Robert Yerkes

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Robert Yerkes
BornMay 26, 1876 (1876-05-26)
DiedFebruary 3, 1956(1956-02-03) (aged 79)
Known forintelligence testing
Scientific career

Robert Mearns Yerkes (/ˈjɜːrkz/; May 26, 1876 – February 3, 1956) was an American psychologist, ethologist, eugenicist and primatologist best known for his work in intelligence testing and in the field of comparative psychology.

Yerkes was a pioneer in the study both of human and primate intelligence and of the social behavior of gorillas and chimpanzees. Along with John D. Dodson, Yerkes developed the Yerkes–Dodson law relating arousal to performance.

As time went on, Yerkes began to propagate his support for eugenics in the 1910s and 1920s. His works are largely considered biased toward outmoded racialist theories by modern academics.[1][2]

He also served on the board of trustees of Science Service, now known as Society for Science & the Public, from 1921-1925.

Education and early career[edit]

Robert Yerkes was born in Breadysville, Pennsylvania (near Ivyland, Pennsylvania). Growing up on a farm in rural Pennsylvania, Robert Yerkes wanted to leave the hard life of the rural farmer and become a physician. With the financial help of an uncle, Yerkes attended Ursinus College from 1892 to 1897. Upon graduating he received an offer from Harvard University to do graduate work in Biology. Faced with a choice of Harvard or medical training in Philadelphia, he chose to go to Harvard.

At Harvard, Yerkes became interested in animal behavior, so much so that he put off further medical training to study comparative psychology. He earned his Ph.D. in the Psychology Department in 1902.

His early career was strongly influenced by the debts Yerkes incurred paying for school. Upon his graduation from Harvard, he took up a position with the school as an instructor and Assistant Professor in Comparative Psychology. He had to supplement his income during the summer for several years by teaching general psychology at Radcliffe College. Another part-time job he took on was being the director of psychological research at the Boston Psychopathic Hospital, Boston, Massachusetts.

In 1907, Yerkes published his first book, The Dancing Mouse. Among his friends during this time was future behaviorist John Watson, with whom he exchanged ideas and collaborated. He was also a member of the Wicht Club (1903–1911).

Intelligence testing and eugenics[edit]

In 1917, Yerkes served as president of the American Psychological Association (APA). Under his influence, the APA began several programs devoted to the war effort in World War I. As chairman of the Committee on the Psychological Examination of Recruits, he developed the Army's Alpha and Beta Intelligence Tests, the first nonverbal group tests, which were given to over 1 million United States soldiers during the war.

Although Yerkes claimed that the tests measured native intelligence, and not education or training, this claim is difficult to sustain in the face of the questions themselves. Question 18 of Alpha Test 8 reads: "Velvet Joe appears in advertisements of ... (tooth powder)(dry goods)(tobacco)(soap)."[3]

Yerkes used the results of tests such as these to argue that recent immigrants (especially those from Southern and Eastern Europe) scored considerably lower than older waves of immigration (from Northern Europe.) The results would later be criticized as very clearly only measuring acculturation, as the test scores correlated nearly exactly with the number of years spent living in the US. Nonetheless, the effects of Yerkes work would have a lasting effect on American xenophobia and anti-immigrant sentiment. His work was used as one of the eugenic motivations for harsh and racist immigration restrictions.[4]

He was appointed as an "Expert Eugenic Agent" to The House Committee on Immigration and Naturalization, where his work would contribute to the creation of the discriminatory National Origins Formula.[4] In his introduction to Carl C. Brigham's A Study of American Intelligence (which helped popularize eugenics in the U.S.), Yerkes stated that "no one of us as a citizen can afford to ignore the menace of race deterioration."[5]

Along with Edward L. Thorndike, Yerkes was a member and Chairman of the Committee on Inheritance of Mental Traits, part of the Eugenics Record Office, which was founded by Charles Benedict Davenport, a former teacher of Yerkes at Harvard.[6]

National Research Council[edit]

Immediately after World War I, Yerkes worked as a paid officer for the United States National Research Council (NRC) and took the helm of the NRC Committee for Research in Problems of Sex. The Committee for Research in Problems of Sex helped Yerkes establish close relationships with officers from Rockefeller philanthropic foundations. These relationships later helped him to solicit substantial funds for his chimpanzee projects.


