Buy Parajumpers Gobi,Parajumpers JacketsDuring the evolution of cooperation it may have become critical for individuals to compare their own efforts and pay-offs with those of others. Negative reactions may occur when expectations are violated. One theory proposes that aversion to Buy Parajumpers Gobi inequity can explain human cooperation within the bounds of the rational choice model, and may in fact be more inclusive than previous explanations. Although there exists substantial cultural variation in its particulars, this 'sense of fairness' is probably a human universal that has been shown to prevail in a wide variety of circumstances. However, we are not the only cooperative animals, hence inequity aversion may not be uniquely human. Many highly cooperative nonhuman species seem guided by a set of expectations about the outcome of cooperation and the division of resources. Here we demonstrate that a nonhuman primate, the brown capuchin monkey (Cebus apella), responds negatively to unequal reward distribution Parajumpers Jackets in exchanges with a human experimenter. Monkeys refused to participate if they witnessed a conspecific obtain a more attractive reward for equal effort, an effect amplified if the partner received such a reward without any effort at all. These reactions support an early evolutionary origin of inequity aversion.Comment inOn inequity aversion in nonhuman primates. [J Comp Psychol. 2006]On inequity aversion in nonhuman primates.Silberberg A, Roma PG, Ruggiero AM, Suomi SJ. J Comp Psychol. 2006 Feb; 120(1):76. Animal behaviour: inequity aversion in capuchins? [Nature. 2004]Animal behaviour: inequity aversion in capuchins?Henrich J. Nature. 2004 Mar 11; 428(6979):139; discussion 140. Animal behaviour: fair refusal by capuchin monkeys. [Nature. 2004]Animal behaviour: fair refusal by capuchin monkeys.Wynne CD. Nature. 2004 Mar 11; 428(6979):140; discussion 140.