Capuchin monkeys against Fair Trade

Fair Trade consists of paying selected producers more than the market price. The extra cost is paid by consumers willing to help those producers. As a result the selected producers earn more than their equally productive neighbors. Capuchin monkeys oppose Fair Trade (from Conservation Finance, reporting on a study by Sarah Brosnan and Frans de Waal):

Pairs of brown capuchin monkeys (Cebus apella) were placed next to each other and trained to exchange a token with human handlers to receive a reward, in most cases a piece of cucumber. Partners of capuchins who made the swap either received the same reward (a cucumber slice), or a better reward (a grape, a more desirable food), for the same amount of work or, in some cases, for performing no work at all. Capuchins who witnessed unfair treatment and failed to benefit from it often refused to conduct future exchanges, would not eat the cucumbers they received for their labors, and in some cases, threw food rewards at human researchers.