The Science of Altruism

Post Reply New Topic

Biology has long struggled with the concept of altruism. There is now reasonable agreement that its purpose is partly to be nice to relatives (with whom one shares genes) and partly to permit the exchanging of favours. But how the brain goes about being altruistic is unknown. Dr Marsh therefore wondered if the brains of extreme altruists might have observable differences from other brains?and, in particular, whether such differences might be the obverse of those seen in psychopaths.

She and her team used two brain-scanning techniques, structural and functional magnetic-resonance imaging (MRI), to study the amygdalas of 39 volunteers, 19 of whom were altruistic kidney donors. (The amygdalas, of which brains have two, one in each hemisphere, are areas of tissue central to the processing of emotion and empathy.) Structural MRI showed that the right amygdalas of altruists were 8.1% larger, on average, than those of people in the control group, though everyone?s left amygdalas were about the same size. That is, indeed, the obverse of what pertains in psychopaths, whose right amygdalas, previous studies have shown, are smaller than those of controls.