Infectious Diseases and Ethnocentrism

Key Insight

Infectious diseases profoundly influence political psychology and the prevalence of ethnocentrism. Historically, leaders like Hitler and figures in white hate groups have demonized out-groups by comparing them to pathogens, exemplified by the KKK's 'Praise God for AIDS!' rhetoric. Similarly, some black ethnocentrists, like Louis Farrakhan and Bill Cosby, politicized the AIDS pandemic by falsely claiming it was a government-engineered bioweapon targeting specific racial groups, highlighting the deep intersection of fear, race, and politics.

Research indicates a significant link between fear of germs and conservative attitudes. Early studies showed high-scoring authoritarians feared germs, and later findings by Nicholas Kristof and others revealed conservatives report greater disgust at potential contamination sources (e.g., public restroom faucets, sipping from others' drinks) than liberals. More rigorous studies, measuring involuntary physiological responses to disgust stimuli, correlated these reactions with 'cultural' conservatism, particularly concerning sex and reproduction, but not economic conservatism, suggesting a connection between pathogen avoidance and tribalistic attitudes.

This link extends to xenophobia: individuals who perceive higher vulnerability to infectious diseases tend to be more ethnocentric and report increased hand-washing after physical contact. A global study across 97 regions found a strong correlation (0.70) between historical pathogen prevalence and collectivism (ethnocentrism), even after controlling for population density. This suggests xenophobic attitudes evolved as a protective mechanism against pathogens by reducing exposure to out-groups. Furthermore, higher pathogen prevalence is also linked to greater sexual restraint in women, reinforcing the idea that infectious disease pressures shape social and sexual behaviors in ways that promote in-group cohesion and caution towards outsiders.