The Cloth Mother

!Infant Rhesus Macaque in the Embrace of Its Mother

Image: Infant Rhesus Macaque in the Embrace of Its Mother, Rohit Sharma. CC BY-SA 4.0, via Wikimedia Commons.

On August 31, 1958, in Washington, D.C., the psychologist Harry Harlow stood before the American Psychological Association to give his presidential address. His title was "The Nature of Love." He opened by complaining that psychologists, who were supposed to study human feeling, had written almost nothing about love. Then he showed them his monkeys.

Back in his Madison lab, Harlow had taken infant rhesus monkeys from their mothers within hours or days of birth and given each one a pair of substitutes. Both were crude. A cylinder of wire mesh with a wooden head. The same cylinder again, padded with sponge rubber and sheathed in terry cloth, with a bulb behind it for warmth. In some cages the bottle was fixed to the wire. In others, to the cloth.

The monkeys did not hesitate. Babies whose milk came from wire went over, drank, and hurried back to the towel. Some fed while leaning across from the cloth, keeping a foot hooked on it. By Harlow's own charts, they spent many hours a day on the cloth figure and barely any on the wire one. When something frightened them, such as a mechanical toy that marched and beat a drum, they ran to the cloth mother and held on. After a while, with the cloth mother close by, some turned around and looked at the thing that had scared them.

What it overturned

To see why the room reacted, you have to know what most of them believed. In the 1950s, a great deal of American psychology treated a baby's bond to its mother as a side effect of feeding. The mother was loved because she relieved hunger, and the attachment was learned through reward. Harlow's cloth mother, who fed no one, broke that explanation. Comfort from touch, what he called "contact comfort," turned out to be a need of its own.

Across the Atlantic, the British psychiatrist John Bowlby was building attachment theory from a different direction, out of observations of children separated from their families. We have written about the long history of those bonds in [bonds before Bowlby](/blog/bonds-before-bowlby). Harlow's monkeys gave Bowlby's ideas something that the behaviorists of the day found hard to dismiss: a controlled experiment.

The part that is harder to tell

The famous image is the small monkey with its arms around a cloth figure. It is less often told what came after.

In later work, Harlow and his colleagues raised monkeys in complete social isolation for months, sometimes in a stainless steel chamber he called the "pit of despair." The animals came out profoundly damaged. Many rocked, clutched themselves and could not interact with other monkeys. Some of the females later became mothers and neglected or attacked their infants.

Those experiments did add to the evidence that early deprivation causes lasting harm. They are also a central reason later generations of scientists pushed for stricter rules on animal research. Harlow's own language did not help his reputation. He named his devices with grim jokes and wrote about his subjects with a coldness that many readers, then and now, found hard to accept.

Both things are true at once. The cloth mother experiment changed how science understood love and comfort, and it shaped how orphanages, hospitals and parents came to think about touch. The same laboratory inflicted suffering that we would not permit today. A history that keeps only the gentle photograph is not a full history.

What stayed

Strip the lecture down and one claim is left. A young animal wants comfort as badly as it wants milk, and given the choice, it picks the cloth. Plenty of parents could have told Harlow that. He proved it in a way the textbooks had to print, using animals who never agreed to any of it. The cloth figures are in a museum now. The monkeys are not, and they belong in the story too.