tag:theconversation.com,2011:/us/topics/visual-sciences-77533/articlesVisual sciences – The Conversation2021-02-05T13:06:37Ztag:theconversation.com,2011:article/1516502021-02-05T13:06:37Z2021-02-05T13:06:37ZDo you see red like I see red?<figure><img src="https://images.theconversation.com/files/382552/original/file-20210204-14-a5xafl.jpg?ixlib=rb-1.1.0&rect=752%2C783%2C6122%2C3968&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It's disconcerting to think the way two people perceive the world might be totally different.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/man-and-woman-standing-in-a-gallery-space-with-royalty-free-image/839180292">Mads Perch/Stone via Getty Images</a></span></figcaption></figure><p>Is the red I see the same as the red you see?</p>
<p>At first, the question seems confusing. Color is an inherent part of visual experience, as fundamental as gravity. So how could anyone see color differently than you do?</p>
<p>To dispense with the seemingly silly question, you can point to different objects and ask, “What color is that?” The initial consensus apparently settles the issue.</p>
<p>But then you might uncover troubling variability. A rug that some people call green, others call blue. A <a href="https://en.wikipedia.org/wiki/The_dress">photo of a dress</a> that <a href="https://doi.org/10.1016/j.cub.2015.04.053">some people call blue and black, others say is white and gold</a>.</p>
<p>You’re confronted with an unsettling possibility. Even if we agree on the label, maybe your experience of red is different from mine and – shudder – could it correspond to my experience of green? How would we know?</p>
<p>Neuroscientists, <a href="https://scholar.google.com/citations?user=LNgp00MAAAAJ">including</a> <a href="https://scholar.google.com/citations?user=6I_zDKUAAAAJ">us</a>, have tackled <a href="https://mitpress.mit.edu/books/color-ontology-and-color-science">this age-old puzzle</a> and are starting to come up with some answers to these questions. One thing that is becoming clear is the reason individual differences in color are so disconcerting in the first place. </p>
<h2>Colors add meaning to what you see</h2>
<p>Scientists often explain why people have color vision in cold, analytic terms: Color is <a href="https://doi.org/10.1146/annurev-vision-091517-034231">for object recognition</a>. And this is certainly true, but it’s not the whole story.</p>
<p>The <a href="https://doi.org/10.1167/18.11.1">color statistics of objects</a> are not arbitrary. The parts of scenes that people choose to label (“ball,” “apple,” “tiger”) are not any random color: They are more likely to be warm colors (oranges, yellows, reds), and less likely to be cool colors (blues, greens). This is true even for artificial objects that could have been made any color.</p>
<p>These observations suggest that your brain can use color to help recognize objects, and might explain <a href="https://theconversation.com/languages-dont-all-have-the-same-number-of-terms-for-colors-scientists-have-a-new-theory-why-84117">universal color naming patterns across languages</a>. </p>
<p>But recognizing objects is not the only, or maybe even the main, job of color vision. In <a href="https://doi.org/10.1038/s41467-019-10073-8">a recent study</a>, neuroscientists Maryam Hasantash and Rosa Lafer-Sousa showed participants real-world stimuli illuminated by low-pressure-sodium lights – the energy-efficient yellow lighting you’ve likely encountered in a parking garage.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/382625/original/file-20210204-20-zdq64j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="people and fruit lit by yellow low sodium lights" src="https://images.theconversation.com/files/382625/original/file-20210204-20-zdq64j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/382625/original/file-20210204-20-zdq64j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=911&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382625/original/file-20210204-20-zdq64j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=911&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382625/original/file-20210204-20-zdq64j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=911&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382625/original/file-20210204-20-zdq64j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1145&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382625/original/file-20210204-20-zdq64j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1145&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382625/original/file-20210204-20-zdq64j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1145&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 eye can’t properly encode color for scenes lit by monochromatic light.</span>
<span class="attribution"><span class="source">Rosa Lafer-Sousa</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The yellow light prevents the eye’s retina from properly encoding color. The researchers reasoned that if they temporarily knocked out this ability in their volunteers, the impairment might point to the normal function of color information. </p>
