Harry Harlow
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| Dr. Harry Harlow | |
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 Harry Harlow
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| Born | October 31, 1906 Fairfield, Iowa, USA |
| Died | December 6, 1981 |
Harry Frederick Harlow (October 31, 1905–December 6, 1981) was an American psychologist best known for his maternal-deprivation and isolation experiments on rhesus monkeys, which demonstrated the importance of care-giving and companionship in the early stages of primate development. He conducted most of his research at the University of Wisconsin, where he worked for a time with humanistic psychologist Abraham Maslow.
Some of Harlow's experiments involved rearing infant macaques in isolation chambers that prevented them from having any contact with other monkeys or human beings. The monkeys were left alone for up to 24 months, and emerged severely disturbed. [1] The experiments were controversial, with some researchers citing them as factors in the rise of the animal liberation movement. Willam Mason, who worked with Harlow, told writer Deborah Blum that Harlow "kept this going to the point where it was clear to many people that the work was really violating ordinary sensibilities, that anybody with respect for life or people would find this offensive. It's as if he sat down and said, 'I'm only going to be around another ten years. What I'd like to do, then, is leave a great big mess behind.' If that was his aim, he did a perfect job." [2]
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[edit] Education and career
Born Harry Israel on Halloween night, he changed his name to Harry Harlow in 1930. He earned his B.A. and Ph.D. from Stanford University, and did his research primarily at the University of Wisconsin where he worked for a time with humanistic psychologist Abraham Maslow.
[edit] Surrogate mother experiment
In his most popularized series of experiments, conducted between 1963 and 1968, Harlow offered young rhesus monkeys a choice between two surrogate "mothers." In the first group, the terrycloth mother provided no food while the wire mother did, in the form of an attached baby bottle containing milk. In the second group, the terrycloth mother provided food; the wire mother did not. It was found that the young monkeys clung to the terrycloth mother whether it provided them with food or not and that the young monkeys chose the wire surrogate only when it provided food. Apparently the terrycloth mothers provided something that was more valuable to the young monkeys than food. She was providing contact comfort. Harlow's interpretation was that the preference for the terrycloth mother demonstrated the importance of affection and emotional nurturance in mother-child relationships
Whenever a frightening stimulus was brought into the cage the monkeys ran to the cloth mother for protection and comfort no matter which mother provided them with food. This response decreased as the monkeys grew older.
When the monkeys were placed in an unfamiliar room with their cloth surrogates, they clung to it until they felt secure enough to explore. Once they began to explore they would occasionally return to the cloth mother for comfort. Monkeys placed in an unfamiliar room without their cloth mothers acted very differently. They would freeze in fear and cry, crouch down, or suck their thumbs. Some of the monkeys would even run from object to object, apparently searching for the cloth mother as they cried and screamed. Monkeys placed in this situation with their wire mothers exhibited the same behaviors that the monkeys with no mother accompanying them did.
Once the monkeys reached an age where they could eat solid foods they were separated from their cloth mothers for 3 days. When they were reunited with their mothers they clung to them and did not venture off to explore as they had in previous situations. Harlow claimed from this that the need for contact comfort was stronger than the need to explore.
The study also found that monkeys who were raised with either a wire mother or a cloth mother gained weight at the same rate. However, the monkeys that had only a wire mother had trouble digesting the milk and suffered from diarrhea more frequently. Harlow interpreted this to mean that not having contact comfort was psychologically stressful to the monkeys. Harlow did eventually try to cure the depressed symptoms visible in monkeys deprived of a real mother through various forms of therapy.
Critics of Harlow's claims have observed that clinging is a matter of survival in young rhesus monkeys, but not in humans, and have suggested that his conclusions, when applied to humans, overestimated the importance of contact comfort and underestimated the importance of nursing. (Mason, W.A. Early social deprivation in the nonhuman primates: Implications for human behavior. 70-101; in: Environmental Influences, D.C. Glass (ed.) New York: Rockefeller University and Russell Sage Foundation. 1968. Excerpt in: Stevens, M.L. Maternal Deprivation Experiments in Psychology: A Critique of Animal Models. 11; The American Anti-Vivisection Society. 1986. )
[edit] Scientific motivations
Harlow first reported the results of these experiments in "The nature of love," the title of his address to the sixty-sixth Annual Convention of the American Psychological Association, Washington, D. C., August 31, 1958. These studies were motivated by John Bowlby's World Health Organization-sponsored study and report, Maternal Care and Mental Health in 1950, in which Bowlby reviewed previous surveys of the effects of institutionalization on child development such as René Spitz's (Spitz, R. A., & Wolf, K. M. Anaclitic depression: an inquiry into the genesis of psychiatric conditions in early childhood. II. Psychoanalytic Study of the Child,(2),313-342. 1946.) and conducted his own surveys on children raised in a variety of settings.
Bowlby's report was quickly recognized by psychologists and policy-makers as an unrivaled contribution to the field of child development.[citation needed] In 1953, his colleague, James Robertson, produced a short and controversial documentary film titled A Two-Year-Old Goes to Hospital demonstrating the nearly immediate effects of maternal separation. Bowlby's report, coupled with Robertson's film, demonstrated to doctors and psychologists the clear importance of maternal care in humans, just as Dr. Benjamin Spock's 1946, The Common Sense Book of Baby and Child Care had already done for nearly everyone else, but Bowlby's theoretical conclusions generated much debate.
It was this debate, about the reasons behind the demonstrated and acknowledged need for maternal care, that was addressed by Harlow in his studies with the cloth and wire surrogates.
