Researchers from the University of Oxford and University College London have identified the part of the brain that learns prosocial behavior, and believe that weak activity in this region may contribute to antisocial and psychopathic personality disorders.

Prosocial behavior – which refers to actions that are intended to benefit others – is hugely important for the success of complex societies. As such, humans have had to evolve specific neural mechanisms that enable us to make decisions that aren’t for personal gain. However, levels of selflessness tend to vary across populations, with some people being highly empathetic towards others and some being rather more cold-hearted.

Empathy has been identified as a major driver of prosocial behavior, while a lack of empathy is associated with personality disorders such as psychopathy. To investigate the neural mechanisms linking empathy to prosocial behavior, scientists devised an experiment in which participants had to learn which symbols corresponded to a cash reward for themselves, and which resulted in these rewards being given to other people. Meanwhile, the team used functional magnetic resonance imaging (fMRI) to monitor their brain activity.

Describing the results in a statement, study co-author Patricia Lockwood explained that “a specific part of the brain called the subgenual anterior cingulate cortex was the only part of the brain that was activated when learning to help other people. Put another way, the subgenual anterior cingulate seems to be especially tuned to benefiting other people.”

Writing in the Proceedings of the National Academy of Sciences, the researchers confirm that this part of the brain was not activated when participants learned new behaviors for their own benefit, and only responded to prosocial learning. However, Lockwood insists that “this region of the brain was not equally active in every person.”

After assessing the empathy levels of each participant using a scientifically validated questionnaire, the authors discovered that empathy was strongly correlated with the speed with which people learned prosocial solutions, as well as strength of activity in their subgenual anterior cingulate cortex.

Extrapolating from this finding, the researchers claim that abnormally low levels of activity in this part of the brain may explain why some people have a lack of empathy or suffer from psychological conditions characterized by antisocial tendencies.