In Chapter 1, the internal influences of the Tubbs Model of Small Group Interaction were introduced briefly. Chapter 4 includes a more in-depth treatment of three of these: physical environment, group size and structure, and group type. Physical environment is the setting in which small group interaction takes place. Territoriality and seating patterns are two aspects of the physical environment. Group size and structure are influences in that people in a group relate to each other in a number of patterns or communication networks. The third internal influence is the type of group. It is obvious that groups interact differently depending on what type of group they are. Some examples discussed in this chapter are primary groups, casual and social groups, work groups, educational groups, problem-solving groups, and computer-assisted groups.