People who find it easier to fall into a trance are more likely to have an imbalance in the efficiency of their brain's two hemispheres, researchers have speculated.
In order to check if there are differences between the brains of susceptible and unresponsive volunteers when they were awake during hypnosis activity, Peter Naish of the Open University in Milton Keynes, UK, used a standard test of hypnotic susceptibility to identify 10 volunteers of each type, reports New Scientist.
The test combines motor and cognitive tasks.
He then gave each volunteer a pair of spectacles with an LED mounted on the left and right side of the frame. The two LEDs flashed in quick succession, and the volunteers had to say which flashed first.
aish repeated the task until the gap between the flashes was so short that the volunteers could no longer judge the correct order.
The expert found that hypnotically susceptible volunteers were better at perceiving when the right LED flashed first than when the left one did. This suggested that the left hemisphere of their brain was working more efficiently.
On the other hand, the non-susceptible people were just as likely to perceive the right LED flashing first as the one on the left.
These differences in the balance of brain efficiency persisted when Naish tried to hypnotise both groups.
During hypnosis, the brains of those in the susceptible group seemed to switch "states", becoming faster at spotting when the left LED flashed first. Meanwhile, the efficiency of the hemispheres remained relatively even in the non-susceptible people. They didn't fall into a trance, but their performance on the task started to deteriorate.
The study ahs been published in Consciousness and Cognition.