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Harry F. Harlow

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 can 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 was born in 1905 in Fairfield, Iowa. Following his education at Stanford, where he earned his bachelor's degree and a Ph.D. in 1930, he began a long academic career at the University of Wisconsin. His teaching career spanned 44 years, beginning in 1930. 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 Harry 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. Drive-reduction 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 more cuddly surface. 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 monkeys' own childrearing abilities at maturity. Later, Harlow's student, Stephen Suomi, 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 and first presented in the early 1960s, later became controversial, but are still considered important developments in the area of child psychology.

Harlow served for many years as editor of the Journal of Comparative and Physiological Psychology. In 1960, he received the Distinguished Scientific Contributions Award from the American Psychological Association, and in 1967, he was awarded the National Medal of Science.

Doreen Arcus, Ph.D.

Further Reading

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

Additional topics

Psychology EncyclopediaFamous Psychologists & Scientists