Parasite stress and pathogen avoidance relate to distinct dimensions of political ideology across 30 nations

People who are more avoidant of pathogens are more politically conservative, as are nations with greater parasite stress. In the current research, we test two prominent hypotheses that have been proposed as explanations for the relationship between pathogens and politics. The first, which is an intragroup, traditional norms account, holds that these relationships are based on motivations to adhere to local norms, which are sometimes shaped by cultural evolution to have pathogen neutralizing properties. The second, which is an intergroup, outgroup-avoidance account, holds that relationships between pathogen avoidance and ideology are based on motivations to avoid contact with outgroups (who might pose greater infectious disease threats than ingroup members). Results from a study surveying 11,501 participants across 30 nations are more consistent with the traditional norms account than with the outgroup-avoidance account. National parasite stress relates to traditionalism (an aspect of conservatism especially related to adherence to group norms) but not to social dominance orientation (an aspect of conservatism especially related to endorsements of intergroup barriers and negativity toward ethnic and racial outgroups). Further, individual differences in pathogen-avoidance motives (i.e., disgust sensitivity) relate more strongly to traditionalism than to social dominance orientation within the 30 nations.