There are some who say that helping others is its own reward, and many biologists would agree. The fact that selfless acts give us a warm glow is evident from personal experience and neurological studies, which find that good deeds trigger activity in parts of the brain involved in feelings of reward. But feeling food by being good isn't just the province of humans - monkeys too get a kick out of the simple act of giving to their fellow simians.
At the Yerkes National Primate Research Center, Frans de Waal's team of scientists have been investigating the selfless side of eight brown capuchin monkeys. Each monkey was given a choice between two differently coloured tokens. Both would earn it a rewarding piece of apple but only one token would net a slice for a second monkey sitting in an adjacent transparent compartment.
The chooser would benefit equally no matter ...
