How we think about others can depend upon what group they belong to. Group membership, however, is often difficult to define or identify. I am interested in a number of issues surrounding group identity, including how people from different cultural and religious perspectives are able to identify the group membership of others, how the brain responds to people within and outside of the groups, and our capacity to change how we think about other people. For example, how does experience change the way people think and reason about the actions and thoughts of others? And how does the brain differentially classify a person as an individual or a group member? To answer these questions I use functional magnetic imaging (fMRI) techniques.