsewhere in the scene. Our laboratory results indicate that joining the elements — such as the horse’s hooves — in some cases requires a distinct process: a shift of visual attention. </p>
<h2>Calling sight to attention</h2>
<p>In its technical meaning, visual attention is a mental resource used to enhance processing of selected elements of the scene. Most often it enhances processing at the location where your eyes are pointed, but you can also select objects in the periphery of your vision. Many only notice this in the particular situations where one should avoid looking directly at something, such as when sharing an elevator with a stranger. </p>
<p>We can “check out” the stranger without looking directly, using shifts of our visual attention. Such shifts actually occur all the time, but normally attention flits about so automatically and rapidly that we don’t notice the movements. Scientists themselves have struggled to determine when shifts occur and what they do for our perceptions.</p>
<p>In our lab, to reveal the role of attention in determining the spatial relationships among objects in the scene, we used a display resembling two rings of coloured jellybeans. View the movie below from a forthcoming <a href="http://www.cell.com/current-biology/">Current Biology</a> article reporting our experiments.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/igpGZxxkCXo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Judging which colours are aligned is possible here, but impossible at faster speeds.</span></figcaption>
</figure>
<p>People in the experiment were required to keep their eyes fixed on the grey dot at the centre, to be sure that shifts of attention rather than of the eyes was responsible for any selective processing. Varying the spinning rate of the display, we performed a test to find the maximum speed at which attention could follow the discs. </p>
<p>At rotation rates above the attentional speed limit (which unfortunately can’t be displayed on a webpage), the discs and their colours were still easily perceived, but one could no longer apprehend which colours were adjacent. It was as if we had peeled back one layer of normal visual consciousness. </p>
<p>Together with the results of an additional attentional test, this phenomenon suggests that a shift of attention is required to mentally link adjacent elements. When the colour rings revolve faster than the speed limit on following them with attention, one continues to perceive the colours but cannot see which are adjacent. </p>
<p>The situation may be the same with the rapid swing of a trotting horse’s legs.</p>
<p>More than a century ago, Muybridge was able to slow down external visual events so that they could be scrutinised with our relatively slow perceptual processes. </p>
<p>While this yielded new insights into the physical world at the millisecond scale, neither Muybridge’s camera nor any subsequent device have succeeded in capturing the mental world at fine timescales. </p>
<p>But with traditional techniques of psychological experiments and a little ingenuity, we have begun to reveal the brief episodes of processing that form our visual experience.
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<p><em><strong>The research outlined in this story <a href="http://www.cell.com/current-biology/abstract/S0960-9822(11)00558-6">forms the basis of a new article in Current Biology</a>.</strong></em></p><img src="https://counter.theconversation.com/content/760/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alex O. Holcombe does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>What’s the fastest thing you can see? Events that play out over a scale of minutes or seconds are easy to see. Events at much smaller timescales — milliseconds and shorter — can be entirely invisible to…Alex O. Holcombe, Associate Professor, School of Psychology, and Australian Research Council Future Fellow, University of SydneyLicensed as Creative Commons – attribution, no derivatives.