NOTE ON THE DRAWING POWER OF CROWDS OF DIFFERENT SIZE1

This study reports on the relationship between the size of a stimulus crowd, standing on a busy city street looking up at a building, and the response of passersby. As the size of the stimulus crowd was increased a greater propor-tion of passersby adopted the behavior of the crowd. The results of this study suggest a modification of the Coleman and James model of the size of free-forming groups to include a contagion assumption. Ill a typical urban setting, when a group of people engage in an action simultaneously, they have the capacity to draw others into the crowd. The actions of the initial group may serve as a stimulus for others to imitate this action. A careful analysis of the details of crowd formation is of obvious interest to a society in which collective action plays an increasingly important part in social life. One theoretical formulation that bears on this problem is that of Coleman and James (1961). Coleman and James assumed that there is a "natural process " by which free-forming groups acquire and lose members and thus reach specific maximum sizes. They have de-veloped a model that generates a size distri-bution that closely approximates the actually observed size distribution of many thousands of groups. The central assumption of their model of acquisition and loss are "a constant tendency of a group member to break away, independent of the group, thus producing a his study arose out of a graduate seminar in social psychology conducted by the first author a