<p>The volunteers could still recognize objects like strawberries and oranges bathed in the eerie yellow light, implying that color isn’t critical for recognizing objects. But the fruit looked unappetizing. </p>
<p>Volunteers could also recognize faces – but they looked green and sick. Researchers think that’s because your expectations about normal face coloring are violated. The green appearance is a kind of error signal telling you that something’s wrong. This phenomenon is an example of how <a href="https://doi.org/10.1111/j.1933-1592.2010.00481.x">your knowledge can affect your perception</a>. Sometimes what you know, or think you know, influences what you see. </p>
<p>This research builds up the idea that color isn’t so critical for telling you what stuff is but rather about its likely meaning. Color doesn’t tell you about the kind of fruit, but rather whether a piece of fruit is probably tasty. And for faces, color is literally a vital sign that helps us identify emotions like anger and embarrassment, <a href="https://www.sciencedirect.com/science/article/pii/S0889159116304986">as well as sickness</a>, as any parent knows. </p>
<p>It might be color’s importance for telling us about meaning, especially in social interactions, that makes variability in color experiences between people so disconcerting. </p>
<h2>Looking for objective, measurable colors</h2>
<p>Another reason variability in color experience is troubling has to do with the fact that we can’t easily measure colors.</p>
<p>Having an objective metric of experience gets us over the quandary of subjectivity. With shape, for instance, we can measure dimensions using a ruler. Disagreements about apparent size can be settled dispassionately.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/382374/original/file-20210203-16-14psnr2.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="spectral power distribution of various wavelengths of light" src="https://images.theconversation.com/files/382374/original/file-20210203-16-14psnr2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/382374/original/file-20210203-16-14psnr2.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382374/original/file-20210203-16-14psnr2.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382374/original/file-20210203-16-14psnr2.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382374/original/file-20210203-16-14psnr2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382374/original/file-20210203-16-14psnr2.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382374/original/file-20210203-16-14psnr2.png?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"></a>
<figcaption>
<span class="caption">The spectral power distribution of a 25-watt incandescent lightbulb illustrates the wavelengths of light it emits.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Spectral_power_distribution_of_a_25_W_incandescent_light_bulb.png">Thorseth/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>With color, we can measure proportions of different wavelengths across the rainbow. But these “spectral power distributions” do not by themselves tell us the color, even though they are <a href="https://doi.org/10.1017/S0140525X03000013">the physical basis for color</a>. A given distribution can appear different colors depending on context and assumptions about materials and lighting, as <a href="https://doi.org/10.1167/17.12.25">#thedress proved</a>.</p>
<p>Perhaps color is a <a href="https://aardvark.ucsd.edu/color/hatfield.html">“psychobiological” property</a> that emerges from the brain’s response to light. If so, could an objective basis for color be found not in the physics of the world but rather in the human brain’s response? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/382371/original/file-20210203-20-1agq2g7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="cross section of retina with different cell types" src="https://images.theconversation.com/files/382371/original/file-20210203-20-1agq2g7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/382371/original/file-20210203-20-1agq2g7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382371/original/file-20210203-20-1agq2g7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382371/original/file-20210203-20-1agq2g7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382371/original/file-20210203-20-1agq2g7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382371/original/file-20210203-20-1agq2g7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382371/original/file-20210203-20-1agq2g7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cone cells in the eye’s retina encode messages about color vision.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/eye-anatomy-rod-cells-and-cone-cells-royalty-free-illustration/1091261988">ttsz/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>To compute color, your brain engages <a href="https://doi.org/10.1146/annurev-vision-091517-034202">an extensive network of circuits</a> in the cerebral cortex that <a href="https://doi.org/10.1146/annurev-vision-121219-081801">interpret the retinal signals</a>, taking into account <a href="https://journals.sagepub.com/doi/full/10.1177/1073858419882621">context and your expectations</a>. Can we measure the color of a stimulus by monitoring brain activity?</p>
