Infectious diseases have been agents of morbidity and mortality throughout human history (Anderson & May 1991; Ewald 1994; Dobson & Carper 1996; Wolfe et al. 2007), and a growing body of empirical research indicates that people possess psychological mechanisms that serve the function of antipathogen defence. For instance, ethnocentrism, xenophobia and other specific forms of interpersonal prejudice appear to result, in part, from the operation of these mechanisms (e.g. Faulkner et al. 2004; Navarrete & Fessler 2006; Park et al. 2007).Proc. R. Soc. B doi: 10.1098/rspb.2008.0094
Pathogen prevalence predicts human cross-cultural variability in individualism/collectivism
Corey L. Fincher, Randy Thornhill, Damian R. Murray, Mark Schaller
Pathogenic diseases impose selection pressures on the social behaviour of host populations. In humans (Homo sapiens), many psychological phenomena appear to serve an antipathogen defence function. One broad implication is the existence of cross-cultural differences in human cognition and behaviour contingent upon the relative presence of pathogens in the local ecology. We focus specifically on one fundamental cultural variable: differences in individualistic versus collectivist values. We suggest that specific behavioural manifestations of collectivism (e.g. ethnocentrism, conformity) can inhibit the transmission of pathogens; and so we hypothesize that collectivism (compared with individualism) will more often characterize cultures in regions that have historically had higher prevalence of pathogens. Drawing on epidemiological data and the findings of worldwide cross-national surveys of individualism/collectivism, our results support this hypothesis: the regional prevalence of pathogens has a strong positive correlation with cultural indicators of collectivism and a strong negative correlation with individualism. The correlations remain significant even when controlling for potential confounding variables. These results help to explain the origin of a paradigmatic cross-cultural difference, and reveal previously undocumented consequences of pathogenic diseases on the variable nature of human societies.