Some people have neurological quirks that give them extraordinary perceptual powers. What can we learn from them?
Photo by John Lund/Gallery Stock
Michael Banissy is a lecturer in psychology at the Department of Psychology at Goldsmiths, University of London.
Ordinary people with superior perceptual skills walk among us, absorbing information from the everyday world which is debarred to the rest of us. We can’t spot them, but they can pick up the faintest traces of smell or taste. They might see coloured auras that correspond to the expressed emotions of others. Some of them can even experience the pain or pleasure felt by other people. As one of these unlikely ‘superhumans’, Mary, a 53-year-old therapist, explains: ‘If I see pain inflicted, I feel pain myself. If I see gentleness in a touch of a hand, I get pleasure from the softness and love I can feel in that touch.’ In neurological circles, Mary is known as a mirror-touch synaesthete. She literally feels what other people feel.
Psychological research I've conducted with colleagues at University College London and the University of Sussex indicates that one to two people out of a hundred experience mirror-touch sensations from childhood. We've noticed that, for such people, observing pain evokes the most intense experience. One of the mirror-touch synaesthetes we’ve worked with, whom I’ll call Alan, has to work hard to reassure himself that he’s not actually experiencing the things he feels. ‘When I see someone being touched, I have to consciously remind myself that I am not being touched myself,’ he says. ‘When I see pain, it’s the same, except the feeling is more intense; it draws my attention more [and] makes me think, “Oh, I am watching pain and it is not there.”’
Such abilities might seem like miraculous gifts, not unlike the supernatural powers given to the character Lydia in the US television series Heroes — the ability to feel the emotions, thoughts, hopes, and desires of others — or the extraordinary sensory powers bestowed on the streetwise teens in the British comedy-drama Misfits. But these abilities often require careful managing. Mary, for example, finds it impossible to see violence depicted on screen. ‘I hate it when my husband watches violent movies,’ she told us. ‘I cannot watch them, because I feel overloaded. This is obviously not a pleasant experience and it’s a downside to my synaesthesia.’ But the sensations are not always overwhelming. ‘The upside,’ said Mary, ‘is that I also experience the nice touches, the caresses and the hugs. None of the experiences last for long, and for that I am grateful.’
The mirrored feeling is experienced in exactly the same part of the body — a finger for a finger, an arm for an arm, an eye for an eye.
Ironically, just as we might imagine what a sensory-enhanced life might be like for a mirror-touch synaesthete, they, too, often try to imagine what a life — seemingly benumbed — must be like for the rest of us. For Alan, ‘Living with mirror-touch is at its most interesting when I stop and observe it, and think how fascinating it is that other people don’t experience it.’ But when his condition fails to fascinate him, it can be burdensome: ‘It becomes a bit overwhelming at times, especially in crowded places.’
Terms such as ‘overwhelming’ or ‘fascinating’ crop up a good deal when we talk to mirror-touch synaesthetes about their everyday experiences. One man I interviewed reported feeling cold in his fingertips whenever I touched a glass filled with ice. While mirrored thermal sensations are rare, they do share with mirrored touch sensations the quality of anatomical specificity. The mirrored feeling is experienced in exactly the same part of the body as the person actually experiencing the cold, heat or pain feels it — a finger for a finger, an arm for an arm, an eye for an eye.
For most, the mirrored-touch sensation directly mirrors what they see — observing someone touch the left side of the face evokes in them a sensation on the right side of the face. But for a few, the mirrored sensation is anatomically mapped — if they see someone touch the left side of their face they’ll feel it on the left side of their own face. So while some synaesthetes treat observed touch as though looking directly in the mirror, others rotate their perspective to that of the observed person.
With the help of functional brain imaging, we have begun to understand why some individuals possess this particular ability. We asked a group of mirror-touch synaesthetes to watch videos of other people being touched, and gave the same task to a group of people without mirror-touch synaesthesia. When we compared the brain scans of the two groups, we learnt that anyone, synaesthete or not, recruits parts of the brain involved in experiencing touch themselves (the mirror-touch system). Our brains mirror observed experiences. In people with mirror-touch synaesthesia, this empathetic system is over-excitable, and can activate rapidly to reach a threshold that allows them to experience tactile sensations literally.
But we still don’t understand the precise mechanisms leading to this pattern of brain activity. Experimental findings seem to suggest that we all show a greater tendency to mirror observed touch when the person experiencing the event is more similar to ourselves. And this raises the possibility that the networks involved in distinguishing representations of oneself from others act as a gate to levels of excitability in those brain regions involved in mirroring.