<h2>Your brain response to red is similar to mine</h2>
<p>Our group used magnetoencephalography – MEG for short – to monitor the tiny magnetic fields created when nerve cells in the brain fire to communicate. We were able to classify the response to various colors using machine learning and then <a href="https://doi.org/10.1016/j.cub.2020.10.062">decode from brain activity the colors</a> that participants saw.</p>
<p>So, yes, we can determine color by measuring what happens in the brain. Our results show that each color is associated with a distinct pattern of brain activity.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/382764/original/file-20210205-13-17w8sz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person seated in MEG machine looking at screen with color projection" src="https://images.theconversation.com/files/382764/original/file-20210205-13-17w8sz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/382764/original/file-20210205-13-17w8sz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=378&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382764/original/file-20210205-13-17w8sz4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=378&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382764/original/file-20210205-13-17w8sz4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=378&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382764/original/file-20210205-13-17w8sz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=475&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382764/original/file-20210205-13-17w8sz4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=475&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382764/original/file-20210205-13-17w8sz4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=475&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Researchers measured volunteers’ brain responses with magnetoencephalography (MEG) to decode what colors they saw.</span>
<span class="attribution"><span class="source">Bevil Conway</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>But are the patterns of brain response similar across people? This is a hard question to answer, because one needs a way of perfectly matching the anatomy of one brain to another, which is really tough to do. For now, we can sidestep the technical challenge by asking a related question. Does my relationship between red and orange resemble your relationship between red and orange? </p>
<p>The MEG experiment showed that two colors that are perceptually more similar, as assessed by how people label the colors, give rise to more similar patterns of brain activity. So your brain’s response to color will be fairly similar when you look at something light green and something dark green but quite different when looking at something yellow versus something brown. What’s more, these similarity relationships are preserved across people. </p>
<p>Physiological measurements are unlikely to ever resolve metaphysical questions such as “what is redness?” But the MEG results nonetheless provide some reassurance that color is a fact we can agree on.</p><img src="https://counter.theconversation.com/content/151650/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bevil R. Conway receives funding from the Intramural Research Program (IRP) of the National Eye Institute (NEI). </span></em></p><p class="fine-print"><em><span>Danny Garside receives funding from the Intramural Research Program (IRP) of the National Eye Institute (NEI). </span></em></p>Neuroscientists tackling the age-old question of whether perceptions of color hold from one person to the next are coming up with some interesting answers.Bevil R. Conway, Senior Investigator at the National Eye Institute, Section on Perception, Cognition, and Action, National Institutes of HealthDanny Garside, Visiting Fellow in Sensation, Cognition & Action, National Institutes of HealthLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1518642020-12-17T11:54:45Z2020-12-17T11:54:45ZVisual illusion that may help explain consciousness – new study<figure><img src="https://images.theconversation.com/files/375371/original/file-20201216-21-qtywpt.jpg?ixlib=rb-1.1.0&rect=39%2C49%2C3255%2C2415&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The brain is a mystery.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-conceptual-image-large-stone-shape-1032541603">Orla/Shutterstock</a></span></figcaption></figure><p>How much are you conscious of right now? Are you conscious of just the words in the centre of your visual field or all the words surrounding it? We tend to assume that our visual consciousness gives us a rich and detailed picture of the entire scene in front of us. The truth is very different, as our discovery of a visual illusion, <a href="https://journals.sagepub.com/doi/abs/10.1177/0956797619847166">published in Psychological Science</a>, shows.</p>
