Control: A History of Behavioral Psychology

4. The Behaviorist as Research Manager: Clark L. Hull and the Writing of Principles of Behavior

4 The Behaviorist as Research Manager Clark L. Hull and the Writing of Principles of Behavior Hull’s major work, Principles of Behavior, which he and his friends always referred to as his magnum opus, was the first at­ tempt to write an all­embracing psychological theory using the prin­ ciples of behaviorism.1 Hull intended the Principles to be the first part of a trilogy, since it did no more than state a set of general principles. It was followed by the second part, Essentials of Behavior, in which he demonstrated (to his satisfaction, at least) that his principles yielded precise quantitative behavioral predictions.2 The third (un­ written) part would have dealt with applications of behaviorism to so­ cial and ethical questions. Although Hull was the first behaviorist to produce a comprehen­ sive theory, his work was by no means without precedent. Tolman, Guthrie, and Skinner all had a considerable start on him. To some ex­ tent, Hull played a role that his three possible rivals refused. Skinner’s ambitions to produce an overall theory of behavior seem to have been deferred until the publication in the early 1950s of Science and Human Behavior.3 Guthrie published comparatively little. Tolman, who had an early start, was not a proselytizer or system builder, in part because it would seem that his assessment of the difficulties in­ volved was more realistic than Hull’s. Hull always knew that Tolman was his only peer but realized early on that Tolman would never be his rival.4 Hull’s method of work has left a unique archive. As both a diarist and a correspondent he recorded his mental life prolifically. From 1935 onward, Hull maintained an exceptionally rich correspondence with his leading disciple, Kenneth W. Spence.5 The two discussed each 103 104 | The Behaviorist as Research Manager phase of the writing of the book in great detail. It is therefore possible to chart the development of Hull’s thinking very closely. Hull’s Re­ search Memoranda, the record of the topics discussed at the seminars Hull chaired at Yale’s Institute of Human Relations, also give a de­ tailed picture of the course of Hull’s thinking from 1936 to 1944.6 From 1929 to 1943 Hull published twelve theoretical articles in the Psychological Review, hoping in this way to develop his ideas, get feedback from his colleagues, and, above all, stake out a claim as the sole creator of a comprehensive behaviorist theory.7 The most signifi­ cant article in the series appeared in 1937, when Hull laid out the so­ called mini­system (the precursor of the fully worked out theory).8 Unfortunately, by the time Hull started to work in earnest on Princi­ ples of Behavior he was fifty­five, and two years after its publication he developed a serious cardiac condition. As a result, the projected third part of the trilogy (on applications of behaviorism to social is­ sues and ethics) was not written. In this chapter I analyze the development of Hull’s magnum opus from a number of perspectives—his stance as a theorist, his early work on the theory of the gradient of reinforcement, and the influence of several external and internal influences on the final form of the the­ ory of behavior as it appeared in the Principles. Throughout, I have attempted as much as possible to follow the historical development of his theory, allowing for a certain amount of deviation from strict chronology to follow individual themes. The work on the Principles can be divided into two phases. The first was a long preparatory period starting with a seminar course on behaviorism that Hull gave at Wisconsin in 1925–26 and ending in 1938. During the preparatory period Hull seems to have been envis­ aging a work of much broader scope than the Principles. In it he would have made detailed references to many aspects of human be­ havior. Toward the end of the preparatory period Hull started work on his mathematico­deductive theory of rote verbal learning and, dur­ ing most of 1939, suspended work on the Principles altogether. Given Hull’s views on the nature of theory, we can include time spent on the rote­learning monograph as a prelude to work on the Principles.9 From letters to Spence we know that the work on the manuscript it­ self began some time in the first week of October 1939 and ended at 5:20 p...