Your family sitting down to dinner. A group of coworkers having a drink together at the end of a shift. Six exasperated parents sitting in a doctor’s office with sick kids. Each of these examples involves multiple people engaged in some activity—and most of us would probably say that these are examples of “groups of people.” But are they really groups? We’ll explore what it actually means to be in a group, in addition to understanding what types of groups exist and how those groups develop in the first place.