[edit] Earlier research
Overshadowed by his popularized studies on affection and his and his students' subsequent studies on environmental and social deprivation, Harlow's earlier studies are rarely mentioned. A few titles include:
The effect of large cortical lesions on learned behavior in monkeys. Science. 1950. Retention of delayed responses and proficiency in oddity problems by monkeys with preoccipital ablations. Am J Psychol. 1951. Discrimination learning by normal and brain operated monkeys. J Genet Psychol. 1952. Incentive size, food deprivation, and food preference. J Comp Physiol Psychol. 1953. Effect of cortical implantation of radioactive cobalt on learned behavior of rhesus monkeys. J Comp Physiol Psychol. 1955. The effects of repeated doses of total-body x radiation on motivation and learning in rhesus monkeys. J Comp Physiol Psychol. 1956.
[edit] Later research
From around 1960 onwards, Harlow and his students began publishing their observations on the effects of partial and total social isolation. Partial isolation involved raising monkeys in bare wire cages that allowed them to see, smell, and hear other monkeys, but provided no opportunity for physical contact. Total social isolation involved rearing monkeys in isolation chambers that precluded any and all contact with other monkeys.
Harlow et al reported that partial isolation resulted in various abnormalities such as blank staring, stereotyped repetitive circling in their cages, and self-mutilation. These monkeys were then observed in various settings. Some of the monkeys remained in solitary confinement for 15 years. A variation of this housing method, using cages with solid sides as opposed to wire mesh, but retaining the one-cage, one-monkey scheme, remains a common housing practice in primate laboratories today. (Reinhardt V, Liss C, Stevens C. Social Housing of Previously Single-Caged Macaques: What are the options and the Risks? Universities Federation for Animal Welfare Animal Welfare 4: 307-328. 1995.)
In the total isolation experiments baby monkeys would be left alone for 3, 6, 12, or 24[4][5] months of "total social deprivation." This procedure produced monkeys that were severely psychologically disturbed:
No monkey has died during isolation. When initially removed from total social isolation, however, they usually go into a state of emotional shock, characterized by ... autistic self-clutching and rocking. One of six monkeys isolated for 3 months refused to eat after release and died 5 days later. The autopsy report attributed death to emotional anorexia. ... The effects of 6 months of total social isolation were so devastating and debilitating that we had assumed initially that 12 months of isolation would not produce any additional decrement. This assumption proved to be false; 12 months of isolation almost obliterated the animals socially ...[1] Harlow was well known for refusing to use euphemisms and instead chose deliberately outrageous terms for the experimental apparatus he devised, including a forced mating device he called a "rape rack," tormenting surrogate mother devices he called "iron maidens," and in about 1971, an isolation chamber he called the "pit of despair" developed by him and a student, Steven Suomi, now director of the National Institute of Child Health and Human Development's Comparative Ethology Laboratory, at the National Institutes of Health. In the latter of these devices, alternatively called the "well of despair," baby monkeys were left alone in darkness for up to six weeks or repetitively separated from their peers and isolated in the chamber. These procedures quickly produced monkeys that were severely psychologically disturbed and declared to be valuable models of human depression.[6] The importance of Harlow's and his student's decade and half of experiments on monkeys at the University of Wisconsin was summarized by one of his many previous graduate students. He remarked that it was surprising how quickly others quit citing Harlow after his death.[7] Willam Mason, who worked with Harlow, told writer Deborah Blum that Harlow "kept this going to the point where it was clear to many people that the work was really violating ordinary sensibilities, that anybody with respect for life or people would find this offensive. It's as if he sat down and said, 'I'm only going to be around another ten years. What I'd like to do, then, is leave a great big mess behind.' If that was his aim, he did a perfect job."[2]
[edit] Notes
- ^ a b Harlow HF, Dodsworth RO, Harlow MK. "Total social isolation in monkeys," Proc Natl Acad Sci U S A. 1965.
- ^ a b Blum, Deborah. The Monkey Wars. Oxford University Press, 1994, p. 96.
- ^ Stephens, M.L. Maternal Deprivation Experiments in Psychology: A Critique of Animal Models. AAVS, NAVS, NEAVS, 1986, p. 17.
- ^ Harlow, H.F. Development of affection in primates. Pp. 157-166 in: Roots of Behavior (E.L. Bliss, ed.). New York: Harper. 1962.
- ^ Harlow, H.F. Early social deprivation and later behavior in the monkey. Pp. 154-173 in: Unfinished tasks in the behavioral sciences (A.Abrams, H.H. Gurner & J.E.P. Tomal, eds.) Baltimore: Williams & Wilkins. 1964.
- ^ Suomi, JS. "Experimental production of depressive behavior in young monkeys." Doctoral thesis. University of Wisconsin, 1971.
- ^ Gluck JP. Harry F. Harlow and animal research: reflection on the ethical paradox. Ethics Behav. 7(2):149-61. 1997.
[edit] See also
[edit] Further reading
- Blum, Deborah. The Monkey Wars. Oxford University Press, 1994, ISBN 0-19-510109-X
- Blum, Deborah. Love at Goon Park: Harry Harlow and the Science of Affection. Perseus Publishing, 2002, ISBN 0-7382-0278-9
- Slater, Lauren. Opening Skinner's Box: Great Psychological Experiments of the Twentieth Century. W.W. Norton & Company, 2004, ISBN 0-393-05095-5
- The Nature of Love (1958) - Harry Harlow, American Psychologist, 13, 573-685
- Harlow: Monkey Love Experiments - Adoption History
- Harry Harlow - A Science Odyssey: People and Experiments
- The early days: Harlow and 50 years of cruelty
- Harlow et al. "Total social isolation in monkeys." Proc Natl Acad Sci U S A. 1965 July; 54(1): 90–97.
- Scientific proof that we all need love - A summary of Harlow's work on motherly love.
- Deborah Blum: The Inventor of the Cloth Mother An article about Harry Harlow.
