AmericanPsychologistPrimatologistEugenicist

Robert Yerkes

Robert Yerkes was a psychologist and primatologist known for intelligence testing and the Yerkes-Dodson law, but his eugenics advocacy led to controversy.

1. Overview

Robert Mearns Yerkes
Robert Mearns Yerkes

Robert Mearns Yerkes (May 26, 1876 - February 3, 1956) was a prominent American psychologist, ethologist, eugenicist, and primatologist. He is widely recognized for his pioneering work in intelligence testing and the field of comparative psychology, particularly his studies on human and primate intelligence, as well as the social behavior of gorillas and chimpanzees. Alongside John D. Dodson, Yerkes co-developed the Yerkes-Dodson law, which describes the relationship between arousal and performance. While his academic contributions were significant, Yerkes's advocacy for eugenics in the 1910s and 1920s, and the application of his intelligence tests to support discriminatory immigration policies, have drawn considerable criticism. Modern academics largely view his work as biased toward outmoded racialist theories, leading to the recent renaming of institutions associated with him due to his controversial legacy. Yerkes himself stated his name was pronounced YerkesYUR-keezEnglish.

2. Early Life and Education

This section details Robert Yerkes's formative years, his academic pursuits, and the early influences that shaped his career in psychology and animal behavior.

2.1. Childhood and Education

Robert Yerkes was born on May 26, 1876, in Breadysville, Pennsylvania, a rural area near Ivyland, Pennsylvania. Growing up on a farm, Yerkes sought to escape the demanding life of a rural farmer and initially aspired to become a physician. With financial assistance from an uncle, he attended Ursinus College from 1892 to 1897. Upon graduation, he received an offer from Harvard University for graduate studies in biology. Opting for Harvard over medical training in Philadelphia, Yerkes pursued his academic interests there. While at Harvard, he developed a strong interest in animal behavior, which led him to defer further medical training to focus on comparative psychology. He earned his Ph.D. from the Psychology Department in 1902, where he studied under Hugo Münsterberg.

2.2. Early Career

The initial stages of Yerkes's professional life were significantly influenced by the debts he incurred during his education. After graduating from Harvard, he accepted a position at the university as an instructor and assistant professor in comparative psychology. To supplement his income for several years, he taught general psychology during the summers at Radcliffe College. He also took on a part-time role as the director of psychological research at the Boston Psychopathic Hospital in Boston, Massachusetts. In 1907, Yerkes published his first book, The Dancing Mouse, A Study in Animal Behavior. During this period, he became friends with John B. Watson, a future behaviorist, with whom he exchanged ideas and collaborated. Yerkes was also a member of the Wicht Club from 1903 to 1911. From 1921 to 1925, he served on the board of trustees of Science Service, now known as Society for Science & the Public. He was elected to the American Academy of Arts and Sciences in 1915, the National Academy of Sciences in 1923, and the American Philosophical Society in 1936. He also became a professor at University of Minnesota in 1917.

3. Academic and Professional Contributions

Robert Yerkes made significant research contributions across various academic fields, notably in psychology and primatology, pioneering methods for studying intelligence and animal behavior.

3.1. Comparative Psychology and Intelligence Testing

Yerkes was a pioneer in the study of both human and primate intelligence, laying the foundation for comparative psychology. His early research encompassed a wide range of animal species, from invertebrates to vertebrates, including mice, mammals, and other organisms, focusing on areas such as intelligence, learning, and perception. This broad approach helped establish comparative psychology as a distinct field. He was instrumental in the development of methodologies for intelligence testing, which later found widespread application.

3.2. Primatology and Primate Research

Yerkes harbored a profound and enduring fascination with the study of chimpanzees, which became a cornerstone of his research. His initial foray into primate studies involved purchasing two chimpanzees, a male bonobo named Chim and a female common chimpanzee named Panzee. He brought them into his home, where he observed them engaging in behaviors such as eating with a fork at a miniature table. His summer spent with Chim was particularly memorable and was chronicled in his 1924 book, Almost Human. In 1924, Yerkes visited Rosalía Abreu's extensive primate colony in Cuba, which was notable for being the first successful captive chimpanzee breeding facility. He was accompanied by Harold C. Bingham, Josephine Ball, and Chim, though Chim unfortunately died during this visit. Yerkes returned from Cuba with valuable advice from Abreu on raising and observing chimpanzees independently.

In 1924, Yerkes was appointed as a professor of psychobiology at Yale University, a field he helped to establish. 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. These roles helped him establish close relationships with officers from Rockefeller philanthropic foundations, which later enabled him to solicit substantial funds for his chimpanzee projects. With this funding, he founded the Yale University Laboratories of Primate Biology in New Haven, Connecticut, and subsequently established the Anthropoid Breeding and Experiment Station in Orange Park, Florida in 1929. The artificial language Yerkish, designed for communication with primates, was developed at the Yerkes Laboratories of Primate Biology. Yerkes retired from his directorship position in 1942 and was succeeded by Karl Lashley. He retired from teaching at Yale in 1944. Following Yerkes's death, the laboratory was relocated to Emory University in Atlanta, Georgia, and was subsequently renamed the Yerkes National Primate Research Center. Yerkes also initiated ecological surveys of great apes, dispatching Henry W. Nissen in 1931 to study chimpanzees and Harold C. Bingham in 1932 to research mountain gorillas in Africa.

