Animal behaviour: fair refusal by capuchin monkeys.

Brosnan and de Waal report that capuchin monkeys show evidence of a sense of fairness or 'inequity aversion' because they rejected a less preferred reward when they saw a partner monkey receive a preferred reward for the same task. However, this does not show that monkeys are averse to inequity, only that they reject a lesser reward when better rewards are available. There are risks inherent in seeking anthropomorphic explanations for non-human behaviour.