American psychologist Harry Harlow is known for his infamous social isolation research conducted on rhesus monkeys during the late 1950s and early 1960s. At his primate lab located at the University of Wisconsin-Madison, Harlow performed a series of experiments in which infant monkeys were raised by surrogate "mothers."
In different variations of the experiments, some of the mother monkeys were made entirely of wire while others were covered in a soft terrycloth. At the time, some researchers suggested that feeding was force behind the mother-child bond. The main idea behind this was that children love their caregivers because they provide food. What Harlow and his fellow researchers found was that the vital factor underlying an infant's love for its mother was contact comfort. The infant monkeys in Harlow's experiments preferred the soft terrycloth mothers over the wire mothers, even when the latter served as the source of food.
Harlow's experiments played an important role in changing our understanding of attachment, but they were also extremely controversial. The experiments were both shocking and cruel, particularly his later experiments that involved placing young monkeys in total social isolation. Most of his experiments are considered unethical by today's standards and the nature of his research contributed to concern and ethical regulations over how laboratory animals are treated.
Learn more about his life, career, and contributions to psychology in this Harry Harlow biography.