Researchers used a specialized infrared lens to measure pupillary changes to participants watching erotic videos. Pupils widened most to videos of people who participants found attractive, thereby revealing where they were on the sexual spectrum from heterosexual to homosexual.
Researchers can control the behavior of monkeys by using pulses of blue light to very specifically activate particular brain cells. The findings represent a key advance for optogenetics, a state-of-the-art method for making causal connections between brain activity and behavior. Researchers say that similar light-based mind control could likely also be made to work in humans for therapeutic ends.