Partial and total isolation of infant monkeys

Beginning in 1959, 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. For the study, some of the monkeys were kept in solitary isolation for 15 years.[19]

In the total isolation experiments, baby monkeys would be left alone for three, six, 12, or 24[20][21] months of "total social deprivation". The experiments produced monkeys that were severely psychologically disturbed. Harlow wrote:

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 tried to reintegrate the monkeys who had been isolated for six months by placing them with monkeys who had been raised normally.[10][22] The rehabilitation attempts met with limited success. Harlow wrote that total social isolation for the first six months of life produced "severe deficits in virtually every aspect of social behavior".[23] Isolates exposed to monkeys the same age who were reared normally "achieved only limited recovery of simple social responses".[23] Some monkey mothers reared in isolation exhibited "acceptable maternal behavior when forced to accept infant contact over a period of months, but showed no further recovery".[23] Isolates given to surrogate mothers developed "crude interactive patterns among themselves".[23] 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".[24][25] The findings were confirmed by other researchers, who found no difference between peer-therapy recipients and mother-reared infants, but found that artificial surrogates had very little effect.[26]

Pit of despair

Harlow was well known for refusing to use conventional terminology, instead choosing deliberately outrageous terms for the experimental apparatus he devised. This came from an early conflict with the conventional psychological establishment in which Harlow used the term "love" in place of the popular and archaically correct term, "attachment". Such terms and respective devices included a forced-mating device he called the "rape rack", tormenting surrogate-mother devices he called "Iron maidens", and an isolation chamber he called the "pit of despair", developed by him and a graduate student, Stephen Suomi.

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. These procedures quickly produced monkeys that were severely psychologically disturbed, and used as models of human depression.[31]

Harlow tried to rehabilitate monkeys that had been subjected to varying degrees of isolation using various forms of therapy. "In our study of psychopathology, we began as sadists trying to produce abnormality. Today, we are psychiatrists trying to achieve normality and equanimity."[32](p458)

Criticism

Many of Harlow's experiments are now considered unethical—in their nature as well as Harlow's descriptions of them—and they both contributed to heightened awareness of the treatment of laboratory animals, and helped propel the creation of today's ethics regulations. The monkeys in the experiment were deprived of maternal affection, potentially leading to what we now refer to as "panic disorders".[33] University of Washington professor Gene Sackett, one of Harlow's doctoral students, stated that Harlow's experiments provided the impetus for the animal liberation movement in the U.S.[2]

William Mason, another one of Harlow's students who continued conducting deprivation experiments after leaving Wisconsin,[34] has said 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."[35]