Yerkes had a long and storied fascination with the study of chimpanzees. He had spent time observing chimpanzees in Cuba at Madame Abreu's colony in the early 1920s, and had returned from the trip determined to raise and observe chimps on his own. He began by purchasing two chimpanzees, Chim and Panzee, from a zoo. He brought the two chimps home, where they lived in a bedroom and ate with a fork at a miniature table. Chim was a particular delight for Yerkes, and the summer that chimp and psychologist spent together is memorialized in Almost Human (1924).[7]

In 1924, Yerkes was hired as a professor of psychobiology, a field he pioneered, at Yale University. He founded the Yale University Laboratories of Primate Biology in New Haven, followed by his Anthropoid Breeding and Experiment Station in Orange Park, Florida, with funds from the Rockefeller Foundation. After his death, the lab was moved to Emory University in Atlanta, Georgia, and is now called the Yerkes National Primate Research Center. The primate language Yerkish was developed there. Yerkes retired from his position as Director in 1942, where he was replaced by Karl Lashley.[8]

Asked how to say his name, he told The Literary Digest it was YER-keez.[9]


Yerkes gave his name to the National Primate Research Center in Atlanta, Georgia at Emory University.[10]


  • 1907, The Dancing Mouse, A Study in Animal Behavior
  • 1911, Introduction to Psychology
  • 1911, Methods of Studying Vision in Animals (with John B. Watson)
  • 1914, Outline of a Study of the Self
  • 1915, A Point Scale for Measuring Mental Ability (with co-authors)
  • 1916, The mental life of monkeys and apes
  • 1920, Army Mental Tests (by Clarence S. Yoakum and Robert M. Yerkes)
  • 1925, Almost Human
  • 1929, The Great Apes (with Ada W. Yerkes)
  • 1943, Chimpanzees; a laboratory colony

See also[edit]



  1. ^ "Bio Robert Yerkes" Archived 2011-03-10 at the Wayback Machine. Facing History. Retrieved February 17, 2010.
  2. ^ "History of Physical Anthropology". Google Books. Retrieved February 17, 2010.
  3. ^ Black, Edwin (2012). War Against the Weak: Eugenics and America's Campaign to Create a Master Race. Dialog Press. ISBN 0914153307.
  4. ^ a b Connell, W.; Gardaphé, F. (2010). Anti-Italianism: Essays on a Prejudice. Springer. p. 48. ISBN 9780230115323.
  5. ^ Brigham 1923, 80-86; Yerkes 1921, 785
  6. ^ "Testing For Order And Control In The Corporate Liberal State", Clarence J. Karier, pages 108-137, Roots of Crisis: American Education in the Twentieth Century, ed. C. J. Karier, P. Violas, J. Spring. Page 112 here. See also below, Autobiography of Robert Mearns Yerkes, 1930.
  7. ^ Almost Human, 1924.
  8. ^ Gregory A. Kimble, C. Alan Boneau, Michael Wertheimer. 1996. Portraits of pioneers in psychology, Volume 2. Routledge. ISBN 1-55798-345-3.
  9. ^ Charles Earle Funk, What's the Name, Please?, Funk & Wagnalls, 1936.
  10. ^ "Yerkes National Primate Research Center".

General references[edit]

  • Yerkes, R M (2000), "Creating a chimpanzee community. 1963", The Yale Journal of Biology and Medicine, 73 (1–6), pp. 221–34, PMID 11765942
  • Yerkes, R M (1961), A History of Psychology in Autobiography, 2, pp. 381–407
  • Stark, B P (1985), "The Robert Mearns Yerkes papers", The Yale University Library Gazette. Yale University. Library, 59 (3–4), pp. 162–7, PMID 11618320
  • Haraway, D (1979), "The biological enterprise: sex, mind, and profit from human engineering to sociobiology", Radical History Review, Spec (20), pp. 206–37, doi:10.1215/01636545-1979-20-206, PMID 11615095
  • Burnham, J C (1972), "Thorndike's puzzle boxes", Journal of the History of the Behavioral Sciences (published Apr 1972), 8 (2), pp. 159–67, doi:10.1002/1520-6696(197204)8:2<159::AID-JHBS2300080202>3.0.CO;2-P, PMID 11609710
  • ROOFE, P G (1965), "Significant Segments of the Herrick-Yerkes Correspondence Relative to Psychobiology and Their Personal Philosophies", Perspect. Biol. Med., 8 (2), pp. 196–209, doi:10.1353/pbm.1965.0007, PMID 14277643, S2CID 296350
  • Hilgard, E R (1965), "Robert Mearns Yerkes, May 26, 1876--February 3, 1956", Biographical Memoirs of the National Academy of Sciences, 38, pp. 385–425, PMID 11615455
  • CARMICHAEL, L (1957), "R. M. Yerkes, psychobiologist", Science (published September 13, 1957), 126 (3272), p. 498, Bibcode:1957Sci...126..498C, doi:10.1126/science.126.3272.498, PMID 13467232
  • CARMICHAEL, L (1957), "Robert Mearns Yerkes, 1876-1956", Psychological Review (published Jan 1957), 64 (1), pp. 1–7, doi:10.1037/h0049362, PMID 13408389
  • ELLIOTT, R M (1956), "Robert Mearns Yerkes: 1876-1956", The American Journal of Psychology (published Sep 1956), 69 (3), pp. 487–94, PMID 13354820

Further reading[edit]

  • Spiro, Jonathan P. (2009), Defending the Master Race: Conservation, Eugenics, and the Legacy of Madison Grant, Univ. of Vermont Press, ISBN 978-1-58465-715-6, lay summary (29 September 2010)

External links[edit]

  • Robert Mearns Yerkes papers (MS 569). Manuscripts and Archives, Yale University Library. [1]