In the 1950s, Harry Harlow conducted a series of experiments with infant rhesus monkeys that fundamentally changed how science — and child-rearing — understood love, attachment, and human development.

The Wire vs. Cloth Mother

Infant monkeys were given two surrogate mothers: one made of wire that provided food, one made of soft cloth that provided no food. The infants spent the vast majority of their time clinging to the cloth mother — running to her when frightened, using her as a secure base to explore.

What It Proved

Attachment is not primarily about feeding — it is about contact comfort. The dominant theory of the time (that infants bonded with whoever fed them) was wrong. Warmth, softness, and physical closeness are the primary drivers of early attachment.

Implications

• Revolutionized childcare practices in orphanages and hospitals
• Provided biological basis for John Bowlby's Attachment Theory
• Showed that emotional deprivation — not just physical deprivation — causes lasting psychological damage

Legacy

Harlow's work is also considered ethically problematic today. The deprivation conditions he created caused severe and lasting trauma in the animals studied.

Reference:

Wikipedia: Harry Harlow

https://en.wikipedia.org/wiki/Harry_Harlow