ABSTRACT
In order to understand human behavior, it is essential to understand the critical role that groups play in people’s lives. Most of us belong to a range of formal and informal groups, including families, work teams, friendship cliques, social clubs, and so on. Not only do we spend a great deal of time in these groups, but they also connect us to larger social aggregates (e.g., political parties, business organizations, religious denominations) that influence our lives in important ways. Groups vary on several dimensions, including size, composition, goals, norms, status systems, and degree of member interaction and interdependence. These factors, in turn, affect both the amount and type of influence that groups exert on their members. In some cases, this influence is easy to observe, as when members of a basketball team execute a coordinated series of plays designed to score a goal. In other cases, influence is more difficult to observe, as when a teenager talking to his parents uses a slang expression that is popular among his friends. In both cases, though, group influence is at work.
