Harlow monkey experiment
Summary
Harlow raised infant rhesus monkeys with a wire surrogate that gave milk and a cloth surrogate that gave none; the infants clung mostly to the cloth one. It shows attachment depends strongly on contact comfort, not just feeding, challenging the learning-theory view.
Detail
Meaning: Harry Harlow raised infant rhesus monkeys apart from their mothers with two artificial surrogates: a bare wire one fitted with a milk bottle and a soft cloth-covered one with no food. The infants spent most of their time clinging to the cloth surrogate and went to the wire one mainly to feed. The conclusion is that attachment depends strongly on contact comfort, not just on feeding. Monkeys reared in isolation later showed fear, withdrawal and abnormal social and parenting behavior, pointing to the importance of early social experience.
On the MCAT: A passage describes the two-surrogate setup and asks what the results show or which view they challenge. The answer is the learning-theory idea that attachment forms because the caregiver supplies food, a primary reinforcer. Questions may also ask about animal-research ethics or whether monkey findings generalize to humans.
Common confusion: Students confuse it with Ainsworth's Strange Situation, which classifies attachment styles in human infants. In Harlow's study the wire surrogate was the food source, yet the cloth one was preferred, so comfort outweighed food in shaping the infants' attachment behavior.
Sources
- Psychology (Myers)
- Psychology (Schacter, Gilbert, Wegner)
- Discovering Psychology (Hockenbury)
Written for the MCAT and checked before it was published. For study reference only. Spotted an error? Let us know.