HARLOW, HARRY (1905-1981)

Harry F. Harlow was born in Fairview, Iowa, on October 31, 1905, and died on December 6, 1981. He attended Reed College in 1923 before transferring to Stanford, where he received his Ph.D. in 1930 under the supervision of C. P. Stone. Harlow's first appointment was at the University of Wisconsin, where he later established the Wisconsin Primate Laboratory. Except for the period from1949 to 195l, when he was chief psychologist for the U.S. Army, he remained at Wisconsin until his formal retirement in 1974, when he moved to the University of Arizona. Harlow's research, characterized by imaginative methods of studying cognition and motivation, led to important discoveries. He was elected president of the American Psychological Association and received its Distinguished Scientific Contribution Award. He also received awards from the Society for Research in Child Development and was recipient of the Kittay International Scientific Foundation Award, the Gold Medal Award of the American Psychological Foundation, and the U.S. National Medal of Science.

Harlow was primarily interested in the cortical localization of intellectual functions such as learning and memory, and decided to work with primates because of their obvious cognitive capacities. As he approached this problem, he was convinced that the contemporary learning systems were fundamentally limited because they were based upon inadequate information, and he set out to collect such information from his monkeys in a systematic manner. One of the most important innovations that Harlow introduced was the study of transfer of training. Although there was a long history in the study of this general issue, previous workers had studied interproblem learning over a narrow range of problems in which subjects were trained to mastery on a given problem before being shifted to new ones. Harlow departed radically from this approach by training animals on individual problems for a small number of trials before shifting to new problems. He showed that on the initial training trials animals worked largely by trial and error, but at some point they began to catch on to a general principle that could be used to successfully solve problems in a single trial; that is, the animals had learned how to learn, a process that he called the development of a "learning set." This simple observation was important for theoretical reasons, but it had another important impact: It could be used to study the organization of cortical processes related to learning and memory. This represented another major breakthrough, and this type of behavioral analysis still represents a major tool in studies of neural mechanisms underlying learning and memory processes.

Harlow was convinced that many of the shortcomings of the contemporary theoretical systems were due to the paucity of data on the ontogenetic development of learning, perception, and motivation. In an effort to determine how and when different learning and perceptual processes developed, he and his colleagues began a major program in which infant monkeys were separated from their mothers at birth and then studied intensively over the ensuing years. While the contributions of these experiments go far beyond the questions of learning and memory, it was clear from these studies that there were major maturational changes in the performance of monkeys on different learning tests. These changes could not be accounted for by traditional learning theories and thus led to a new field of inquiry in learning and memory research.

Finally, Harlow was a major advocate of the use of the comparative method in studies of learning and memory: "Basically the problems of generalization of behavioral data between species are simple—one cannot generalize, but one must. If the competent do not wish to generalize, the incompetent will fill the field" (Harlow, Gluck, and Suomi, 1972). The comparative studies of Harlow and those that followed were based upon the concepts related to learning sets, which led in turn to major advances in the understanding of the phylogenetic changes in learning and memory abilities.

Harlow thus made a unique and long-lasting contribution not only to the way in which learning and memory are now studied but also to the development of psychological theory of learning and memory. His work helped shape the nature of the questions that are now being addressed.

See also:COMPARATIVE COGNITION

Bibliography

Harlow, H. F. (1956). Learning set and error factor theory. In S. Koch, ed., Psychology: A study of a science, Vol. 2, pp. 492-537. New York: McGraw-Hill.

Harlow, H. F., Gluck, J. P., and Suomi, S. J. (1972). Generalization of behavioral data between nonhuman and human animals. American Psychologist 27, 709-716.

Sears, R. R. (1982). Harry Frederick Harlow (1905-1981). American Psychologist 37, 1,280-1,281.

Bryan E.Kolb