3.3. Yerkes-Dodson Law

In collaboration with John Dillingham Dodson, Robert Yerkes developed the Yerkes-Dodson law. This psychological principle describes an empirical relationship between arousal and performance, positing that performance increases with physiological or mental arousal, but only up to a certain point. When levels of arousal become too high, performance decreases. The law suggests that for simple tasks, performance improves with increased arousal, while for complex tasks, an optimal level of arousal is lower.

4. World War I Contribution

During World War I, Robert Yerkes played a significant role in the American war effort by developing and implementing large-scale intelligence tests for military recruits.

4.1. Army Alpha and Beta Tests

In 1917, Robert Yerkes served as the president of the American Psychological Association (APA). Under his leadership and influence, the APA initiated several programs dedicated to supporting the war effort during World War I. As the chairman of the Committee on the Psychological Examination of Recruits, Yerkes spearheaded the development of the Army Alpha and Army Beta Intelligence Tests. These were groundbreaking as the first nonverbal group intelligence tests designed for mass administration. These tests were administered to over 1 million United States soldiers during the war, with some sources indicating the number exceeded 1.7 million personnel. Although Yerkes asserted that these tests measured inherent "native intelligence" rather than educational background or training, this claim has been difficult to substantiate, especially given the nature of some questions. For example, Question 18 of Alpha Test 8 asked: "Velvet Joe appears in advertisements of ... (tooth powder)(dry goods)(tobacco)(soap)."

5. Eugenics and Social Impact

Robert Yerkes's involvement with the eugenics movement and the social implications of his research represent a controversial aspect of his legacy, drawing significant criticism for their impact on racialist theories and social policies.

5.1. Support for Eugenics

Beginning in the 1910s and 1920s, Robert Yerkes became a vocal proponent of eugenics. He utilized the results of his intelligence tests, such as the Army Alpha and Beta, to support his eugenic arguments. He claimed that these tests measured an individual's innate intelligence, independent of their education or training. Based on these test results, Yerkes contended that recent immigrants, particularly those from Southern and Eastern Europe, scored considerably lower than earlier waves of immigration from Northern Europe. This interpretation contributed to the prevailing eugenic narrative of the time. Yerkes was appointed as an "Expert Eugenic Agent" to The House Committee on Immigration and Naturalization, where his work played a role in the creation of the discriminatory National Origins Formula. In his introduction to Carl C. Brigham's A Study of American Intelligence, a book that helped popularize eugenics in the U.S., Yerkes explicitly stated that "no one of us as a citizen can afford to ignore the menace of race deterioration." He was also a member and chairman of the Committee on Inheritance of Mental Traits, which was part of the Eugenics Record Office, an organization founded by Charles Benedict Davenport, who had been Yerkes's former teacher at Harvard.

5.2. Criticism and Controversy

Yerkes's research, particularly his intelligence testing and its application, has faced extensive criticism and debate. Modern academics largely consider his works to be biased toward outmoded racialist theories. The results he presented from the Army Alpha and Beta tests, which purported to show lower intelligence among certain immigrant groups, were later criticized for clearly measuring acculturation rather than innate intelligence. Critics pointed out that the test scores correlated almost exactly with the number of years individuals had spent living in the United States, indicating that the tests were culturally biased and favored those with more exposure to American schooling and culture. The lasting impact of Yerkes's work contributed significantly to American xenophobia and anti-immigrant sentiment. His findings were used as a key eugenic justification for the implementation of harsh and racist immigration restrictions in the United States, shaping policies that had profound and detrimental effects on immigrant communities.

6. Legacy and Evaluation

Robert Yerkes's legacy is complex, marked by both significant academic contributions to psychology and primatology, and profound controversy due to his advocacy for eugenics and its social repercussions.

6.1. Renaming of Primate Research Center

In April 2022, Emory University made the decision to remove Robert Yerkes's name from the National Primate Research Center. This action followed a recommendation from Emory's Committee on Naming Honors, which conducted a review and concluded that the name should be changed due to Yerkes's historical support for eugenics. Effective June 1, 2022, the institution, formerly known as the Yerkes National Primate Research Center, was officially renamed the Emory National Primate Research Center. This renaming reflects a broader reassessment of historical figures and their associations with controversial ideologies.

6.2. Historical Assessment

The historical assessment of Robert Yerkes's career presents a mixed evaluation. On one hand, he is recognized for his pioneering contributions to comparative psychology and primatology, including the establishment of significant research facilities and the development of the Yerkes-Dodson law. His work advanced the scientific understanding of animal behavior and intelligence. On the other hand, his fervent support for eugenics and the application of his intelligence tests to justify discriminatory social policies, particularly those impacting immigration and promoting racialist theories, cast a long shadow over his achievements. Critics emphasize that his methodologies were flawed and culturally biased, leading to harmful societal consequences. The decision by Emory University to rename the primate research center previously bearing his name underscores the modern academic and public rejection of the eugenic ideologies he espoused, highlighting the critical need to acknowledge the ethical and social impacts of scientific research.

7. Publications

Robert Yerkes authored and co-authored numerous books and academic papers throughout his career. His major publications include:

  • 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