In the study, published online in the journal Current Biology, participants on two separate visits received a pill containing either a placebo or tolcapone, a drug that prolongs the effects of dopamine, a brain chemical associated with reward and motivation in the prefrontal cortex. Participants then played a simple economic game in which they divided money between themselves and an anonymous recipient. After receiving tolcapone, participants divided the money with the strangers in a fairer, more egalitarian way than after receiving the placebo.