Harry F. Harlow

An American psychologist whose major contributions to psychology arose from his work with rhesus monkeys.

Experimental and comparative psychologist Harry Harlow is best known for his work on the importance of maternal contact in the growth and social development of infants. Working with infant monkeys and surrogate mothers made of terrycloth or wire, Harlow concluded that extended social deprivation in the early years of life could severely disrupt later social and sexual behavior. Harlow also conducted important studies involving the behavior of prisoners of war during the Korean War, as well as work concerning problem solving and learning among primates.

Harlow, the youngest of four brothers, was born on October 31, 1905 in Fairfield, Iowa to Mabel Rock and Alonzo Harlow Israel. After one year at Reed College in Oregon, Harlow was admitted to Stanford, where he earned a bachelor's degree followed by a Ph.D. in 1930. After receiving his degree, Harlow began a long academic career at the University of Wisconsin (Madison), spanning 44 years. He also served as director of the university's Regional Primate Center from 1961–71. In his work with primates, Harlow developed what he called a “uniprocess learning theory,” which describes how primates learn through a succession of incorrect responses to stimuli.

When Harlow began his famous studies of attachment behaviors in rhesus monkeys, he was able to pit two competing theories of the development of affiliative behaviors against each other. Drivereduction approaches were based on the premise that bonds between mothers and children were nurtured by the fact that mothers provided food and warmth to meet the infant's biological needs. Attachment theorists, on the other hand, felt that the provision of security through contact and proximity were the driving factors in the development of attachment.

Harlow devised a series of ingenious studies in which infant rhesus monkeys were raised in cages without their natural mothers, but with two surrogate objects instead. One surrogate “mother” was a wire form that the monkey could approach to receive food. Another form offered no food, but was wrapped in terry cloth so the infant could cling to a softer and cuddlier surface. Harlow then explored what happened when a large, threatening mechanical spider was introduced into the cage. The infant monkeys ran to the terry cloth surrogates, demonstrating that contact comfort was more important than just meeting basic hunger needs for the establishment of a relationship from which the infant might derive security.

In a series of related experiments, Harlow studied the effects of maternal and contact comfort deprivation across the monkey's lifespan, uncovering unexpectedly harmful effects of such deprivation on the monkey's own childrearing abilities at maturity. Later, Harlow's student, Stephen Suomi (1945–), and his colleagues demonstrated that these longstanding effects could be improved by introducing a nurturant “foster grandmother.”

Harlow's conclusions about maternal bonding and deprivation, based on his work with monkeys was first presented in the early 1960s. These conclusions later became controversial but are still considered important developments in the area of child psychology. Harlow received numerous awards including the Howard Crosby Warren Medal (1956), the Distinguished Scientific Contributions Award from the American Psychological Association (1960), the National Medal of Science (1967), and the Gold Medal from the American Psychological Association (1973). He served in the army as the head of the Human Resources Research branch (1950–52) and as a consultant to the Army Scientific Advisory Panel. He also was the head of the Division of Anthropology and Psychology of the National Research Council (1952–55), was president of the American Psychological Association (1958–59), and served for many years as editor of the Journal of Comparative and Physiological Psychology. Additionally, nearly 40 students received their Ph.D. under Harlow.

Harlow had four children with two wives, two children with Clara Mears, whom Harlow first married in 1932 and later remarried in 1972 after divorcing in 1946 and marrying Margaret Kuenne that same year. The couple had two children together before Margaret died of cancer in 1971. Harlow died in Tucson, Arizona on December 6, 1981 at the age of 76.



Harlow, Harry F. Learning to Love. New York: J. Aronson, 1974.

Harlow, Harry F. and Clara Mears. The Human Model: Primate Perspectives. Washington: V. H. Wiley, 1979.


Harlow, Harry F. “The Nature of Love.” American Psychologist 13, no. 12 (1958): 673–685.

van Rosemalen, Lenny., Frank C. P. van der Horst and Renévander Veer. “Of Monkey and Men: Spitz and Harlow on the Consequences of Maternal Deprivation.” Attach-ment & Human Development 14, no. 4 (2012): 425–437.


Herman, Ellen. “Harry F. Harlow, Monkey Love Experiments.” http://pages.uoregon.edu/adoption/studies/HarlowMLE.htm (accessed July 17, 2015).

Schultheis, Erin. “Harry F. Harlow.” http://muskingum.edu/~psych/psycweb/history/harlow.htm (accessed July 17, 2015).

WGBH. “Harry Harlow 1905–1981.” http://www.pbs.org/wgbh/aso/databank/entries/bhharl.html (accessed July 17, 2015).