<p>To illustrate how limited the information in our visual field is, get a deck of playing cards. Pick a spot on the wall in front of you and stare at it. Then take a card at random. Without looking at its front, hold it far out to your left with a straight arm, until it’s on the very edge of your visual field. Keep staring at the point on the wall and flip the card round so it’s facing you. </p>
<p>Try to guess its colour. You will probably find it extremely difficult. Now slowly move the card closer to the centre of your vision, while keeping your arm straight. Pay close attention to the point at which you can identify its colour. </p>
<p>It’s amazing how central the card needs to be before you’re able to do this, let alone identify its suit or value. What this little experiment shows is how undetailed (and often inaccurate) our conscious vision is, especially outside the centre of our visual field.</p>
<h2>Crowding: how the brain gets confused</h2>
<p>Here is another example that brings us a little closer to how these phenomena are investigated scientifically. Please focus your eyes on the + sign on the left, and try to identify the letter on the right of it (of course you know already what it is, but pretend for the moment that you do not):</p>
<figure class="align-center ">
<img alt="Image of a plus sign on the left and an A on the right." src="https://images.theconversation.com/files/375363/original/file-20201216-21-j0k2iw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/375363/original/file-20201216-21-j0k2iw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=254&fit=crop&dpr=1 600w, https://images.theconversation.com/files/375363/original/file-20201216-21-j0k2iw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=254&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/375363/original/file-20201216-21-j0k2iw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=254&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/375363/original/file-20201216-21-j0k2iw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=319&fit=crop&dpr=1 754w, https://images.theconversation.com/files/375363/original/file-20201216-21-j0k2iw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=319&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/375363/original/file-20201216-21-j0k2iw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=319&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Illusion 1.</span>
<span class="attribution"><span class="source">TCUK</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>You might find this a bit tricky, but you can probably still identify the letter as an “A”. But now focus your eyes on the following +, and try to identify the letters on the right:</p>
<figure class="align-center ">
<img alt="Image of a plus sign on the left and JRWTS on the right." src="https://images.theconversation.com/files/375365/original/file-20201216-21-2r5tet.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/375365/original/file-20201216-21-2r5tet.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=242&fit=crop&dpr=1 600w, https://images.theconversation.com/files/375365/original/file-20201216-21-2r5tet.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=242&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/375365/original/file-20201216-21-2r5tet.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=242&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/375365/original/file-20201216-21-2r5tet.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=305&fit=crop&dpr=1 754w, https://images.theconversation.com/files/375365/original/file-20201216-21-2r5tet.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=305&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/375365/original/file-20201216-21-2r5tet.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=305&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Illusion 2.</span>
<span class="attribution"><span class="source">TCUK</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>In this case, you’ll probably struggle to identify the letters. It probably looks like a mess of features to you. Or maybe you feel like you can see a jumble of curves and lines, without being able to say precisely what’s there. This is called “crowding”. Our visual system sometimes does OK at identifying objects in our peripheral vision, but when those objects are placed near other objects, it struggles. This is a shocking limitation on our conscious vision. The letters are clearly presented right in front of us. But still our conscious mind gets confused. </p>
<p>Crowding is a hotly debated topic in <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/tht3.28">philosophy</a>, <a href="https://www.sciencedirect.com/science/article/pii/S0042698907005561">psychology</a> and <a href="https://www.sciencedirect.com/science/article/pii/S1053811914001207?casa_token=Otxpma-h-OkAAAAA:nx1W6cQmP_J7CA39qrpNMz0JobXbEhV4FOdWPkvAv894pvSI6Gaxvcq8wE2LjKKqFiFrIvc">neuroscience</a>. We’re still not sure why crowding happens. One popular theory is that it’s a failure of what’s called “<a href="https://jov.arvojournals.org/article.aspx?articleid=2192655">feature integration</a>”. To understand feature integration, we will need to pick apart some of the jobs that your visual system does. </p>
