title: Institutions, parasites and the persistence of in-group preferences.
abstract: Much research has established reliable cross-population differences in motivations to invest in one's in-group. We compare two current historical-evolutionary hypotheses for this variation based on (1) effective large-scale institutions and (2) pathogen threats by analyzing cross-national differences (N = 122) in in-group preferences measured in three ways. We find that the effectiveness of government institutions correlates with favoring in-group members, even when controlling for pathogen stress and world region, assessing reverse causality, and providing a check on endogeneity with an instrumental variable analysis. Conversely, pathogen stress shows inconsistent associations with in-group favoritism when controlling for government effectiveness. Moreover, pathogen stress shows little to no association with in-group favoritism within major world regions whereas government effectiveness does. These results suggest that variation in in-group preferences across contemporary nation-states is more consistent with a generalized response to institutions that meet basic needs rather than an evolved response dedicated to pathogens.
authors.affiliation: School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, United States of America. dhruschk@asu.edu
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Hruschka
authors.forename: Joseph
authors.initials: J
authors.lastname: Henrich
mesh_terms: D000047:Academies and Institutes; D000818:Animals; D002755:Choice Behavior / Q000502:physiology*; D006076:Government; D006801:Humans; D010271:Parasites / Q000502:physiology*; D012044:Regression Analysis; D012067:Religion