YERKES, ROBERT MEARNS

(b. Breadysvile, Pennsylvanis, 26 May 1876; d. New Haven, Connecticut, 3 February 1956)

Comparative psychology.

Yerkes was the oldest child of Silas Marshall Yerkers and Susanna Addis Carrell Yerkesw, members of well-established farm families residing north of Philadelphia. As a boy he lived close to nature, and his familiarity with domestic and wild animals eventually contributed to his vocational choice. He attended and ungraded rural school and at the age of fifteen entered the State Normal School at West Chester, transferring, in 1892 to Ursinus College, first as a preparatory and then as a collegiate student (A.B., 1897). In 1897 Yerkes entered Harvard, where he was awarded an A.B.after one year and proceeded into graduate work without pause, working with Hugo Munsterberg. He recerived the A.M.in 1899 and the Ph,D. in psychology, in 1902. By the latter year he had already launched his scientific career with publications and was appointed instructor in psychology at Harvard.

Yerkes was one of the first of a new breed of comparative psychologists who worked with their animal subjects in a laboratory setting. He was preceded by only a few years by E.L.Thorndike (whom he assisted one summer at Woods Hole) and was a collaborator (mostly by mail) with a slightly younger man, John B.Watson, Thorndike’s work led him into learing theroy and educational psycholoy. Wastson’s researches led him into methodological reformism and antimentalism in general psycholoy. Yerkes, in contrast with these eminent peers, recognized the kinship of tha animal psyche to that of man; but whatever his speculations on that kinship, in his research he studied animal behavior for its own sake, assuming that he was dealing with animal mentality as such. Relatively early in his career he was convinced that observing the animals with mental processes most like those of man, the apes, would be of great importance to psycholoy. He envisaged the founding of an institute in which these animals might be studied, but decades passed before he realized this project.

Yerkes became the most versatile psychologist of his generation, responding in large part to the stimulation of the Harvard enviroment in the years that he spent there as a faculty member until 1917. Under the aegis of Harvard psychiatrist E. E.Southard, Yerkes spent half his time from 1913 to 1917 as psychologist to the Boston Psychopatic Hospital. Although he published realtively little based on that experience, he bacame deeply involved in mental testing as it was then practiced. As a result, from 1917 to 1919 Yerkes was in effect largely in charge of the psychological testing of U.S.Army personnel in World War I. The large-scale use of psychological devices at that time substantially established the profession of psychology in a way quite different from its tendency toward academic islotion before the war Yerkes, through his promotional and organizing abilities, was one of the key figures, responsible for the conception and execution of the program.

Although appointed chairman of the psychology department at the University of Minnesota in 1917, Yerkes never took up residence in Minneapolis. From 1919 to 1924 he stayed in Washington with the National Research Council and continued to exploit his ability to facilitate the work of others. He headed N.R.C. programs to explore the characteristics of various types of humans who migrate (with immigration-exclusion legislation in mind) and to encourage and support scientific investigation of sexuality. He also was elected president of the American Psychological Association for 1916-1917, while still an assistant professor at Harvard. Yerkes thus spent the period of the war and afterward in the heart of the American scientific establishment, helping to make policy and channel funds. Although he did not feel himself to be one of the scientist-politicians, he served on committess adn advisory groups and exerted great influence on the institution and programs of American science in the 1920’s and 1930’s.

Not until 1924 did Yerkes return to his career as comparative psychologist, when Yale offered him an opportunity to join its new Institute of Psychology and devote himself primarily to advanced work with nonhuman primates. By 1929 he had founded an experimental station near Orange Park, Florida, later named the Yerkes Laboratories of Primate Biology, which was the nucleus of the present Yerkes Regional Primate Research Center. As preparation for this work he and his wife, Ada Watterson, Yerkes, published a monumental book, The Great Apes; A Study of Anthropoid Life (1929), which for decades remained the standard work on the biology adn psychology of these mammals.

Yerkes had originally wanted to become a phsician, but he was turned away from medicine by his interest in laboratory research. Nevertheless, throughout his life his basic approach to comparative psycholoy remained close to biology. Indeed, at Yale his appointment ultimately was in the department of physiology. In psychology, Yerkes’ formal stance was very traditional—influenced, he said, by the structuralism of E. B.Titchener of Cornell, Yerkes’ early research work, dealing with invertebrates, involved testing organic reactions to sensory input. He soon began working with vertebrates, giving attention not only to sensations but also to instinct, imitation, and learning. His classic study of the behavior of the dancing mouse (1907) did much to establish the rat and mouse as standard laboratory animals in psychology. Many of his most important publications in science involved new techniques for psychological investigation. With his wide-ranging interests, Yerkes also was responsible for contributions as diverse as (with S.Morgulis) publishing the first important American notice on Pavlov’s work (1909) and a discussion of the application of psychological findings, to illumination engineering (1911). In 1915 Yerkes spent half a year with G.V.Hamilton’s primate colony in Sanata Barbara, California; and after that period except for the war and N.R.C. service, devoted himself largely to the monkeys and apes. The staff at the Orange Park laboratories employed both experimental and observational methods, mostly utilizing chimpanzees fro subjects and produced a prodigious number of publications. The topics covered involved not only thinking processes and adaptation but also physiology and evn medicine.

