I use a combination of mathematical modeling and experimental work, mainly with fish, to study the evolution of social behavior. Many behaviors, like cooperation or mating displays, only make sense if we consider the social context in which they occur. However, that social context emerges from social interactions that are also under selection. Therefore, social behavior is both a target and an agent of selection.

One of the key questions that I am working on is why organisms invest in cooperative behavior, that is, behavior that provides benefits to others. I focus on so-called cooperatively breeding systems, in which some group members help raise the offspring of others in the group. In some cases, these individuals apparently cooperate not only by helping, but also by restraining their own reproduction or growth. Understanding cooperative breeding involves understanding why animals group, why they help and the interactions among group members. I use evolutionary dynamics approaches to model the dynamics and stability of cooperative behavior in these systems. As well, I use cooperatively-breeding cichlid fish from Lake Tanganyika in East Africa as an experimental system. In addition to this work on cooperation, I also work on social influences on mating systems, foraging and territorial behavior.