Harlow's experiments were ethically controversial; they included creating inanimate wire and wood surrogate "mothers" for the rhesus infants.

[5] After a year at Reed College in Portland, Oregon, Harlow obtained admission to Stanford University through a special aptitude test.

[6] Harlow attended Stanford in 1924, and subsequently became a graduate student in psychology, working directly under Calvin Perry Stone, a well-known animal behaviorist, and Walter Richard Miles, a vision expert, who were all supervised by Lewis Terman.

He worked with the primates at Henry Vilas Zoo, where he developed the Wisconsin General Testing Apparatus (WGTA) to study learning, cognition, and memory.

Due to the nature of his study, Harlow needed regular access to infant primates and thus chose to rear them in a nursery setting, rather than with their protective mothers.

[15] This alternative rearing technique, also called maternal deprivation, is highly controversial to this day, and is used, in variants, as a model of early life adversity in primates.

Research with and caring for infant rhesus monkeys further inspired Harlow, and ultimately led to some of his best-known experiments: the use of surrogate mothers.

Psychologically speaking, these infants were slightly strange: they were reclusive, had definite social deficits, and clung to their cloth diapers.

[16] Noticing their attachment to the soft cloth of their diapers and the psychological changes that correlated with the absence of a maternal figure, Harlow sought to investigate the mother–infant bond.

In 1953, his colleague James Robertson produced a short and controversial documentary film, titled A Two-Year-Old Goes to Hospital, demonstrating the almost-immediate effects of maternal separation.

[19] Bowlby's report, coupled with Robertson's film, demonstrated the importance of the primary caregiver in human and non-human primate development.

Bowlby disagreed, claiming that the mother provides much more than food to the infant, including a unique bond that positively influences the child's development and mental health.

Harlow concluded that there was much more to the mother–infant relationship than milk, and that this "contact comfort" was essential to the psychological development and health of infant monkeys and children.

[20] Both groups gained weight at equal rates, but the monkeys raised on a wire-mother had softer stool and trouble digesting the milk, frequently suffering from diarrhea.

[21] Some of Harlow's final experiments explored social deprivation in the quest to create an animal model for the study of depression.

[22] 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 in Washington, D.C., August 31, 1958.

Harlow et al. reported that partial isolation resulted in various abnormalities such as blank staring, stereotyped repetitive circling in their cages, and self-mutilation.

[28] Isolates exposed to monkeys the same age who were reared normally "achieved only limited recovery of simple social responses".

[28] Opposed to this, when six-month isolates were exposed to younger, three-month-old monkeys, they achieved "essentially complete social recovery for all situations tested".

In the last of these devices, alternatively called the "well of despair", baby monkeys were left alone in darkness for up to one year from birth, or repetitively separated from their peers and isolated in the chamber.

"[37]: 458 Sigmund Freud can be credited for providing the foundation of mother and child relationships, that would soon be the inspiration and the starting point for Harlow's studies.

The Freudian hypotheses states that a partial component of sexual drives, orality, determines the choice of an object, mother's breast, driven by hunger.

By the time a child has been seen and diagnosed with reactive attachment disorder, several different mental health, medical, and developmental conditions need to be treated.

[42] Harlow's experiments gave psychologists experimental data for the causes and development of RAD, which helped reduce misdiagnosis.

"[46] Mason also published articles where he attempted to work through the issue between a scientist's wish to understand the natural world and the "rights" of animals to life and autonomy.

Stephen Suomi, a former Harlow student and supporter who now conducts maternal deprivation experiments on monkeys at the National Institutes of Health, has been criticized by PETA and members of the U.S.

Blum reported in her own writing that even Suomi felt that he had to wait until Harlow retired from the University of Wisconsin before he could shut down his unethical "pit of despair" projects; they had been causing him "nightmares".

[44] E. H. Eyestone, Chief of the Animal Resources Branch of the National Institutes of Health (NIH), expressed the concern of a review committee with the "pits of despair" experiments.

[50] Harry Harlow won a national medal of science based on his work with monkeys, in addition to being named the president of the American Psychological Association (APA).

[51] Writer and animal-rights proponent Grant Morrison has cited Harry Harlow and his experiments as partial inspiration behind the creation (with Andy Kubert and Frazer Irving) of Batman villain Professor Pyg.