ABSTRACT
An old idea in the social sciences, one that in particular can be found in the very beginnings of experimental psychology, is the belief that behavior is regular and predictable (see, for example, a brief overview in Gulliksen, 1959, pp. 178— 179). The causes and organization of any realistic facet of behavior are no doubt highly complex, yet humans do behave in predictable, sometimes even lawful, ways. Recurrent themes occur. Regularity characterizes individual as well as group activities. It would be a very unusual typology of behavior that had very many categories with only one member.
