• Weird History

An Experiment Took Monkeys Away From Their Mothers To Prove, Scientifically, That Love Exists

You may have heard of Harry Harlow's Monkey Love Experiment. The American psychologist is famous for his research on rhesus monkeys and the effect that maternal contact has on developmental growth. Harlow's monkeys were critical to his research and social isolation experiments. While Harlow and his team came up with some interesting conclusions, their work had critics. Some thought his experiments were almost as inhumane as the Stanford Prison Experiment.

Harlow separated infant monkeys from their biological mothers to observe their attachment behaviors with surrogate mothers made out of metal and cloth. The monkeys were exposed to the surrogates in varying degrees. Harlow and his team also isolated the primates for different periods of time to measure their psychological development. Unsurprisingly, the longer the monkeys were separated from their surrogates or other infants, the more problems they experienced.

As a result of Harlow's psychological findings, the researchers determined that infants bond with their mothers for more than just food and safety. There are also emotional variables that link them together. His research helped boost support for adoption in the nature vs. nurture argument, concluding that love and affection were necessities for a healthy child.

  • Photo: Harry Harlow / Wikimedia Commons / Public domain

    Harlow's Monkey Love Experiments Proved The Importance Of Motherly Affection

    American psychologist Harry F. Harlow set out to examine how rhesus monkeys behaved when separated from their mothers. He wanted to determine how instrumental maternal contact and companionship were to a young primate's development, both socially and mentally.

    Harlow performed various experiments to see how the monkeys' attitudes and demeanor were affected when they were removed from their mothers and placed into isolating environments. He filmed their responses.

  • Harlow Separated Infant Monkeys From Their Mothers Hours After Birth

    Harlow removed infant monkeys from their biological mothers just hours after they were born. Initially, the babies were split between two types of surrogate mother machines. One was made of mesh wire and the other was made of wood covered in soft terrycloth.

    Each surrogate was the same size. Typically, both types of surrogate mothers were capable of nourishing the monkeys with milk, but in some experiments only the wire mothers dispensed milk.

  • Harlow Didn't Believe That The Infant Monkeys Would Have Issues With Surrogate Mothers

    Harlow was convinced that baby monkeys under the age of three months who were taken from their biological mothers would have little difficulty adjusting to their fake mothers. He didn't believe the mother/child bond occurred within the first 90 days of life. He wanted to prove that love for the mother was based on emotional needs, not physiological factors.

    Harlow also aimed to find out if the bond between a mother and child was dependent solely on the mother being a food source or whether other factors contributed to their connection.

  • Photo: Harry Harlow / Wikimedia Commons / Public domain

    The Infant Monkeys Preferred The Cloth Mothers Even When The Wire Ones Provided Milk

    Both types of surrogate mothers were capable of nourishing the monkeys with milk. Harlow discovered that monkeys who could choose between the two surrogates preferred the terrycloth mothers, even when milk was solely provided by the wire mothers.

    The experiment revealed that the mother/infant bond was not predicated by nourishment.