Effect of a time-slowing suggestion on performance accuracy on a perceptual motor task

Three female subjects were hypnotized and played a video-tennis game under alternating control and experimental conditions in a within-subjects ABABAB withdrawal design. During control phases, subjects played the game under conditions of hypnotic relaxation. Prior to experimental phases a suggestion for subjective time-slowing, and ball-slowing, was presented. The initial presentation of the time-slowing suggestion did not result in improved performance accuracy. However, for all subjects, the second and third presentation of the suggestion resulted in significantly more longer volleys during experimental periods as compared to control periods. Possible explanation of the processes underlying improved performance accuracy are discussed in light of the subjective reports of the participants.