Yerkes was a determined persistent leader. A large part of his contribution to science consisted of organizing or directing it. He was, for example, a prime mover in the reform of the structure of the American Psychological Association in 1943. He was founding editor of the Journal of Animal Behavior in 1911 and held other important editorial positions. Yerkes felt that he had a limited amount positions. Yerkes felt that he had a limited amount of energy that was always overtaxed, so what resources he had were used efficiently. He retired as director of the Orange Park laboratories in 1941 and in 1944 retired from Yale. He continued to publish, although at a diminishing rate, and was still active in organizing psychology in the World War II defense effort

BIBLIOGRAPHY

I. Original Works. The number of Yerkes’ published works is very large. The most complete bibliography is in Ernest R. Hilgard, “Robert Mearns Yerkes, May 26, 1876-February 3, 1956,” in Biographical Memoirs National Academy of Sciences38 (1965) 421–425, Probably no bibliography will ever be complete, including all of the editorial material and book reviews contributed to various journals, especially those he edited. Yerkes published a short autobiography, “Robert Mearns Yerkes, Psychobiologist,” in Carl Murchison, ed., A History of Psychology in Autobiography11 (Worcester, Mass., 1932), 381–407; and, post-humously, some reminiscences, “Creating a Chimpan-zee Community,” Roberta W. Yerkes, ped., in Yale Journal of Biology and Medicine36 (1963), 205–223.

The Yerkes Papers, in the Yale University Medical School Library, constitute one of the chief sources of the history of American psychology in the first half of the twentieth century. They include an unpublished autobiography, a bibliography, and a large number of letters and personal papers covering not only Yerkes and his career but also all of the activities in which he was interested

II. Sendary Litter. The most authoritative account of Yerkes’ life is Hilgard’s (see above), 385–425. Also see E. G. Boring “Robert Mearns Yerkes (1876-1956),” in Yearbook. American Philosophical Society (1956), 133–140; Leonard Carmichael, “Robert Mearns Yerkes, 1876-1956,” in Psychological Review64 (1957), 1–7; and Richard M. Elliott, “Robert Mearns Yerkes (1876-1956),” in American Journal of Psychology69 (1956), 487–494.

John C. Burnham

Robert Mearns Yerkes

Robert Mearns Yerkes (1876-1956), American psychologist, played a leading role in the development of psychology in America by laying the groundwork for important new areas of both research and practice.

Robert Yerkes was born in Bucks County, Pa., on May 26, 1876. He graduated from Ursinus College in 1892. Financial problems and the offer of a fellowship in zoology at Harvard deflected him from a long-held wish to study medicine. At Harvard he shifted gradually from zoology to animal psychology and received his doctorate in 1902. He remained at Harvard to teach and do research for the next 15 years. In 1916 he was elected president of the American Psychological Association.

As chief of the Psychology Division in the Surgeon General's Office during World War I, Yerkes organized the first large-scale utilization of psychologists in a professional capacity. He developed the Army Alpha Testing Program. This mental screening device, used on 1.7 million recruits, established the value of applying psychological methods to solving human problems and was a major factor in the development of psychology as an independent profession in America. Yerkes's books that resulted from this work, Army Mental Tests (1920) and Psychological Examining in the U.S. Army (1921), were models for the further expansion of intelligence testing as a field in psychology and are still in use today.

Yerkes also devised basic methodological tools for studying learning in animals and enunciated an important law relating the effect of fear on learning. Even more important was his pioneering effort to promote research on primates and the scientific study of sex. From 1921 until 1947 Yerkes served as chairman of the National Research Council Committee for Research on Problems of Sex, which sponsored projects that led to such studies as the Kinsey Report.

Yerkes's classic studies The Great Apes: A Study of Anthropoid Life (1919), coauthored with his wife, and Chimpanzees: A Laboratory Colony (1943) established the significance of studying the almost-human primate behavior. While a professor of psychology at Yale from 1924 to 1944, Yerkes established the first experimental primate breeding colony in America at Orange Park, Fla. It was renamed the Yerkes Laboratory of Comparative Psychobiology after his death.

Although sidetracked from pursuing a medical career directly, Yerkes realized his concern with medicine in his efforts toward making psychology one of the helping professions. He viewed his scientific studies of behavior as part of a basic science fundamental to the care of human problems. He died on Feb. 3, 1956.

Further Reading

Yerkes's autobiography appears in A History of Psychology in Autobiography, edited by Carl Murchison (1961). The most extensive review of Yerkes is Earnest R. Hilgard's "Robert Mearns Yerkes" in National Academy of Sciences Biographical Memoirs, vol. 38 (1965), which includes a complete bibliography of Yerkes's writings. See also E. G. Boring's "Robert Mearns Yerkes (1876-1956)" in the 1936 Yearbook of the American Philosophical Society, published in 1956. □

Robert Mearns Yerkes

1876-1956

American psychologist who is regarded as one of the founders of comparative animal psychology. Yerkes was interested in the great apes as well as psychological testing and the measurement of human mental ability. During World War I, Yerkes directed the first mass-scale testing program, which administered psychological tests to almost two million men. The Yale Laboratories of Primate Biology (later, the Yerkes Laboratories of Primate Biology) became a major center for the study of primate behavior.