The Evolution of (Un)Fairness

The human sense of fairness is an evolutionary puzzle; why do we put so much value on what we receive relative to others?  One answer to this question emerges from studying other species.  Although fairness itself is hard to study, it can be translated empirically into how individuals respond to different reward distributions, and studying other species’ reactions can tell us something about the evolution of our own behavior. Indeed, humans are not alone in disliking inequity; many species protest receiving less than a partner for the same task, and this tendency occurs primarily in species that cooperate, indicating a link between the two behaviors. I hypothesize that this response acts as a partner choice mechanism that allows individuals to recognize good cooperative partners.  However, a full sense of fairness requires not only this, but also that individuals notice and seek to equalize outcomes to their own detriment.  There is less evidence of this latter reaction in nonhuman species, although it has been documented in our closest relatives, the apes. If the inequity response function as a partner choice mechanism, this reaction likely reflects an attempt to forestall one’s partner’s dissatisfaction and its negative impact on future cooperation. Therefore, it is likely that the evolution of this response, combined with advanced abilities at inhibition and planning, allowed the development of a full sense of fairness in humans, which allows for the extensive cooperation we see in our own species.

A Monkey and Cooperative Skills | Science Nation