For the first hour, they just talked. He was nervous; he’d never done this before. She was understanding, reassuring: let’s just lie down on the bed together, she said, and see what happens. Soon, events took their course: they were enjoying themselves so much they could almost forget about the wires leading out of his skull.

The year was 1970, and the man was a 24-year-old psychiatric patient. The woman, 21, was a prostitute from the French Quarter of New Orleans, hired by special permission of the attorney general of Louisiana. And they had just become part of one of the strangest experiments in scientific history: an attempt to use pleasure conditioning to turn a gay man straight.