The Iron Maiden was a special surrogate monkey mother Harlow had designed; she shot out sharp spikes and blasted her babies with air so cold and forceful the infant monkeys were thrown back against the bars of their cages, clinging and screaming. This, claimed Harlow, was an evil mother, and he wanted to see what would happen.
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.