This article employs cross-national and cross-cultural methods to investigate whether pathogen stress is a direct determinant of authoritarianism. The study controls on other factors such as famine, warfare, and malnutrition and evaluates alternative causal models.

In order to evaluate an adaptive justification for restriction of ritualized physical contact, the authors test association between three manifestations of physical interaction and prevalence of pathogens cross-culturally. Their expectation, supported by two of the three tested hypotheses, is that higher pathogen prevalence will lead to customs of restricted physical contact. Both cultural and biological evolution are suggested to be influential in selecting for physically intimate behaviors.

The authors contribute to a growing body of theory which posits cultural differences as a result of variable pathogen prevalence by testing the relationship between pathogen richness and various measures of conformity in a cross-regional sample. After controlling for confounds such as life expectancy, GDP, population density, arable land area, and agricultural labor force, the authors suggest that conformity is emphasized to varying degrees in response to the increased vulnerability to pathogens generally associated with deviation from normative social conduct.

The authors test the relationship between disease prevalence and three different personality traits, with the expectation that pathogen load will be negatively associated with degree of sociosexuality, extraversion, and openness to experience. This prediction is supported by all three tests, which they theorize is an example of cultural behaviors adapting to reduce vulnerability to environmental risks.