Feeling Your Pain

“I feel your pain” is often meaningless pablum, but for some people with unusual brain wiring it is literally true.

People with a condition called mirror-touch synesthesia experience the sensation of being touched when they see someone else being touched. (In other forms of synesthesia, one sensory experience—feeling or hearing, for instance—triggers a wholly different one, such as seeing. As a result, the estimated 1-in-200 people who have synesthesia see particular colors when they hear particular musical notes, or see shapes when they process aromas, or always see specific letters or numbers in the same particular color, so that a P is always lemon yellow and a 5 always mauve. One synesthete told me that a roast chicken in citrus sauce is perfectly cooked when it "looks pointed.”) A new study finds that mirror-touch synesthetes have an unusually strong ability to empathize with others. More than a mere curiosity, the finding hints that empathy may arise from the brain’s ability to feel what it sees.

In 2002 scientists established, with brain imaging, that synesthesia arises from crossed-wiring. In synesthetes who see colors when they hear spoken words, the brain region that processes color in standard brains is also activated by words. Neuroscientists’ best guess is that synesthesia arises when the developing brain fails to prune the millions of extra connections, or synapses, that we are all born with and that standard brains eliminate in childhood; the result is a rich web of circuitry that connects touch areas and visual areas, or sound regions with vision regions, or other sensory combinations.

Before the current experiment, scientists knew of only one mirror-touch synesthete. But Michael Banissy and Jamie Ward of University College London managed to find 10 others. The scientists first established that when mirror-touch synesthetes watch another person being touched, their brain’s primary and secondary somatosensory cortex are activated; these are the same regions that become active when you are touched yourself. The scientists then touched the synesthetes on their left cheek or right, and then their right hand or left; at the same time the synesthetes watched as another person was touched. As expected, they felt the touch that they saw, and if they saw someone touched on the left cheek but were themselves touched on the right, it got confusing: it took them longer to report “left” or “right,” and they made more mistakes. Hence the literalness of “I feel what you’re feeling.”

But does that translate into greater empathy? The scientists ran one additional test, a standard measure of empathy called emotional reactivity. Compared to people without mirror-touch synesthesia, the synesthetes scored significantly higher, the UCL scientists report in Nature Neuroscience. That supports the idea that empathy reflects a literal sympathy, or same-feeling. In those of us with standard brains, a system of what are called mirror neurons fire when we see someone else doing something—reaching for a glass, stubbing their toe. It’s not as powerful as the crossed wires of mirror-touch synesthesia, but it may be the basis for the empathy we do manage to conjure.

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