In our brain there is an area that controls prosocial behavior, as researchers found in a special patient group. Accordingly, the “Basolateral Amygdala”, part of the limbic system, calibrates how generously we behave towards strangers and friends. This brain region weighs up between selfishness and altruism and also takes into account how close we are in individual fellow human beings. In people with whom this brain area is damaged, this gradation is so radical that it almost only share with close friends, as the study showed. The findings could help in the future to help people with social behavioral problems.
People are social beings: we support each other and generally behave prosocial. But we don’t treat all of our fellow human beings the same. For example, we encounter family and friends more benevolently than strangers. Why this is and which neural mechanisms control our social behavior in the brain has not yet been fully clarified.
Subregion of the Amygdala in sight
A team led by Tobias Kalenscher from the Heinrich Heine University Düsseldorf (HHU) has now investigated how generous we behave towards close and less close people and what happens in our brain. For this purpose, the researchers worked with five patients in South Africa who suffer from the extremely rare “Urbach-Wiethe syndrome” (UWD). Less than 150 affected people are known to this hereditary disease worldwide. You have a changed emotional life and social behavior. For example, you cannot conclude from facial expressions on the emotions expressed in it.
The reason for this is that the so -called basolateral amygdala (BLA for short) is damaged by those affected. “This brain region assumes that they are decisive for compassionate behavior towards other people,” says Kalscher. To check this connection, the researchers carried out game experiments with the patients and 16 healthy control persons. The participants received money that they could distribute to eight other people. You should decide for yourself how much you give up close friends, acquaintances, neighbors or strangers. Family members as the next caregiver were not allowed in the game in order to be able to better examine the gradation of social proximity.
“The results were clear: people with Bla damage were just as generous as healthy control persons. But as soon as it was about people who had a lower emotional relationship, they behaved more carefully,” reports co-author Luca Lüpken from the HHU. The subjects with Urbach-Wiethe syndrome gave foreign and loose acquaintances significantly less money than people with an intact basolateral amygdala. “The willingness of the UWD participants to share decreased more with increasing social distance,” writes the team.
Brain region controls the degree of generosity
Kalscher and his colleagues conclude from the experiment that this brain region is not fundamentally necessary to act altruistic or prosocial. But the basolateral amygdala controls how generous we are closer to a person depending on the perceived. If this form of calibration is missing, those affected only show prosocial behavior when it comes to the best friends – people with great emotional proximity. In contrast, when dealing with strangers and acquaintances without Bla, the natural tendency to put your own well -being over the well -being of others dominates. This decision is then processed via other neural circuits and brain regions.
Accordingly, there is an area in our brain that controls our social behavior and the balance keeps between selfishness and altruism: basolateral amygdala. “Social decisions are not only shaped by our upbringing or culture, but they are also deeply anchored in the mechanisms of our brain,” says Kalscher. In the future, this knowledge could help to better understand other diseases in which social decisions have changed – e.g. autism or psychopathy. “Perhaps in the future it will be possible to develop targeted therapies to help people with social behavioral problems to control their decision -making processes better,” said Kalscher.
Source: Tobias Kalenscher (Heinrich-Heine-Universität Düsseldorf) et al.; Proceedings of the National Academy of Sciences (PNAS), DOI: 10.1073/PNAS.2500692122