Hot and cold climates have posed differential threats to human survival throughout history. Cold temperatures can pose direct threats to survival in themselves, whereas hot temperatures may pose threats indirectly through higher prevalence of infectious disease. These differential threats yield convergent predictions for the relationship between more demanding climates and freedom of expression, but divergent predictions for freedom from discrimination.

At least four conceptually distinct mechanisms may mediate relations between parasite-stress and cultural outcomes: genetic evolution, developmental plasticity, neurocognitive flexibility, and cultural transmission. These mechanisms may operate independently or in conjunction with one another. Rigorous research on specific mediating mechanisms is required to more completely articulate implications of parasite stress on human psychology and human culture.