Chapter 5 Separate and Together: Life in Groups What Is a Group? A group is a collection of people who share some attribute, identify with one another, and interact with each other. A crowd is different because it is simply a temporary gathering of people in a public place, where members may interact but do not identify with each other and will not remain in contact. A crowd is one example of an aggregate, a collection of people who share a physical location but do not have lasting social relations.