With my interdisciplinary training in social and natural sciences at the University of California, Davis, I am interested in human social organization, and how a variety of forces influence patterns of cooperation and conflict. Most of my work has a foundation in cultural evolutionary theory developed by Peter Richerson.  

Experimental Economic Games and Social Institutions 

At the micro-level, I have used games developed by experimental economists to evaluate how much cultural rules influence the magnitude and scope of prosocial behavior. Some of this work was conducted in collaboration with Craig Hadley. The goal of this work has been to identify the relative importance of group-level variables (e.g., social institutions) and individual-level variables (e.g., religious participation, personality dimensions) on prosocial outcomes such as sharing, trust, and cooperation. These games are important in organizational research, as they provide an innovative tool to evaluate the mechanisms that lead to either efficient or inefficient outcomes. 

Cooperation and Conflict: Sungusungu Vigilantes of Tanzania 

Organizations must resolve collective action problems, or the ability to prevent “free-riders” from enjoying organizational services without paying the costs. In both my theoretical and empirical work, I stress the importance of social institutions (normative patterns of behavior defined by sets of rules that are enforced with sanctions) to provide the foundation for organizational cooperation. To evaluate institutional mechanisms that promote collective action, I studied how the Sukuma ethnic group in Tanzania, East Africa has successfully limited crime within their communities by creating and sustaining large-scale and cooperative “vigilante” organizations.  

Social Organization and Violence

Some types of organizations use violence (rather than other non-violent strategies) as a way to resolve conflict and promote their organization’s goals. For example, Chinese male associations called “tongs” in American Chinatowns protected their dealings in illegal vice markets by upholding their group “honor” with deadly violence. I am currently working with Kevin Mullen to investigate patterns of homicide in San Francisco from 1850 to 2000. I have also explored how community and family organizations historically led to high rates of interpersonal violence in the American South. Because these organizations have a cultural foundation, and culture change is sometimes slow, high rates of violence in the modern South may continue to be influenced by “cultures of honor”.