The evolution of human normativity: the role of prosociality and conformity

Normative behavior is a human universal that is intimately linked to morality. Morality is an adaptation to the specifically human subsistence niche of hunting and gathering, which is skill-intensive and therefore relies on transmission of opaque knowledge and involves critical interdependence, reliance on coordinated division of labor, and synchronized collective action. This lifestyle requires the presence of a variety of emotions that coevolved with it as the proximate mechanisms enabling this adaptive function. The high-urgency feel to many of these emotions reflect their functional importance: it serves to give them priority over other motivations. It is also what, to us, and makes them recognizable as moral. The key components of human morality are (1) prosocial emotions, and (2) an urge to conform. Together, they produce the urge to comply with moral norms. Normativity is thus an integral part of human morality. It evolved when two preferences came together. Strong informational conformity, needed to enable the transmission of opaque knowledge, was already present in the anthropoid primate ancestors of hominids and hominins. The added component evolved with the evolution of strong interdependence: a strong concern for one’s reputation and fear of punishment, and thus strongly prosocial emotions. Thus, the emergence of normativity in our ancestors does not require a special explanation: it was an automatic byproduct of the emergence of moral behavior in our ancestors. Introduction An evolutionary biologist confronted with any persistent behavior, for instance food choice and diet selection, would develop the working hypothesis that it represents an adaptation molded by natural selection. The evolutionary approach, moreover, presupposes that function and mechanism fit together (Tinbergen 1963): natural selection for a particular adaptive function automatically implies selection on particular mechanisms. Thus, the presence of particular emotions must reflect the presence of evolved functions. This evolutionary approach is not necessarily incompatible with the presence of major cultural variation in this behavior (for instance, diet, processing techniques), because one major adaptive strategy is phenotypic plasticity, which in the case of behavior can be called flexibility. This flexibility is culturally supported in various primates (Whiten 2012; van Schaik 2013). In the case of food selection and diet, for instance, we see major cultural variation in food processing techniques, including technologically supported techniques (Sanz et al. 2013) and geographic variation in diet (Bastian et al. 2010).