My lab focuses on intergroup social cognition. Humans are perhaps the most social species on the planet. One prominent form this sociality takes is the tendency to divide individuals into social groups. Most species do this in a very limited set of ways, forming groups on just a few dimensions such as biological relatedness and sex. By contrast, humans are driven to create groups based on myriad other properties including shared beliefs (e.g. religion), shared origins (e.g. nationality), shared traits (e.g. introverts), and shared affiliations (e.g. Yankees fans). Once we are in such groups, they systematically affect how we see the world, for example by biasing our attention towards positive features of the ingroup. Indeed, this tendency is so general that we will even start to immediately prefer previously unfamiliar groups to which we have been randomly assigned. What are the origins of this pervasive psychological tendency? My lab addresses this question by studying how knowledge of social groups is acquired, both in cognitively mature adults and in the developing minds of children. Out of the universe of properties along which people differ, how do we decide which to use as the basis of social groups? Do we have natural tendencies to partition the social world in certain ways? What is the role of cultural input in shaping the intergroup mind? We employ experimental and cross-cultural methodologies to gain purchase on these questions.