The diversity advantage: An explanatory framework for personality traits

Why do human beings exhibit enduring personality differences, and to what extent are these differences shaped by biological and cultural evolution? Despite ongoing efforts, a consensus framework remains elusive. This paper introduces the Diversity Advantage Theory, partially shifting the focus from how personality impacts individuals to its influence within groups. Through an evolutionary lens, connections among personality, collective cognition, and group dynamics are explored, revealing that diversity in personality traits would tend to enhance collective intelligence and foster deliberation, mitigating group biases. The framework proposes that biologically evolved psychological mechanisms underlying personality, including individual niche-finding, adapt and conform to culturally evolving heuristic personality traits. This co-evolution stabilized the Big Few personality traits in western, educated, industrialized, rich, and democratic (WEIRD) societies, addressing recurring group challenges related to engagement, closure, task, risk, and change. The Diversity Advantage Theory offers a novel explanatory framework for stable personality traits, aligning with biology and testable in contemporary group contexts. At least three novel perspectives are introduced: (1) personality trait dimensions have emerged, in part, to establish normative behavior for functional group processes; (2) normative diversity along trait dimensions enhances collective intelligence; and (3) such diversity should also promote deliberation, mitigate group biases, and improve group decision-making.