A series of experiments (rhesus monkeys) conducted by Harry and Margaret Harlow showed that:

The experiments showed that:

The bond between a mother monkey and a baby monkey did not depend exclusevly on the satisfaction of basic needs such as food. Monkeys looked for confort, to calm down, to feel warm. The separation of a monkey baby from his mother whitout a good subrrogate that covers the affective part, generates disturbance in a monkey.

Explanation:

The experimets with mokeys intended to see the importance of the bond between a monkey baby and a mother.

The experiment was about separating baby monkeys from their biological mother, and puting a made of cloth mother with no food bottle and a wire made mother with a bottle of milk, to subrrogate the biological mother.

Monkeys show to prefer the cloth mother. even if it did not provide any food.

In the other expriment the monkeys that had acces to the wire mother showed to be more disturbed than the ones that were near the cloth mother.