Loved-ones feel each other's pain, study suggests

Humans are hardwired to feel empathy, suggests a new imaging study showing that certain pain-processing regions of the brain light up when a loved-one is hurt.

But no one actually "feels" the physical pain of the ones they love. The UK researchers suggest that empathy is the result of our brain running a virtual simulation that represents only part of the other person's experience.

"That' s probably why empathy doesn't feel like pain in your hand," says Tania Singer, a neuroscientist at the University College London, who led the study. "It feels like when you anticipate your own pain. Your heart races, your emotions are engaged. It's like a smaller copy of the overall experience," – reports &to=http://www.newscientist.com' target=_blank>NewsCientist

When someone says, "I feel your pain," it isn't just an expression of empathy, brain researchers say. It may be literally true.

The pain-sensing part of your brain switches on when you're aware that someone else is in pain, according to research published in today's issue of the journal Science. And the stronger you feel empathy for someone else's pain, the fiercer the activity in the pain-sensing regions of your brain.

Empathy, the ability to grasp the feelings of others, is one of humanity's most cherished traits. It's associated with the greatest humanitarians, social activists and philanthropists, as well as the most insightful novelists and artists. For decades, evolutionary biologists have argued over why humans and other animals risk their lives to help others. According to the "selfish gene" hypothesis, altruism make little sense - at first glance, anyway - because the altruist risks sacrificing not only his life but his genes and, hence, his genetic contribution to posterity or the gene pool.

But others have offered cunning arguments for why, under certain circumstances, altruism makes more sense. For example, by one interpretation, it makes genetic sense for an elderly male to rescue a healthy young female relative - one who is genetically close to him - because her fertile years are still ahead of her, while he's less likely to bear offspring, informs &to=http://www.sfgate.com' target=_blank>SFGate.com

A team from University College London found that merely knowing your loved one is suffering is enough to activate pain centres in the brain. The study, publised in Science, is based on 16 couples. The researchers measured activity in the brain while painful stimulation was applied to the woman's right hand - or to the right hand of her partner. They found that watching the pain suffered by a partner was enough to trigger activity in some - but not all - of the brain's pain centres.

Simply watching pain being inflicted was enough to trigger an empathetic response, making the witness aroused and emotional. In effect, the brain flinches when it sees someone in pain in the same way that we might wince. This is the same kind of response triggered by anticipating that you are about to be hurt. Women who reported the strongest feelings of empathy experienced the greatest brain activity.