Eye movements confirm hypnosis

Though less obvious than giant red swirls in the eyes, a glassy gaze that jumps around in bizarre patterns may mark a fake-proof hypnotic trance, researchers report.

Though scientists found this ocular giveaway in just one woman, the results suggest that that hypnosis truly is an altered state of consciousness, says study coauthor Sakari Kallio of the University of Skövde in Sweden and the University of Turku in Finland.

Kallio and his colleagues studied a middle-aged, healthy and highly hypnotizable woman. Normally outgoing and chatty, when the woman heard “hypno,” she withdrew and fell quiet, says Kallio.

Because one of the most striking changes was the appearance of a diffuse, unblinking stare, the researchers measured a series of involuntary eye features, such as pupil reflexes and quick movements.

Under hypnosis, the woman’s pupils were smaller than in normal conditions. What’s more, she had an abnormal pattern of small eye movements, called saccades, toward a target. The woman’s saccades were shorter and scarcer under hypnosis, the team reports online October 24 in PLoS ONE.

“Her eye movements were so strange,” Kallio says. And he adds that the woman herself agrees: “She thinks her eyes are scary when she sees the videos later.”

A group of 14 people watched videos of the hypnotized woman and tried to copy her strange eye behavior. But they couldn’t, suggesting that these eye movements can’t be faked.

Because the results are from a single person, larger studies are needed to know what these strange eye movements represent, says Irving Kirsch, a psychologist at Harvard Medical School’s Beth Israel Deaconess Medical Center in Boston and the University of Plymouth in England. “It’s an interesting study,” he says, “but we’ll have to see if it’s generalizable.”