In the tests 34 female participants were divided into two groups.
Those in the ’empathy’ group witnessed an actor receive painful electric shocks.
In the second ‘reciprocity’ group participants were paired up with actors who paid money so the participant received fewer shocks.
Their brains were scanned while participants were asked to split money between themselves and another person.
In the empathy group, the other person receiving the money was sometimes the partner they saw shocked and in the reciprocity group, they were sometimes the partner who had paid for the participant to receive fewer shocks.
At other times, participants were simply asked to split the cash between themselves and a neutral person who didn’t receive shocks or do anything nice.
The researchers could divide the group into empathy-driven altruists and reciprocity-driven altruists, base