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The "Pit Of Despair" Was One Of The Most Unethical Experiments Of Modern Science


Tom Hale


Tom Hale

Senior Journalist

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist


Over the course of his career, Harry Harlow's experiments earned him both academic acclaim and public notoriety. Image credit: deanmoriarty44/

In a quest to understand the nature of depression and loneliness, an influential scientist in the late-1960s designed a scientific apparatus that’s more akin to a monkey torture device.

The Pit Of Despair

The experiment was developed by American psychologist Harry Harlow with the hopes of producing an animal model of depression to better understand the condition and potentially find possible treatments. A rhesus macaque monkey would be placed into a large vertical cone-shaped structure fashioned out of hard, cold stainless steel. The floor of the device was made from wire-mesh, allowing poop to drop out of the bottom. Within this "pit," the monkeys would be fed and given water, but ultimately left alone for weeks at a time.


Harlow named this device the “pit of despair.” As he explains in a 1969 paper [PDF], the idea was to reflect the emotional sensation felt by a human with severe depression: “Depressed human beings report that they are in the depths of despair or sunk in a well of loneliness and hopelessness. Therefore we built an instrument that would meet these criteria and euphemistically called it the pit, or the vertical chamber for those who find the term ‘pit’ psychologically unacceptable.”

Most monkeys would fall into a still and huddled state within a matter of days of being placed in the pit. Once removed from the device, the monkeys would not revert back to normal social behavior. Harlow explains in a 1971 study that monkeys subjected to the “pit of despair” for 30 days would not play, shied away from social interaction, and showed no signs of curiosity. The majority of the monkeys would simply remain still in a huddle position, clasping their own body with their hands. These "profound behavioral anomalies," in Harlow's words, would remain even months after being freed from the device. 

While Harlow argued that the device held "enormous potential” for the study of depression, it is unclear whether this particular avenue of research ever provided any real insights into clinical depression or offered any possible ways to treat it. 

Harry Harlow

Over the course of his lengthy career, which spanned from the 1930s right up to the 1970s, Harry Harlow achieved both academic acclaim and public notoriety. 


Born in 1905, he spent most of his working life at the University of Wisconsin–Madison where enjoyed a great amount of success in his career. Harlow remains one of the most cited psychologists of the 20th century, but his work has aroused more than its fair share of controversy, for obvious reasons.

Using macaques as his subject, he showed how parental bonds, caregiving, and companionship (what some might call “love”) in early life were hugely important for social and cognitive development. He also highlighted how an infant has a profound psychological yearning for affection with a parental figure that goes much deeper than a utilitarian desire for warmth, protection, and food.

Before Harlow, scientists and academics in the first half of the 20th century pushed the idea that parents should keep emotionally distant from their own children. To condition an individual to become a well-rounded adult, they believed crying babies should be left alone and ignored, rather than responded to. One prominent child psychologist even told parents to not kiss their children goodnight, but give them a nice firm handshake before bed. Harlow was one of the many prominent figures to challenge this paradigm. 

Towards the end of his career, Harlow's interests veered towards the scientific investigation of depression. It’s been said that he was driven to understand the condition due to his own experience with severe depression, which intensified following his wife’s death in 1971. He died in 1981, plagued by depression and alcoholism.

The Ethics of Animal Testing

To most, Harlow’s experiments were sadistic, unjustified, and exploitative. In the words of American literary critic Wayne C Booth: "Harry Harlow and his colleagues go on torturing their nonhuman primates decade after decade, invariably proving what we all knew in advance—that social creatures can be destroyed by destroying their social ties."

Harlow did not exactly shy away from this image of a cold-hearted experimenter, either. In a 1974 interview, he reportedly remarked: “The only thing I care about is whether the monkeys will turn out a property I can publish. I don't have any love for them. Never have. I really don't like animals. I despise cats, I hate dogs. How could you like a monkey?” 

Some have hinted that Harlow appeared to have taken pleasure in giving his devices vivid and purposely shocking names. Along with the “pit of despair,” he also created the "tunnel of terror," "the iron maiden," — named after a literal torture device — and "rape racks" — a device that forced female monkeys to have sex.

Clearly, PR was not his strong point. 


Nevertheless, Harlow continues to influence the way we see child development and helped to reshape orphanages, adoptions services, and child care in the latter half of the 20th century. Some have even argued that Harlow's work forced the scientific world to rethink the use of animals in research.

Certainly, his experiments would struggle to get past a university's ethics committee in the 21st century, but animal experimentation continues to be widely used in scientific research. According to statistics from the US Department of Agriculture, scientists in the US used 75,825 non-human primates for research in 2018.


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