When it was discovered that adopted 3 year old twin girls Binh and Phuoc had a potentially fatal genetic disorder, Michael Wagner did what any father would do: he donated a portion of his liver to his child. Unfortunately, there was only enough tissue for one of his daughters, and their mother was not a match. The gut-wrenching decision of which daughter would receive the liver tissue was given to the doctors. A devastating plea to the public ensued: is anyone willing to donate a portion of his or her liver to help a complete stranger?
This is a perfect example of altruism. In a biological context, altruism is a behavior that is detrimental to that individual, but benefits another. Evolutionary biology typically explains such behaviours as a form of kin selection (helping out someone who shares some of the same genes as you). More broadly, as a cultural concept altruism is the concern for the welfare of others; selflessness.
Donating a piece of yourself is certainly the definition of selflessness. But what are the chances someone might be willing to undergo a potentially life-threatening surgery to donate an organ to someone they’ve never met? That level of altruism is simply remarkable.
Marsh and colleagues certainly thought so, and the team sought to better understand what’s going on in the brain of such extraordinary altruists. Are there neurological differences in people that engage in extreme acts of life-saving altruism? Ironically, the authors developed their hypothesis based on what research has taught us about psychopaths.
Psychopathy is a condition characterized by antisocial behaviours, including a lack of compassion, empathy, guilt, and remorse. The authors hypothesize the existence of a social spectrum, with psychopathy on one end, and extreme altruism on the other.
In psychopaths the amygdala, a region of the brain associated with emotional reactions, is both smaller and less responsive to the facial expression of fear. Being able to identify fear in other people is a marker of sensitivity, compassion and empathy towards others.
This suggests a potential neural mechanism that might explain some of the behaviours characteristic of psychopaths. Perhaps the amygdala of extreme altruists, the authors hypothesized, is larger and more responsive.
A group of altruistic kidney donors and matched controls were shown angry, fearful, and neutral facial expressions. Subjects were administered a functional MRI, allowing researchers to examine levels of activity in specific regions of the brain. The amygdala of extreme altruists was both significantly larger, and more responsive to fearful facial expressions than controls.
Marsh and colleagues take care to point out that these neurological differences only partly explain extreme altruists; personality, social, and cultural differences are also important components.
Two months after her sister received her father’s liver tissues, Binh Wagner successfully underwent a liver transplant after receiving tissue from an anonymous donor. Nearly 500 people contacted the Toronto General Hospital to offer a portion of their liver. It’s nice to know that such people exist, to balance out the psychopaths.