The primate trait that increases reproductive success when living in a complex society is the cooperative coalitions.
The primates have variations in social structures and organisation. High competition can be seen among the male primates as they want to copulate with as many females as possible to increase the chances to producing more offspring. Coalition formation is the cooperation in a competitive context, where one primate intervenes in an ongoing conflict between two parties to support one side to improve their dominance based status, which improves the mating success.
It can be seen in many primate species. Generally there are fewer females than males in the primate population so males are compelled to cooperate for the limited resources.
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The Hawthorne effect (also referred to as the observer effect) explains that individuals modify an aspect of their behavior in response to their knowledge of being observed. In this study students changed their eating place during the observation period.