<p>Imagine you are looking at a blue square and a red circle. Your visual system does not just have to detect the properties out there (blueness, redness, circularity, squareness). It also has to work out which property belongs to which object. This might not seem like a complicated task to us. However, in the visual brain, this is no trivial matter. </p>
<p>It takes a lot of complicated computation to work out that circularity and redness are properties of one object at the same location. The visual system needs to “glue” together the circularity and the redness as both belonging to the same object, and do the same with blueness and squareness. This gluing process is feature integration. </p>
<figure class="align-center ">
<img alt="Image of a road with autumn trees in the periphery." src="https://images.theconversation.com/files/375338/original/file-20201216-21-5exemd.jpg?ixlib=rb-1.1.0&rect=49%2C90%2C5472%2C3284&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/375338/original/file-20201216-21-5exemd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/375338/original/file-20201216-21-5exemd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/375338/original/file-20201216-21-5exemd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/375338/original/file-20201216-21-5exemd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/375338/original/file-20201216-21-5exemd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/375338/original/file-20201216-21-5exemd.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">How much of the periphery do we perceive?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/road-through-algonquin-provincial-park-fall-492095068">Inga Locmele/Shutterstock</a></span>
</figcaption>
</figure>
<p>According to this theory, what happens in crowding is that the visual system detects the properties out there, but it can’t work out which properties belong to which object. As a result, what you see is a big mess of features, and your conscious mind cannot differentiate one letter from the others.</p>
<h2>New illusion</h2>
<p>Recently, we have discovered a new visual illusion that has raised a host of new questions for fans of crowding. We tested what happens when three of the objects are identical, for example in the following case:</p>
<figure class="align-center ">
<img alt="Image of a plus sign on the left and TTT on the right." src="https://images.theconversation.com/files/375364/original/file-20201216-13-pslac.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/375364/original/file-20201216-13-pslac.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=213&fit=crop&dpr=1 600w, https://images.theconversation.com/files/375364/original/file-20201216-13-pslac.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=213&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/375364/original/file-20201216-13-pslac.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=213&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/375364/original/file-20201216-13-pslac.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=267&fit=crop&dpr=1 754w, https://images.theconversation.com/files/375364/original/file-20201216-13-pslac.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=267&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/375364/original/file-20201216-13-pslac.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=267&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Illusion 3.</span>
<span class="attribution"><span class="source">TCUK</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>What do you see when you look at the +? We found that more than half of people said that there were only two letters there, rather than three. Indeed, follow-up work seems to indicate that they’re pretty confident about this incorrect judgment.</p>
<p>This is a surprising result. Unlike normal crowding, it’s not that you see a jumble of features. Rather, one whole letter neatly drops away from consciousness. This result fits poorly with the feature integration theory. It’s not that the visual system is detecting all of the properties out there, but just getting confused about which properties belong to which objects. Rather, one whole object has just disappeared.</p>
<p>We don’t think that a failure of feature integration is what’s going on. Our theory is that this illusion is due to what we call “redundancy masking”. In our view, the visual system can detect that there are several of the same letter out there, but it doesn’t seem to calculate correctly how many there are. Maybe it’s just not worth the energy to work out the number of letters with high precision.</p>
