Humans sometimes make economic decisions that go against their own self interests. Why, for example, do people gamble when everyone knows they are going to lose money? In my research, I look for the evolutionary origins of these decision-making biases. It may be that these patterns of behavior were useful in our evolutionary past. In order to explore these types of issues, I research decision-making in nonhuman primates. I am particularly interested in how decision-making processes are influenced by the social dynamics within groups.