For example, in one experiment a group of subjects was given £20 and told that any money they held at the end of the experiment would be multiplied up to 10 times.

In the course of the experiment the subjects interacted with other individuals. They were told that if they decided to keep the money, these individuals would be subjected to mild electric shocks, but if they gave up the money, no shocks would be administrated.

Women were less likely than men to be subjected to shocks, suggesting an aversion to harming females - even when this came at the subjects’ own financial expense. While both female and male subjects were less likely to shock women than men, women in particular were less willing to shock other women.