Left hemisphere superiority for event-related potential effects of hypnotic obstruction

Twenty-two highly hypnotizable subjects were run in a visual target detection task which compared hypnotic obstruction of the left and right visual fields over separate blocks. The visual event-related potentials (ERPs) to non-target stimuli revealed that hypnotic obstruction reduced the P200 component to stimuli in the right hemifield, but did not affect P200 for stimulation in the left hemifield. The earlier P100 and N100 were also reduced to hypnotic obstruction but not as preferentially for either hemifield, while the P300 was not significantly changed. Right visual field left hemisphere P200 reduction predicted suppression of behavioral response (button press) to hypnotically obstructed targets in both hemifields. The results are discussed in terms of Farah's model of a left hemisphere mechanism for image generation, and how highly hypnotizable subjects might use this mechanism to comply successfully with the suggestion of a hallucinated visually opaque barrier.