Harry F. Harlow

(1906 - 1981)

Compiled by Erin Schultheis (May 1999)

Harlow Biography
Time Line

Harry F. Harlow was an American Psychologist who provided a new understanding of human behavior and development through studies of social behavior of monkeys. His research contributions (in the areas of learning, motivation, and affection) have major relevance for general and child psychology.

Harlow obtained both his BA and PhD in Psychology from Stanford University. Upon completion of his PhD, Harlow joined the psychology staff at the University of Wisconsin (Madison). He was a modest, brilliant man who enjoyed spending time with students and took special pride in teaching introductory psychology courses. Nearly forty students obtained their PhD under his direction.

Professor Harlow's research developed an abundant supply of primate learning tests and tasks that became standards in the field. In general, Harlow wanted to prove to the psychology community that primate research could contribute to the understanding of important clinical issues without having to be molecular in nature. His theory hinged on the universal need for contact. Harlow's famous wire/cloth "mother" monkey studies demonstrated that the need for affection created a stronger bond between mother and infant than did physical needs (food).

Harlow was a member several Science and Psychological Associations, including the American Psychological Association, National Academy of Arts & Sciences, and Sigma Xi. He was a national lecturer and also a consultant to the Army's Scientific Advisory Panel. During his career, he was recognized with several distinctions, including: Howard Crosby Warren Medal (1956), National Medal of Science (1967), and Gold Medal from American Psychological Foundation (1973). Much of his primate research regarding social separation, affection, attachment, love, learning, and early life behaviors was published.

Harlow died in 1981, at the age of 75. His life work provided a developmental framework based on data results rather than convoluted theories with limited empirical support.

In Harlow's initial experiments, infant monkeys were separated from their mothers [visit this site] at six to twelve hours after birth and were raised instead with substitute or "surrogate" mothers made either of heavy wire mesh or of wood covered with cloth. Both mothers were the same size, but the wire mother had no soft surfaces while the other mother was cuddly covered with foam rubber and soft terry cloth. Both mothers were also warmed by an electric light placed inside them.

image In one experiment both types of surrogates were present in the cage, but only one was equipped with a nipple from which the infant could nurse. Some infants received nourishment from the wire mother, and others were fed from the cloth mother. Even when the wire mother was the source of nourishment (and a source of warmth provided by the electric light), the infant monkey spent a greater amount of time clinging to the cloth surrogate. These results led researchers to believe the need for closeness and affection goes deeper than a need for warmth.

These monkeys raised by the dummy mothers engaged in strange behavioral patterns later in their adult life. Some sat clutching themselves, rocking constantly back and forth; a stereotypical behavior pattern for excessive and misdirected aggression. Normal sexual behaviors were replaced my misdirected and atypical patterns: isolate females ignored approaching normal males, while isolate males made inaccurate attempts to copulate with normal females.

As parents, these isolate female monkeys (the "motherless mothers" as Harlow called them) were either negligent or abusive. Negligent mothers did not nurse, comfort, or protect their young, nor did they harm them. The abusive mothers violently bit or otherwise injured their babies, to the point that many of them died. Deprivation of emotional bonds to live mother monkeys (as infant monkeys) these (now adult) monkeys were unable to create a secure attachment with their own offspring. (Principles of General Psychology, 1980, John Wiley and Sons).

Harlow's research suggested the importance of mother/child bonding. Not only does the child look to his/her mother for basic needs such as food, safety, and warmth, but he also needs to feel love, acceptance, and affection from the caregiver. His findings show some long-term psychological physical effects of delinquent or inadequate attentiveness to child needs.

Harlow also did learning research with his monkeys. His theory, "Learning to Learn", described the ability of animals to slowly learn a general rule that could then be applied to rapidly solve new problem sets.

