Research shows that people usually act to maintain their image of themselves in social identities that they occupy- identities like father or son, boss or employee, friend or adversary. Current theories of identity assume that people only see themselves in one identity in each social situation, and that their behavior is guided by attempts to support that identity. Recently, the PIs have begun to consider more complex situations where people see themselves in two or more identities at the same time. For example, a policeman who stops a speeder who turns out to be his uncle is in a situation where he is simultaneously a law enforcement officer and a nephew. In this research the investigators will extend their research to examine what kinds of social systems make people more or less likely to have many identities. They will develop a theory to answer this question using computer simulations and principles about how groups and networks are related in social systems. They also investigate what kinds of situations lead people to enact more than one identity at a time, and how these situations affect how they feel. A data set that samples the situations in which University of Arizona students, faculty and staff found themselves will be used to test predictions that multiple-identity occupancy causes stress and the experience of mixed emotions.