Researchers at the Duke University Medical Centre have identified a particular brain region that predicts whether people tend to be selfish or altruistic.
"Although understanding the function of this brain region may not necessarily identify what drives people like Mother Teresa, it may give clues to the origins of important social behaviors like altruism," said study investigator Dr. Scott A. Huettel, a neuroscientist at the Brain Imaging and Analysis Centre.
Altruism describes the tendency of people to act in ways that put the welfare of others ahead of their own, but why some people choose to act altruistically is unclear, says lead study investigator Dharol Tankersley, a graduate student in Huettel's laboratory.
In the study, published in the online edition of Nature Neuroscience, the researchers used functional magnetic resonance imaging (fMRI) to scan the brains of 45 people while they were either playing a computer game or watching the computer play the game on its own.
Tankersley said that a region of the brain called the posterior superior temporal sulcus was activated to a greater degree when people perceived an action, that is, when they watched the computer play the game than when they acted themselves. This region lies in the top and back portion of the brain and is generally activated when the mind is trying to figure out social relationships.
Thereafter, the participants were as more or less altruistic, based on their responses to questions about how often they engaged in different helping behaviours. The fMRI scans showed that increased activity in the posterior superior temporal sulcus strongly predicted a person's likelihood for altruistic behaviour.
The researchers believe that altruistic behaviour may originate from how people view the world rather than how they act in it.
"We believe that the ability to perceive other people's actions as meaningful is critical for altruism," Tankersley said.
Boffins also believe that the study of brain systems that allow people to see the world as a series of meaningful interactions may further help understand disorders, such as autism or antisocial behaviour, that are characterised by deficits in interpersonal interactions.
Tankersley said that his team was working on to study the development of this brain region early in life, as such information might help determine how the tendencies toward altruism are established.