Harry Harlow
Born 1905 · Age 120
American psychologist known for maternal-separation, contact-comfort and social isolation experiments on rhesus monkeys; long-time professor at the University of Wisconsin–Madison; influential and controversial in developmental and comparative psychology.
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Life & Career Timeline
Born in Fairfield, Iowa
Harry Frederick Israel (later Harlow) born to Mabel Rock and Alonzo Harlow Israel in Fairfield, Iowa; third of four brothers.
Attended Reed College for one year
Spent one year at Reed College in Portland, Oregon before obtaining admission to Stanford University through a special aptitude test.
Admitted to Stanford University
Entered Stanford University (initially an English major, soon switched to psychology) and began graduate training under Lewis Terman and others.
Accepted professorship at University of Wisconsin–Madison
Immediately after completing his doctoral dissertation Harlow took a faculty position at UW–Madison and began nonhuman primate research.
Developed the Wisconsin General Testing Apparatus (WGTA)
At Henry Vilas Zoo and UW laboratories Harlow developed the WGTA to study learning, cognition, and memory in primates.
Founded and renovated the Primate Laboratory
Acquired and renovated a vacant building near UW–Madison into the Primate Laboratory — one of the first dedicated primate research labs — training ~40 PhD students over time.
Begun nursery rearing (maternal deprivation) methodology
Chose to rear infant macaques in nursery settings (rather than with mothers) to standardize developmental access for experiments — foundational to later 'contact comfort' research.
Received Ph.D. from Stanford
Completed doctoral dissertation in psychology at Stanford University (supervised by Lewis Terman and others).
Changed surname from Israel to Harlow
Changed legal surname from Israel to Harlow after receiving his doctorate (reportedly at Terman's prompting).
Married Clara Mears (first marriage)
Married Clara Mears, a former student; they later had two children (Robert and Richard).
Established rhesus macaque breeding colony
Founded an in-house breeding colony of rhesus macaques to provide a supply of infant primates for longitudinal learning and development studies.
Head of Human Resources Research, U.S. Army (branch)
Served as head of the Human Resources Research branch of the Department of the Army from 1950 to 1952.
Served as consultant to Army Scientific Advisory Panel
Acted as a consultant to the Army Scientific Advisory Panel (dates around 1950s), advising on human resources and research matters.
Mentored prominent students (e.g., Abraham Maslow, Stephen Suomi)
Supervised graduate students who became influential (Abraham Maslow worked briefly with Harlow; Stephen Suomi became a key collaborator and student).
Elected to the National Academy of Sciences
Recognized by election to the United States National Academy of Sciences.
Head, Division of Anthropology & Psychology, National Research Council
Served as head of the Division of Anthropology and Psychology of the National Research Council from 1952 to 1955.
Received Howard Crosby Warren Medal
Awarded the Howard Crosby Warren Medal (American Psychological Association recognition).
Elected to American Philosophical Society
Elected to the American Philosophical Society (APS), a major scholarly honor.
President of the American Psychological Association
Served as APA president for the 1958–1959 term.
Published 'The Nature of Love' in American Psychologist
Address later published as 'The Nature of Love' (American Psychologist), presenting empirical support for contact comfort over feeding as the sole basis of attachment.
Delivered 'The Nature of Love' address (APA)
Delivered the address 'The Nature of Love' to the 66th Annual Convention of the American Psychological Association in Washington, D.C.; work summarized his surrogate mother experiments.
Reported behavioral assays: open-field and fear tests
Developed behavioral paradigms showing surrogate mothers functioned as security bases: monkeys clung to cloth surrogate, used it as a base for exploration and protection from fearful stimuli.
Began publishing on partial and total social isolation
Harlow and students began publishing systematic observations on partial and total social isolation effects in infant rhesus macaques (starting 1959).
Published early findings on surrogate 'cloth vs wire' mother experiments (period)
Through a series of experiments (culminating in 1958 address and later publications) Harlow demonstrated infant macaques preferred cloth surrogate mothers over wire surrogates even when wire provided food — foundational evidence for 'contact comfort'.
Documented physiological effects of contact deprivation
Reported that wire-mother reared monkeys suffered gastrointestinal problems (diarrhea, soft stool) interpreted as physiological manifestations of psychological stress from lack of contact comfort.
Published on development of affection in primates
Contributed influential work synthesizing findings about early social contact and affection (cited works from early 1960s).
Published on early social deprivation and later behavior
Published analyses and chapters on the effects of early social deprivation in monkeys, elaborating developmental consequences.
Published 'Total social isolation in monkeys' (PNAS)
Paper in Proceedings of the National Academy of Sciences documenting effects of total social isolation (3–24 months) including severe psychological disturbances.
Reported durations of total isolation (3, 6, 12, 24 months)
Published findings documenting severe social, emotional, and physiological damage produced by different durations of total social deprivation in infant macaques.
Awarded the National Medal of Science
Received the U.S. National Medal of Science for contributions to psychology and primate research.
Described and used provocative apparatus names (e.g., 'pit of despair')
Harlow and colleagues (including Stephen Suomi) designed severe isolation apparatus (nicknamed 'pit of despair') used to model depression in primates — later a focal point of ethical criticism.
Public controversy and criticism over ethics of experiments
By the late 1960s–1970s Harlow's deprivation experiments drew intense ethical criticism and helped spur public debate and changes in animal research regulations (Animal Welfare Act 1966 and later reforms).
Reported limited success of rehabilitation efforts
Published studies showing social rehabilitation of isolated monkeys had limited success and depended on the age and social conditions of reintroduction (e.g., 6-month isolates recovered better when exposed to younger 3-month monkeys).
Published 'Social Recovery by Isolation-Reared Monkeys' (PNAS)
Harlow & Suomi reported findings on social rehabilitation of isolation-reared monkeys and differential outcomes depending on reintroduction strategy.
Death of second wife Margaret Kuenne
Margaret Kuenne (child psychologist; Harlow's second wife) died after a prolonged struggle with cancer; her death precipitated Harlow's depression and ECT treatment.
Remarried Clara Mears (third marriage for Harlow)
Married his first wife Clara Mears again (they lived together in Tucson, Arizona until his death).
Received Gold Medal from American Psychological Foundation
Awarded the Gold Medal (American Psychological Foundation) recognizing lifetime contributions to psychology.
Public interview quote about research ethic and animals
In a 1974 interview Harlow made controversial remarks (e.g., 'The only thing I care about is whether the monkeys will turn out a property I can publish'), cited in later criticisms of his ethics.
Death in Tucson, Arizona
Harry F. Harlow died on December 6, 1981, in Tucson, Arizona; buried alongside Margaret Kuenne at Forest Hill Cemetery in Madison, Wisconsin.
Ranked 26th most cited psychologist of 20th century (survey)
A Review of General Psychology (2002) survey ranked Harlow as the 26th most cited psychologist of the 20th century (posthumous recognition of influence).
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