The Importance of Group Size

Being the first person to arrive at a party affords the opportunity to observe a fascinating process in group dynamics. When fewer than about six people interact in one setting, a single conversation is usually maintained by everyone. But with the addition of more people, the discussion typically divides into two or more conversations. This example is a simple way of showing that size has important effects on the operation of social groups.

The basis for this dynamic lies in the mathematical connection between the number of people in a social group and the number of relationships among them as shown in Figure 3. Two people are joined in a single relationship; adding a third person results in three relationships, a fourth person yields six. As additional people are added one at a time - according to what mathematicians call an arithmetic increase the number of relationships increasesvery rapidly - in what is called a geometric increase. By the time six people have joined one conversation, there are fifteen different relationships among them, which explains why the conversation usually divides by this point.