A rat that could use a hand

Humans like to believe they are special. With the Christmas season ahead, compassion is on ourmind. We often feel that compassion makes humans noble, it seems to elevate us above the other, seemingly selfish animals. This stance is engraved in our idiom: the word 'humane', which up to the 18th century simply meant human, now stands for compassionate, while the word 'bestial', which originally meant related to animals, now stands for brutality and cruelty. Recent research now questions this assumption: animals, yes even rats, seem to share the distress of others and take action to help them.

Sharing the emotions of others

A key element of human compassion is the sensitivity to other people's emotions. In the book "The Empathic Brain", I tell the story of how our lab and a handful of colleagues discovered that our brain is deeply empathic. Using functional magnetic brain imaging, we were able to show that when you see someone experiencing an emotion, be it disgust, pain or pleasure, brain regions become active that are normally active when you feel these same emotions. This indicates that witnessing what others feel does not simply make you realize abstractly what they feel, but that your brain is actually wired to let you feel what they feel. The joys and sorrows of others become our own. Your fate and the fate of those people around you are actually deeply connected by the invisible threads of empathy. People that are more empathic show more of these vicarious activations; psychopathic criminal show less of this activity.

Empathy drives us to help

Sharing the emotions of others is a powerful experience. It makes us weep while watching a sad movie or rejoice with the victories of heroes. But what good is it for the people around us? What matters is that empathy motivates us to help others. If you see a crying victim of violence, you empathically suffer her pain. This vicarious pain is unpleasant, and to ease it you help the victim. If you can even get the victim to smile, her joy becomes yours. Psychopathic criminals that experience less empathy, seem to also lack this pro-social motivation

But what about rats?

This year (Atsak et al., 2011), we showed that if a rat witnesses another receive a mild electroshock, two things happen. The rat that receives the shock jumps then freezes. Freezing is a typical expression of fear in rats; if they see a cat they freeze. This makes it harder for the cat to hear or see them, and often saves their life. When they get a shock, they do the same. To our surprise, the other rat, that simply witnesses the reaction of the shocked rat, also froze - as if she had received a shock herself. A number of other research groups have found similar phenomena (see Panksepp & Lahvis, 2011 for a review). Rats therefore seem to also share the emotions of their fellow rats. But would that sharing drive them to help others, like it does in humans?

A paper (Bartal et al., 2011) by the group of Peggy Mason at the University of Chicago to appear Friday in Science shows for the first time, that under certain circumstances, it does. In this experiment, a rat was restrained in a small little cage in the middle of larger arena—a distressing experience. Another rat was free to move, and had a chance to come and free the captive rat by opening the door of its cage. Opening this door takes some effort, and it took rats a while to find out how to open it. In contrast to the misconception that rats would be selfish animals, the free rats were seen putting considerable effort into finding ways to open the door and free their captive compatriot. In an additional experiment, they gave the free rat an opportunity to snack on chocolate chips instead of freeing the captive. A selfish rat would be expected to first eat all the chips, then either do nothing, or free the captive. In contrast the rats were seen freeing the captive before eating all of the chips and then sharing the remainder of the chips with the liberated rat.

A word of caution

The history of mankind is filled with examples of exceptional braveness. During the holocaust, some helped Jews at the peril of their own lives. The experiments mentioned above are far from exploring similar situations: The rats had little reasons not to help, and only gave up a couple of minutes and chocolate chips. Whether rats might be willing to risk their lives to help another remains very unclear. It also remains unclear what the rats were feeling while helping. In humans, some people only help to alleviate their own vicarious distress, while others seem to do it because they feel truly compelled to help. These alternative motives are distinguished by giving potential helpers a chance to leave the situation. Leaving reduces the discomfort of witnessing someone's distress, but does not help the other person. People that choose to leave are, therefore, primarily seeking to reduce their own distress. Those that stay and help might be truly compassionate. Which is true in rats remains to be explored. That said, evidence for emotional sharing and helping behaviour in rats shows us that there may be more similarities between animals and humans than we suspected. We might not be the only moral animal. Rather than hurting our self-esteem, these findings should reassure us. If we share empathy and the motivation to help others with rats, these motives must be deeply engraved into our biology and brain architecture. Neither men nor rats are angels: both species also experience greed and envy, and will hurt and even kill others in some situations. But the motivation to help others seems to be a biological reality.

A thought for Christmas

A Christmas gift of compassion

So if you are still looking for Christmas presents, what better time to reflect on compassion? Consider giving your friends some food for thought. The new science of empathy has generated some very good books. One of them is The Empathic Brain ($12 as a softcover, or $2.99 as a kindle ebook). Through the detour of animal research and brain science, biology is discovering a new side to human nature

Praise for The Empathic Brain: "An exciting read for anyone interested in the gentler side of our species" (Prof. Frans de Waal, Emory). "Christian Keysers’ explanation of how mirror neurons make us social is a masterpiece". (Prof. Dick Swaab, Netherlands Institute for Neuroscience). "Though many have written about mirror neurons, this book outshines them all" (Prof. Mark Hauser, Harvard University). "What sets The Empathic Brain ahead of all other books in my opinion, is that it is such a great authoritative read" (The Psychologist).

The Empathic Brain

How mirror neurons help you understand others.
Christian Keysers, Ph.D.

Christian Keysers, Ph.D., heads a lab at the Netherlands Institute for Neuroscience. He was part of the team that discovered mirror neurons.

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