When humans wage war, it is not unusual for battlefields to be strewn with dead warriors.
These warriors typically were men in their reproductive prime who, had they not died in battle, …

Humans in many societies cooperate in economic experiments at much higher levels than
would be expected if their goal was maximizing economic returns, even when their …

Cultural transmission in nonhuman animals is often sex biased, with females more frequently
or efficiently learning cultural behaviors than males. The evolutionary origins of sex-biased …

… Elsewhere (Zefferman & Mathew 2020) we showed that Turkana warriors experience high
rates of PTSD, with 28% of subjects reporting symptom severity scores that would qualify them …

Military personnel in industrialized societies often develop posttraumatic stress disorder (PTSD)
during combat. It is unclear whether combat-related PTSD is a universal evolutionary …

Global climate change, one of the most formidable sustainability problems facing humanity,
is a particularly challenging collective action problem, because it is global, requiring the …

Some human groups are organized hierarchically and some are distributed. Both types of
groups occur in economic, political, and military domains, but it is unclear why hierarchical …

Smaldino makes a solid contribution to the literature on the evolution of human social
organization by pointing out that group-leveltraits (GLTs) often emerge from the interactions of …

Why are some human groups organized hierarchically and others are distributed? Human 2
groups are often cooperative with cooperation often maintained by monitoring and the …

Methods To evaluate combat stress in a non-industrialized society, we conducted research
with Turkana pastoralist warriors in the semi-arid northwest region of Kenya. Pastoral …