Publications and Outreach

Friendship: Development, Ecology and Evolution of a Relationship
University of California Press. 2010.

FriendshipBookCover.jpg Friends are generous and cooperative with each other in ways that appear to defy standard evolutionary expectations, frequently sacrificing for one another without concern for past behaviours or future consequences. In this book, I tackle this apparent puzzle. Synthesizing an array of cross – cultural, experimental, and ethnographic data, I try to understand the broad meaning of friendship, how it develops, how it interfaces with kinship and romantic relationships, and how it differs from place to place. I argue that friendship is a special form of reciprocal altruism based not on tit – for – tat accounting or forward – looking rationality, but rather on mutual goodwill and knee – jerk altruism that is built up along the way in human relationships.


Choosing the Good

ChoosingtheGoodBrainbow.jpg Choosing the Good, at the ASU Museum of Anthropology, explores how people in different cultures make tough choices between the better of two goods.
The museum exhibit presents our research on how people make tough choices between loyalty and fairness in 8 field sites around the world. It is sponsored by the New Science of Virtues project at University of Chicago and the School of Human Evolution and Social Change.


Searching for the Origins of Collectivism and Individualism

An essay in This View of Life



Dataset used in Hackman and Hruschka 2013


Select Publications


Biocultural and social factors in health

Cultural and social factors in cooperative behavior

Arizona State University

School of Human Evolution and Social Change
Tempe, AZ 85287-2402
Tel (480) 965-3087