Harlow presented the monkey with two stimuli (a red block and a thimble, for example); one was predetermined "correct" and reinforced with food (red block) and the other was "incorrect" and not reinforced with food (thimble). After each selection, the objects were replaced and the monkey again chose a stimulus. Each trial reinforced the same stimulus (red block). The monkey had a 50% chance of being "correct" on each trial, however, he could increase his chances by adopting the win-stay, lose-shiftstrategy. For example, if the monkey chose the thimble and was not reinforced, he should shift to the red block for the reinforcer. If, however, he correctly selected the red block and was reinforced, he should stay with the reinforced stimulus and choose the same stimulus next time.

The monkey continued throughout a series of six trials with eight pairs of stimuli (learning sets). Harlow found the monkeys to be averaging approximately 75% correct responses by the sixth trial of the eighth set. He then began to look at the animal's behavior during the second trial. He found the monkeys to implement the stay or shift strategy on the second trial of the six-trial set, which means the animals did not relearn the strategy with each new stimuli set, they instead applied the rule they had already learned. After 250-plus trials, the monkeys were about 98% correct on the second through the sixth trials with each new stimuli set.

Harlow's learning research demonstrates that animals, like humans, are able to learn to apply strategies or rules to situations to help them solve problems.

Time Line
Born October 31 in Fairfield, Iowa Son of Lon and Mabel (Rock) Israel
30-44 Staff, University of Wisconsin at Madison; Married Clara Mears
39-40 * Carnegie Fellow of Anthropology at Columbia University
44-74 George Cary Comstock Research Professor of Psychology
46 Divorced Clara Mears; Married Margaret Kuenne
47-48 President, Midwestern Psychological Association
50-51 President of Division of Experimental Psychology, American Psychological Association
50-52 Head of Human Resources Research Branch of Department of Army
53-55 Head of Division of Anthropology and Psychology of National Research Council
56 * Howard Crosby Warren Medal
56-74 Director of Primate Lab, University of Wisconsin
58-59 President, American Psychological Association
59,65 Sigma Xi National Lecturer
1960 * Distinguished Psychologist Award, APA / Messenger Lecturer at Cornell University
61-71 Director of Regional Primate Research Center
64-65 President of Division of Comparative & Physiological Psychology, APA
67 * National Medal of Science
1970 Margaret (wife) died
71 Harris Lecturer at Northwestern University / Remarried Clara Mears, Children: 3 Sons, 1 Daughter
72 Martin Rehfuss Lecturer at Jefferson Medical College / * Gold Medal from American Psychological Foundation / * Annual Award from Society for the Scientific Study of Sex
74 University of Arizona (Tucson) Honorary Research Professor of Psychology
75 * Von Gieson Award from New York State Psychiatric Institute
76 * International Award from Kittay Scientific Foundation
Also Member of the following (dates not given):
Consultant to Army Scientific Advisory Pannel; American Philosophical Society; National Academy of Sciences; National Academy of Arts and Sciences ; Sigma Xi ; Phi Kappa Phi
1981 Died
* Denotes Awards and Honors

Harlow, H. F.; Zimmermann, Robert. Affectional responses in the infant monkey. Foundations of animal Behavior. (1996), xvi, 843, 376-387.
Harlow, H., et al. Social rehabilitation of separation-induced depressive disorders in monkeys. American Journal of Psychiatry. (1976), v. 133(11), 1279-1285.
Harlow, H., et al. Effects of maternal and peer separations on young monkeys. Journal of Child Psychology & Psychiatry & Allied Disciplines. (1976), v. 17(2), 101-112.
Harlow, H. Lust, latency and love: Simian secrets of successful sex. Journal of Sex Research. (1975), v. 11(2), 79-90.
Harlow, H. A variable-temperature surrogate mother for studying attachment in infant monkeys. Behavior Research Methods. (1973), v. 5(3), 269-272.
Harlow, H., et al. The sad ones: Studies in depression. Psychology Today. (1971), v. 4(12), 61-63.
Harlow, H., et al. Nature of love: Simplified. American Psychologist. (1970), v. 25(2), 161-168.

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