The findings showed that the striatum -- an active decision-maker located in the middle of the brain and responsible for the assessment of reward -- is more strongly activated in female brains during prosocial decisions than during selfish decisions.

"The reward and learning systems in our brains work in close cooperation. Studies show that girls are rewarded with praise for prosocial behaviour or helping behaviour instead of selfish behaviour," said Alexander Soutschek, post-doctoral student at the University of Zurich, Switzerland.

"With this in mind, the gender differences could best be attributed to the different cultural expectations placed on men and women," Soutschek added.

The study, published in the journal Nature Human Behavior, also revealed that when the researchers applied medication to the participants, both the males and females behaved differently. Under these conditions, women behaved more selfishly, while men became more prosocial. 

"These results demonstrate that the brains of women and men also process generosity differently at the pharmacological level," Soutschek added.