Abstract
Brief, unexpected events are often experienced as passing in slow motion, as if time subjectively expands. Such time dilation can be measured in an oddball paradigm, in which an infrequent stimulus is perceived to last longer than the standard stimuli in the rest of the sequence. In contrast, time compression occurs when the duration of the standard items in the sequence is brief (Tse et al., 2004). Here, we investigated whether the rate of information processing changes when time is perceived as distorted. We presented standard stimuli of a fixed duration (either 70 or 1050 ms, in separate blocks), each made up of a variable number of green dots, along with a red oddball stimulus of varying numerosity (1-14 items) and duration (30 to 150 ms or 650 to 1250 ms, respectively). Observers had to count the number of dots within the oddball and to judge its relative duration with respect to the standards on that trial. Consistent with previous results, oddballs were reliably perceived as temporally distorted, either expanded for longer (average point of subjective equality: PSE ~ 840 ms) or compressed for shorter oddballs (PSE ~ 100 ms). On a single trial level, enumeration was more accurate when temporal expansion occurred (oddball erroneously judged longer than the standards) and worse when time was subjectively shorter (illusory compression of the oddball). The effect of temporal distortion was maximal for intermediate set sizes for which duration influences information accrual, beyond the subitizing range but still within the range of accurate counting. These findings provide strong evidence for an integration model of time perception, in which the rate of information accrual over an interval determines the perceived duration of the event.
Meeting abstract presented at VSS 2014