Why Northerners and Southerners Differ in Conflict Culture

Ingroup favoritism, outgroup rejection, political oppression, legal discrimination, and bullying the media are all less prevalent among Northerners than among Southerners in the northern hemisphere, but more prevalent among Northerners than among Southerners in the southern hemisphere. Why these oppositely sloping latitudinal gradients of conflict culture above and below the equator? What on Earth is going on? The interplay of thermal stress and subsistence stress is thought to offer a better explanation than hydraulic stress and parasite stress do.