<p>When we open our eyes, we effortlessly get a conscious picture of our environment. However, the underlying processes that go into creating this picture are anything but effortless. <a href="https://theconversation.com/three-visual-illusions-that-reveal-the-hidden-workings-of-the-brain-80875">Illusions</a> like redundancy masking help us unpick how these processes work, and ultimately will help us explain consciousness itself.</p><img src="https://counter.theconversation.com/content/151864/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bilge Sayim receives funding from the French Agence Nationale de la Recherche (ANR), I-SITE ULNE, and the Swiss National Science Foundation (SNSF).</span></em></p><p class="fine-print"><em><span>Henry Taylor 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>How we perceive what’s going on in the periphery can reveal a lot about our conscious minds.Henry Taylor, Birmingham Fellow in Philosophy, University of BirminghamBilge Sayim, Research Scientist in Psychology, Université de LilleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1242622019-10-16T21:57:59Z2019-10-16T21:57:59ZThe blind and visually impaired can help researchers by getting their genes tested<figure><img src="https://images.theconversation.com/files/297399/original/file-20191016-98666-1lztb57.jpg?ixlib=rb-1.1.0&rect=73%2C154%2C4691%2C2906&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Gene therapy trials may mean that the next generation of children born with inherited eye diseases have treatment options.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Blind and partially sighted people no longer have to wait passively for a research breakthrough in hope of treatment options. In fact, people living with genetic eye conditions can now actively drive vision research forward — by enrolling in a patient registry and getting their genes tested.</p>
<p>There are <a href="https://www.who.int/news-room/fact-sheets/detail/blindness-and-visual-impairment#targetText=Globally%2C%20it%20is%20estimated%20that,people%20are%20blind%20(1).">2.2 billion people living with visual impairment globally</a>. Some are living with inherited retinal diseases that are progressive and can lead to complete blindness. Up until recent years, blind and visually impaired people were told that no treatment is available. This is changing as <a href="https://doi.org/10.2174/1566523217666171116170040">genetic testing is paving the way for a surge of gene therapies</a>.</p>
<h2>My passion for vision research is personal</h2>
<p>My <a href="https://doi.org/10.1523/JNEUROSCI.1647-16.2016">doctoral dissertation</a> at the University of British Columbia was on drug therapy for <a href="https://doi.org/10.1016/S0140-6736(06)69740-7">retinitis pigmentosa</a>. This progressive, blinding eye condition is the most common type of inherited retinal disease. </p>
<p>In people affected by retinitis pigmentosa, the light sensing cells in their retina — photoreceptors — die early. Unlike skin cells that regenerate, the body does not make more photoreceptors once they are damaged.</p>
<p>As a vision scientist affected by retinitis pigmentosa, I am passionate about finding the truth about the disease. Why do photoreceptors die? How can we stop it? How can science and medicine help?</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/297405/original/file-20191016-98657-6y043a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/297405/original/file-20191016-98657-6y043a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=371&fit=crop&dpr=1 600w, https://images.theconversation.com/files/297405/original/file-20191016-98657-6y043a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=371&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/297405/original/file-20191016-98657-6y043a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=371&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/297405/original/file-20191016-98657-6y043a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=466&fit=crop&dpr=1 754w, https://images.theconversation.com/files/297405/original/file-20191016-98657-6y043a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=466&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/297405/original/file-20191016-98657-6y043a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=466&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Retinitis pigmentosa causes the light sensing cells, or photoreceptors, in a retina to die early.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>When I was 12 years old, I realized while at summer camp that my night vision was disappearing. In the last two decades, I lost my peripheral vision, contrast sensitivity and depth perception.</p>
<p>I worked in <a href="http://moritzlab.ophthalmology.ubc.ca/">Dr. Orson Moritz’s lab</a> at the UBC department of ophthalmology and visual sciences, which focuses on research using tadpoles that contain known human mutations for retinitis pigmentosa to understand the disease. </p>
<p><a href="https://www.iheart.com/podcast/269-eyes-on-success-rad-29372511/episode/1734-retinitis-pigmentosa-research-aug-16-29372697/">I made an alarming discovery in our animal model</a>: knowing the genetic cause of retinitis pigmentosa is <a href="https://www.jneurosci.org/content/37/4/1039">vital for treatment with one class of drugs — histone deacetylase inhibitors</a>. These determine how genes are switched “on” or “off.”</p>