It is possible that, in people who experience mirror-touch sensations, the levels of excitability of the neural networks governing the ability to distinguish oneself from others leads to a change in normal mirroring mechanisms. Simply put, the brain of an individual who experiences mirror-touch sensations effectively treats the body of another person as though it were her own.
Mirror-touch synaesthetes might be viewed as society’s natural empathisers — people wired to excel at putting themselves in another person’s shoes. This can be a delight, or a burden. Or a peculiarly human, if amplified, mix of the two.
In studies I’ve undertaken with Jamie Ward, professor of psychology at the University of Sussex, we’ve found that people who experience mirror-touch show heightened levels of emotional reactive empathy — that is, the ability to understand and share the affective states or feelings of others. Another study I’ve been involved in, published in the Journal of Neuroscience (2011), indicates that individuals with mirror-touch are significantly better than the rest of us at recognising the facial emotions of others, though not necessarily better at recognising who those people are. Mirror-touch synaesthetes outperform control subjects when tasked with naming the facial emotions of people photographed smiling, fretting, frowning, puzzling, gurning and so forth. We were able to rule out any suggestion that their better scores were the result of greater effort, or that they were better with faces generally, because when tested on their ability to name the people in the photographs, those with mirror-touch performed no better than those without.
Super-recognisers will hide their memory of long-ago encounters to avoid discomfiting people who never even registered them.
One of the ways we understand other peoples’ emotions is by putting ourselves in their place. To understand if someone is angry, we simulate what it is like to experience anger ourselves. If someone is sad, we simulate sadness. When these simulation mechanisms are over-excitable, as in mirror-touch synaesthesia, they can spill over and facilitate other abilities, such as emotion-recognition, which also use mirroring processes. In this sense, people with mirror-touch can tell us how much the degree to which we simulate the experiences of others can contribute to broader social-perception abilities, such as emotion-recognition and empathy.
It is not just synaesthetes who possess apparent superpowers. ‘Supertasters’, for example, perceive stronger taste sensations from a variety of everyday substances, including alcohol, coffee and green tea.
To supertasters, sugar tastes sweeter, the bitterness of, say, Brussels sprouts, is exaggerated, carbon dioxide bubbles in fizzy drinks are more pronounced, and there is more burn from oral irritants such as alcohol. On the whole, supertasting might be more of an ‘irritating power’ than a ‘superpower’. Indeed, some supertasters experience less enjoyment from food and drink and are therefore less likely to indulge, which might explain why female supertasters at least are thinner than non-tasters (people at the other end of the tasting spectrum). At root, supertasters have a greater number of fungiform papillae (the mushroom-shaped dots on the front of your tongue) and taste buds. There are no known complex neural pathways involved in this particular ability.
But it’s a different matter with super-recognisers. These are a rare group of individuals who excel in the ability to remember faces. First reported in 2009 by researchers at Harvard University and Dartmouth College, these are people who really never forget a face. They can recognise people whom they might have seen only a few times in their lives or, as Brad Duchaine, one of the Dartmouth College research team, puts it, ‘an extra they saw in a movie years before’.
Such people can identify casual staff that served them years earlier, a waitress at a motorway inn they passed through, a car-park attendant they once glimpsed, or a fellow department store shopper with whom they never interacted. The difficulties that this super-ability might cause in social settings are easy enough to imagine, and many super-recognisers will hide their memory of long-ago encounters to avoid discomfiting people who never even registered them.
Work is ongoing to determine just how common super-recognisers are, but there is some evidence to suggest that they can put their skills to good use. For example, the Metropolitan Police Service in London used super-recognisers in their ranks to help identify individual rioters during the 2011 riots across the capital.
So, some people can feel the sensations of others, some can pick up on the faintest emotions, and some can excel in their memory. What about the rest of us? Are these abilities simply out of our reach or are there ways in which we might enhance these faculties in ourselves?
With supertasting, it would seem that biological factors stand in our way, but what about developing a superior memory, or the ability to excel in emotion sensitivity? This is an avenue that many labs are now starting to pursue — testing the extent to which we can improve perception and memory by using training and techniques that help us to modulate brain activity in order to aid performance. By studying people with superior psychological skills we can begin to unpack key processes that aid their abilities, processes which, in turn, could be used to help the rest of us become a bit more ‘superhuman’.
5 June 2013