Human social motives evolved to keep groups bounded and optimally sized

Evidence

Based on this analysis of one structural requirement for group survival, I hypothesized that the conflicting benefits and costs associated with expanding group size would have shaped social motivational systems at the individual level. A unidirectional drive for inclusion would not have been adaptive without a counteracting drive for differentiation and exclusion. Opposing motives hold each other in check, with the result that human beings are not comfortable either in isolation or in huge collectives. These social motives at the individual level create a propensity for adhering to social groups that are both bounded and distinctive. As a consequence, groups that are optimal in size are those that will elicit the greatest levels of member loyalty, conformity, and cooperation, and the fit between individual psychology and group structure is ensured. — Roderick M. Kramer, Geoffrey J. Leonardelli, Robert W. Livingston, Social Cognition, Social Identity, and…, 2507

Categorization

• DEFINE: This is the core statement of optimal distinctiveness theory - the tension between inclusion and differentiation drives humans toward mid-sized bounded groups.