 We have had a taste above of the way in which scientists might propose to explain our particular moral attitudes or judgments by appeal to specific evolutionary causes as filtered through cultural developments. Human beings have a strong, emotionally-laden sense of basic fairness, resentment of cheaters, and a desire that they be punished, all of which finds expression in both cultural norms and individual moral judgments. You might experience such feelings if you’ve been the victim of a scam, morally condemning the perpetrators. And some of these psychological traits may have analogues in other species. For example, Sarah Brosnan and Frans de Waal (2014) argue that “evidence indicates that [inequity aversion, i.e., negative reactions to unequal rewards for similar tasks] is widespread in cooperative species under many circumstances”--though some have disputed this and offered alternative hypotheses to explain the behavior, based on further research (Engelmann, Clift, Herrmann, and Tomasello 2017).[5] In the simplest case, an animal protests when it sees a companion receive a superior reward for a similar task, as in a well-known study with brown capuchin monkeys, though similar effects have now been observed even in non-primates, such as dogs and crows. In the more complex case, chimpanzees sometimes react negatively to inequity even where they are the ones receiving the greater reward. A natural evolutionary hypothesis for the simpler case is that such a disposition protected against ‘wasting’ cooperative efforts where they were not fitness-enhancing. Similarly, a natural explanatory hypothesis for the more complex form of inequity aversion is that it evolved in creatures with sufficient predictive capacities and emotional control because it preserved beneficial cooperative relationships that could be threatened by such inequities, thus proving fitness-enhancing on the whole given the benefits of continued cooperation (Brosnan and de Waal, 2014). All of this might suggest good prospects for causal explanation of human moral traits in terms of evolved psychological traits. Indeed, Brosnan and de Waal explicitly hypothesize that the evolved complex response observed in champanzees is what “allowed the development of a complete sense of fairness in humans, which aims not at equality for its own sake but for the sake of continued cooperation” (Brosnan and de Waal, 2014).