Cumulative Record. Chapter 7: Are Theories of Learning Necessary. Quote 14

[Many events do not occur] often enough to make a rate of response meaningful. But these activities are not responses. They are not simple unitary events lending themselves to prediction as such. If we are to predict marriage, success, accidents, and so on, in anything more than statistical terms, we must deal with the smaller units of behavior which lead to and compose these unitary episodes. (p. 77)