Description: Human cooperation is strongly influenced by cultural systems but it is also constrained and shaped by underlying proximate biological mechanisms, which are modulated by neuro-endocrine hormones. Understanding the interaction between biology and culture can reveal how humans come to build cultural systems that promote cooperation and other forms of prosocial behavior. Our project seeks to do this through studying how a range of human social behaviors are enabled by a relatively conserved set of hormonal pathways.


Hormones have a vital role in facilitating and reinforcing behavior, including cooperation and risk-taking. Despite the importance of hormones as a proximate mechanism shaping human behavior, there is little empirical research about how hormones influence human sociality, especially outside of urban industrial contexts. For example, are the mechanisms enabling sociality context dependent and thus vary with the type of behavior? Do the same pathways underlie both intergroup competition and cooperation? Does risk-taking or collective behavior recruit mechanisms used in other domains? The answers to these questions will shed light on the proximate mechanisms that enable human sociality across domains and provide a starting point for cross-cultural comparisons. This project involves field research among Nyangatom pastoralists in Ethiopia across a range of contexts involving both higher and lower-risk activities, including cooperative and solitary behaviors such as hunting, herding, as well as intergroup interactions. Through disentangling cooperative from social and non-social behaviors and risky behaviors, our framework is designed to test key hypotheses about how hormones interact with social contexts to produce human social behavior.


Field site: Nyangatom