<p>A similar <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4225157/">study in mice</a> showed that the same drug reacted differently to variations in a single mutant gene that also causes retinitis pigmentosa.</p>
<p>Treating retinitis pigmentosa is like extinguishing fire. To stop a fire, you need to know whether it’s water-based or grease-based. If you try to use water to stop a grease fire, the damage gets worse.</p>
<h2>Enrol in a patient registry</h2>
<p>Blind and visually impaired people can advocate for eye health by enrolling in a patient registry. Participation in a registry <a href="https://doi.org/10.1371/journal.pone.0220983">benefits researchers by offering more information</a> about the disease.</p>
<p>In Canada, individuals can self-refer to <a href="https://www.fightingblindness.ca/">Fighting Blindness Canada’s</a> secure, clinical <a href="https://www.fightingblindness.ca/patient-registry/">patient registry</a>. This database is dedicated to connecting people living with retinal eye diseases to clinical trials and research.</p>
<p>When a gene therapy trial arises, researchers draw participants from this database. Since <a href="https://doi.org/10.2174/1566523217666171116170040">gene therapy aims to correct an underlying genetic mistake in DNA that causes disease</a>, knowing the genetic cause of a disease is a criteria for most gene therapy trials.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"897651303010140160"}"></div></p>
<p>Globally, other registries include <a href="https://www.fightingblindness.org/my-retina-tracker">My Retina Tracker</a> in the United States, <a href="https://www.fightingblindness.ie/how-we-can-help/research/target-5000s/">Target 5000</a> in Ireland, <a href="https://myeyesite.org.uk/">MyEyeSite</a> in the United Kingdom, the <a href="https://www.scgh.health.wa.gov.au/Research/DNA-Bank">Australian Inherited Retinal Disease Registry</a> and <a href="http://jegc.org/">Japan Eye Genetics Consortium</a>. In New Zealand, <a href="https://unidirectory.auckland.ac.nz/profile/a-vincent">Dr. Andrea Vincent</a> has established the Genetic Eye Disease Investigation Unit. There is even a <a href="https://www.bcmregistry.org/">Blue Cone Monochromacy Patient Registry</a> for one rare eye condition.</p>
<h2>Blossoming gene therapy trials</h2>
<p>In the last two decades, the number of gene therapy trials has blossomed. Currently, <a href="https://sph.uth.edu/retnet/">250 genes on inherited retinal diseases have been identified</a>. In <a href="http://ir.sparktx.com/news-releases/news-release-details/european-commission-approves-spark-therapeutics-luxturnar#targetText=LUXTURNA%20was%20approved%20by%20the,(%20FDA%20)%20in%20December%202017%20.">2017, the first gene therapy for inherited retinal disease</a> — Luxturna — was <a href="https://www.fda.gov/vaccines-blood-biologics/cellular-gene-therapy-products/luxturna">approved by the United States Federal Drug Administration</a>.</p>
<p>To date, there are trials for: <a href="https://www.clinicaltrials.gov/ct2/results?term=gene+therapy&cond=retinitis+pigmentosa&Search=Apply&recrs=a&age_v=&gndr=&type=&rslt=">retinitis pigmentosa</a>; <a href="https://clinicaltrials.gov/ct2/results?term=Gene+Therapy&cond=Usher&Search=Apply&recrs=a&age_v=&gndr=&type=&rslt=">Usher syndrome</a>, a condition that involves hearing and vision loss;
<a href="https://www.clinicaltrials.gov/ct2/results?term=gene+therapy&cond=Achromatopsia&Search=Apply&recrs=a&age_v=&gndr=&type=&rslt=">achromatopsia</a>, a disease that causes colour blindness; <a href="https://www.clinicaltrials.gov/ct2/results?term=Gene+Therapy&recrs=ab&cond=X-linked+Retinoschisis&rank=1#rowId0%22%22">X-linked retinoschisis</a>, a dystrophy that causes splitting of the retina and affects mostly in males; and <a href="https://www.clinicaltrials.gov/ct2/results?term=gene+therapy&cond=Age+Related+Macular+Degeneration&Search=Apply&recrs=a&age_v=&gndr=&type=&rslt=">age-related macular degeneration</a>, the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2623053/">third-largest cause of vision loss worldwide</a>, caused by the interplay between <a href="https://doi.org/10.1146/annurev-genom-090413-025610">genetics and environment</a>.</p>
<p>Enrolment in a patient registry and genetic testing advance the design of gene therapy trials. This in turn benefits blind and visually impaired people. </p>
<p>Research advancement is a concerted effort across the globe — blind and partially sighted people should know they have the power to push it forward.</p>
<p>[ <em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/ca/newsletters?utm_source=TCCA&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/124262/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ruanne Vent-Schmidt's doctoral research project was funded by Fighting Blindness Canada.
Ruanne Vent-Schmidt is the Specialist in Peer Support, Advocacy and Research Communications at the Canadian National Institute for the Blind.</span></em></p>Gene therapy trials for inherited retinal diseases are blossoming. Blind and partially sighted people are helping to advance the research.Ruanne Lai, PhD Candidate, Cell & Developmental Biology, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.