Love in Infant Monkeys

Harlow, H.F. (June 1959). "Love in Infant Monkeys", Scientific American.

Harlow used baby rhesus monkeys to yield insights into the origin of the infant's love for its mother and concluded that bodily contact comfort is a decisive variable in this relationship. For example, newborn monkeys preferred a surrogate "cloth" mother to a "wire" mother, and sought out the cloth mother in times of emotional stress. Other variables were also explored. A mother's rocking motion appeared to enhance affection, but less so than simple contact. Heat of the mother did not appear to be an important variable. Other visual, auditory, and olfactory stimulation may also play a role. Additionally, a critical period to attachment formation seems to be evident.