Hull, Clark
Hull, Clark 1884-1952
A leading American psychologist during the middle decades of the twentieth century, Clark Leonard Hull established an early reputation for carefully controlled research and formulated an influential version of neobe-haviorist learning theory. His ambitious theoretical system was marked by quantitative precision and systematic exposition in terms of postulates and equations.
Hull was raised on a small farm in Michigan and attended Alma College in preparation for a career in engineering. But while convalescing from polio, he read William James’s Principles of Psychology (1890) and transferred to the University of Michigan to study psychology. He then entered graduate school at the University of Wisconsin, receiving a doctorate in 1918 with a thesis on concept formation under the direction of Joseph Jastrow (1863–1944).
Remaining at Wisconsin as an instructor, Hull pursued research in three areas. His study “The Influence of Tobacco Smoking on Mental and Motor Efficiency” (1924) produced mixed results but was noteworthy for implementing a placebo design in which blindfolded subjects smoked pipes that delivered either tobacco or heated, smoke-scented air. He also conducted quantitative studies of aptitude testing and carefully controlled research on hypnosis, eventually publishing well-received books on both topics. His Hypnosis and Suggestibility (1933) was a pioneering work in the scientific study of hypnotic phenomena.
In 1929 Hull received an appointment at Yale, where his interests shifted to behaviorist learning theory. Inspired by the works of the Russian physiologist Ivan Pavlov (1849–1936) and the American psychologist Edward Thorndike (1874–1949), he published a series of “miniature systems”—theoretical models of limited scope that applied to circumscribed domains of learned behavior. The systems made ingenious use of the explanatory constructs—such as pure stimulus acts and habit-family hierarchies—that would become standard devices for “Hullians” in the following decades. During the 1930s, Hull also designed and built robotic machines that could exhibit learned behavior, a practice that prefigured later uses of computers to model mental processes.
Meanwhile, Hull assumed a leadership role at Yale’s Institute of Human Relations, which attracted talented young psychologists otherwise unemployed during the Great Depression. Hull’s weekly seminars at the institute were devoted to applications of behavioral principles to phenomena of social learning, aggression, and psychopathology. His students and associates at Yale included such notables as Neal Miller, John Dollard, Eleanor Gibson, Charles Osgood, Robert Sears, and Kenneth Spence. As Hull’s chief disciple, Spence trained scores of students in the Hullian tradition at the University of Iowa.
Elected president of the American Psychological Association in 1936, Hull furthered his standing with the 1943 publication of his masterwork Principles of Behavior. Consistent with the logical positivist philosophy of the time, the book adopted a hypothetico-deductive method in which theory was framed as postulates and theorems to be subjected to experimental verification. It quickly became the most cited work in experimental psychology and led to Hull’s involvement in celebrated learning-theory debates, notably with Edward Tolman (1886–1959) and Kurt Lewin (1890–1947), during the 1940s.
In Essentials of Behavior (1951), Hull revised the postulates of the Principles in light of anomalous findings, but his system became mired in the complexities of learned behavior. By the late 1960s, his influence had crested and many psychologists were turning to the simplified neobe-haviorism of B. F. Skinner (1904–1990) or to cognitive approaches. Hull’s efforts at grand theory are now largely regarded as failures, but his legacy of careful experimentation and domain-limited theoretical models remains influential.
BIBLIOGRAPHY
Amsel, Abram, and Michael E. Rashotte, eds. 1984. Mechanisms of Adaptive Behavior: Clark L. Hull’s Theoretical Papers, with Commentary. New York: Columbia University Press.
Hilgard, Ernest R., and Gordon H. Bower. 1966. Theories of Learning. 3rd ed. New York: Appleton-Century-Crofts.
Hull, Clark L. 1952. Autobiography. In A History of Psychology in Autobiography, vol. 4, eds. Edwin G. Boring, Heinz Werner, Herbert S. Langfeld, and Robert M. Yerkes, 143–162. Worcester, MA: Clark University Press.
Laurence D. Smith