Why do we help others? Scientists say this part of the brain drives our altruism

The Star

15-05-2025

The amygdala is not directly responsible for generosity, but plays an essential regulatory role. — AFP
Why do we help others? This question, as old as human society itself, is now being re-examined by an international research team.
Their findings, published in the journal Proceedings of the National Academy of Sciences (PNAS) point to a specific area of the brain.The basolateral amygdala, nestled in the heart of the limbic system, could well play a decisive role in our social behaviour.
Led by Professor Tobias Kalenscher of Heinrich Heine University in Dusseldorf, in collaboration with researchers from the universities of Lausanne, Utrecht and Cape Town, this study is based on the observation of a group of patients with Urbach-Wiethe disease.
This rare genetic condition specifically damages the basolateral amygdala, without affecting other parts of the brain.The scientists wanted to determine how a specific difference in this region of the brain influenced prosocial behaviour.
In order to observe these mechanisms at work, the researchers went to Namaqualand, an isolated region of South Africa home to a community with an unusual concentration of cases of Urbach-Wiethe syndrome.
Although this rare disease has only about 150 recorded cases worldwide, a significant number of sufferers live in this specific area.
On site, scientists have conducted several experiments following a protocol based on a tool well known to behavioural economists: "the dictator game.'
In this game, participants receive a sum of money and must freely decide how much they wish to offer to another person, whether a relative, neighbour or stranger.
The results speak for themselves. Patients with Urbach-Wiethe syndrome show a level of generosity towards their loved ones that is comparable to that of other people.
However, their attitude changes radically when it comes to more distant people.Their generosity drops significantly, as if their brain is unable to adjust their behaviour according to the nature of the emotional bond.
"Individuals with BLA damage were just as generous toward people they were close to as healthy control participants. However, as soon as it came to individuals with whom they had less of an emotional connection, they were notably more selfish,' explains Luca M. Lupken, doctoral student at Heinrich Heine University and co-author of the study, in a press release.
The amygdala is not directly responsible for generosity, but plays an essential regulatory role by adjusting our behaviour according to the degree of social proximity.In other words, it does not orient our morality per se, but influences a person's choice of who they decide to behave altruistically towards.
When it does not function properly, this modulation mechanism can lead to self-centered behaviour. Alterations in this area of the brain could also provide insights into certain disorders, such as autism or psychopathy, in which social decisions frequently deviate from established norms.
For Professor Tobias Kalenscher, these discoveries resonate far beyond the laboratory."Social decisions are not only shaped by our upbringing or culture. They are in fact also strongly anchored in the mechanisms of our brain,' he asserts.
This new understanding of the drivers of altruism could pave the way for targeted interventions capable of restoring a form of social equilibrium among individuals in difficulty.
By refining our knowledge of the link between neuronal structure and behaviour, science could not only discover new therapeutic levers, but also fuel broader reflection on the conditions for a supportive and inclusive society. – AFP Relaxnews