The perception and meta-perception of time within and between modalities

Abstract

We are interested in how we perceive time and how we accumulate and use our internal representation of a temporal interval. The work described here examines the perception of short durations of time in visual and auditory stimuli and the subjects' knowledge of their performance over repeated trials. Subjects were presented with 2 intervals containing a stimulus of the same duration (1500ms or 3000ms). The stimuli were visual gratings or auditory tones or a combination of the two. Subjects initiated presentation of each interval with a button-press and released the button when they considered the stimulus to be half-way through; they then indicated their 'best estimate' of the pair. Each subject (n=6) performed 500 trails in the same order as each other for 8 different conditions. Data was analysed in terms of first/second interval; 'best'/'worst' Actual Observer estimate; 'best'/'worst' Ideal Observer estimate. From this we were able to judge both the subject's performance on the task and their insight into their own decisional 'noise' in an Ideal observer framework. Visual and audio-only conditions showed similar mean bisection-points and (moderate) order-effects but with significantly less variance for the audio judgment. Mixed-modality conditions indicated no systematic change in bisection-point but an overall reduction in variance. There was no evidence for a scalar effect of duration in any condition and metacognition of performance was consistently good across conditions. The presentation regime allowed examination of the accumulation of the internal representation of the interval and its effect on future performance which suggests subjects use the last 4 estimates in their current judgment. The data suggest that subjects integrate effectively across modalities to generate an internal estimate of time close to, but subjectively different from, the actual time to be judged. This interval is learned rapidly but constantly updated throughout the observation period.

Meeting abstract presented at VSS 2018