Harlow-"The Wire Experiment"
Psychologist Harry Harlow conducted several controversial experiments in the late 1960's using rhesus monkeys to demonstrate the effects of love. Harlow’s most famous experiment involved giving young rhesus monkeys a choice between two different "mothers". One was made of soft terrycloth, but provided no food. The other was made of wire, but provided food from an attached baby bottle. Harlow noted that once the baby monkeys were removed from their biological mothers shortly after birth and left with the two experimental "mothers" they all spent a significant amount of time with the cloth mother and only went to the wire mother when hungry. "This data makes it obvious that contact comfort is a variable of overwhelming importance in the development of affectionate response, whereas lactation is a variable of negligible importance," Harlow explained (1958).