Does Perception of Time Alter Under Hypnosis?

Abstract

Does Perception of Time Alter Under Hypnosis? Greg Anson1,2, Alexa Srzich1,2, Jonathan Finch1 1Department of Sport and Exercise Science, University of Auckland 2Centre for Brain Research, University of Auckland Introduction: The aim of this study was to test the hypothesis that hypnosis distorts the brains capability to accurately estimate a fixed duration. Previous research was equivocal – some reports suggested duration would be overestimated under hypnosis. Typically non-hypnotised participants under estimate a fixed duration and the underestimation increases at longer durations. Methods: Ten (6 female) participants aged 19-24y were assessed for hypnotic susceptibility (Stanford Hypnotic Susceptibility Scale) prior to undertaking a time estimation task, under and without hypnosis. Half the participants performed the task under hypnosis first. After practice, each task required estimation of the duration of 5, 15, 30 and 60 second periods presented in a pseudo-random order. For each interval the participant, using a stopwatch (facedown) activated the start button to begin the trial and pressed the stop button when they estimated the duration to have ended. Results: Data for one participant were excluded because of an equipment failure during the experiment. As illustrated, errors (M, SD) in time estimation increased as the duration lengthened. As predicted, without hypnosis underestimation was greater at longer durations. Under hypnosis, the opposite effect occurred – overestimation increased at longer intervals. Discussion: Under hypnosis prospective time estimation results in an overestimation of the length of the interval being judged. Participants assessed as less susceptible to hypnotic suggestion demonstrated less distortion of time estimation. This result suggests that the influence of hypnosis on prospective time estimation and thus on brain activity is affected at least in part by an individual’s susceptibility to hypnotic suggestion, potentially a trait effect that may interact with the hypnotic process.