Surprisingly for such a universal experience, pain is profoundly misrepresented by common myths about what it is and what it means. These are rooted in dualistic models: the body as a simple machine and the mind, distinct, receiving input from and sending orders to the machine. But pain emerges from recursive interaction of the brain and the body and constant adjustment of the system according to the organism’s priorities.
So what are some of the most widespread misconceptions about how pain works? Here are five of the biggest myths.
1. Pain is not a sensation
Describing pain as a sensory experience, like touch or temperature, is misleading, even though painful levels of touch and temperature are continuous with innocuous sensations. Pain is inherently threatening, and is processed not as “here is an interesting change in conditions” but as “do something to stop this now!”
A major cause of death for our ancestors and in some societies now were (are) infections following injury. Pain reminds us to take care of wounds, to conserve resources. Emotion and motivation are essential components of pain, as was found by a neurologist who tried to build an artificial pain signalling system for people with leprosy.
Nor is pain the opposite of pleasure: that is merely a linguistic convention in some cultures. Reducing pain is rewarding: probably an evolutionary belt and braces to ensure that healing remains a priority once safety is ensured. Pleasure can help distract from pain – as can unpleasant stimuli – if the pain is not very threatening and attention-demanding, as in experimental settings, or if patients feel confident in their own resources and others’ care.
2. Pain is not an index of damage
In clinical settings, the patient’s report of pain is often compared with pathology, as if pain should be proportional to tissue damage. But the function of pain is to alert us to injury or threats to physical integrity, not represent that injury or threat.
So although everyday pains often have visible causes or visible damage – the stubbed toe, the paper cut – we do not look for damage as a cause of most everyday headaches, or abdominal pains. Neuropathic pain is generated by malfunctioning nerves which cannot be observed by ordinary methods.
The sensitivity of the nervous system to pain is a product of input from skin, muscle, organs and of all the relevant resources of the brain – memory, expectations, fears, context, emotional state and much more – integrated in the spinal cord and in the brain. It is this system which generates chronic pain long after healing, or in the absence of any injury, with multiple mechanisms amplifying and even generating pain, and those that could inhibit it suppressed.
3. Pain without obvious cause isn’t ‘psychosomatic’
Pain “disproportionate” to identified pathology is often deemed psychological, but the judgement of proportionality of pain is limited by our knowledge and technologies. This merely uses the “psycho-” prefix as a category for all that we cannot understand.
The concept of psychosomatic pain makes untenable distinctions between mind and body and proposes only the vaguest mechanisms, usually varieties of pre-scientific hydraulic analogies (psyche “overflowing” into soma). The theoretical backing for the psychosomatic origin of physical symptoms is wholly inadequate. We should also be suspicious when theories, such as that of psychosomatic pain, are applied predominantly to disadvantaged groups: people from other cultures, women, and those with existing psychological problems.
The belief that people commonly exaggerate or fake pain for sympathy rests on evidence that emotional comfort mitigates pain, in children and adults. But this does not mean that the pain was not “real”, any more than when a grieving person is temporarily comforted by kindness while still being recognised as genuinely distressed. We easily discount the pain of others, and construct imaginative explanations for their pain.
4. Lab studies of pain tell us little
Healthy volunteers, subjected to mild levels of experimental pain, have a trivial pain experience.
Pain that is mild, brief, expected and willingly undergone is not a model for unexpected, incomprehensible, severe and possibly unremitting pain, particularly in someone who believes him or herself to be physically or psychologically vulnerable.
5. Pain does not always lead to empathy
Though people can read pain in others’ expressions, this does not always elicit empathy and help. In the lab, volunteer onlookers are usually empathic to some degree, but this is by no means uniquely human: [rodent empathy is well established](http://www.cell.com/trends/cognitive-sciences/abstract/S1364-6613(11)00278-6?_returnURL=http%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS1364661311002786%3Fshowall%3Dtrue?_returnURL=http%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS1364661311002786%3Fshowall%3Dtrue).
Outside the lab, we are often suspicious about others’ pain, in case they take advantage of our compassion. This even operates in clinical settings: medical personnel routinely underestimate patients’ pain and therefore undertreat it.
Worse, in some circumstances, people are deliberately cruel, causing pain to family members, to those in their care, or to those they denigrate, perhaps as non-human. Is the ideal solution, of preventing torture and cruelty, impossible? Far too few studies address the behaviour of perpetrators and the context of pain seriously enough to bring us nearer stopping it.