Perceptual aberration and brain hemisphere reversal of foreperiod effect on time estimation.

An auditory warning signal of 3 seconds' duration was followed by tachistoscopic presentation of a single dark dot to either the left or the right visual field (N = 18). The warning signal was presented monaurally to the left or to the right ear. The duration of the warning signal constituted foreperiod. The task was verbal estimation of the duration of the dot. For those who showed little or no sign of aberration of personal body image, as detected by Chapman's Perceptual Aberration Scale, time estimation of dot duration tended to be longer when the warning signal was presented to the left ear than to the right ear. For those who showed substantial sign of such aberration, the laterality of foreperiod effect was reversed, so that time estimation of dot duration was longer for the right ear than for the left ear. There was no such hemispheric reversal in terms of visual field.