Deprimerende

First Harlow took a group of newborn rhesus macaque babies and put them in a cage with the two surrogate mothers: the wire mother full of food, the cloth mother with an empty breast and a sweet smile. After the initial trauma, something amazing started to happen. Within days, the baby macaques transferred their affections from the real mother, who was no longer available, to the cloth surrogate.

The cloth mother, however, had no milk, so when the youngsters were hungry, they would dart over to the chicken-wire mother and then run back to the safety of the soft towel. Harlow graphed the mean amount of time the monkeys spent nursing versus cuddling. The disparity in favor of cuddling, he wrote, was "so great as to suggest that the primary function of nursing . . . is that of insuring frequent and intimate body contact of the infant with the mother."

...
Here is where Harlow began to earn his darker reputation. Here is where he stepped from science into fairy tales. He made many of the iron maidens: Some rattled their children and stabbed them. No matter what the torture, Harlow observed, the babies would not let go. There is no partial reinforcement to explain this behavior; there is only the dark side of touch, the reality of primate relationships, which is that mothers can kill us even as they hold us.

Monkey love - The Boston Globe