摘要：AbstractOne common observation about time perception is that it is subjective, dependent on factors such as attention rather than only the objective passing of time measured by a clock. For example, unexpected and emotional events are often experienced as passing in slow motion, as if time subjectively expands. Such time dilation effects have been measured in the laboratory using 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 for the oddball occurs when the duration of the standard items in the sequence is relatively brief (Tse et al., 2004). One possible explanation for temporal expansion is that increasing the state of arousal increases the rate of internal clocks, which then leads to the accumulation of more “ticks” and, thus, longer perceived durations. Another possibility, however, is that mental processes in general (rather than just mental clocks) are more rapid or efficient during such events, leading to more cognitive processing and hence the impression of more time passing. Here, we investigated whether the amount of information processed for a briefly presented display changes when time is perceived as distorted. Specifically, we used an enumeration task in order to measure the amount of information accrual over time.In this experiment, there were two separate blocks of trials, with standard stimuli presented at a fixed duration of either 70 (compression condition) or 1050ms (expansion condition). Each standard stimulus was each made up of a variable number of green dots. On each trial, a red oddball stimulus of varying numerosity (1-14 items) was presented. The duration of the oddball varied on each trial in both the compression (30 to 150ms) and expansion (650 to 1250ms) conditions. Observers were instructed 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 the long standard stimulus duration blocks (point of subjective equality (PSE) ∼840ms) or compressed for the short standard stimulus duration blocks (PSE∼100ms). 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 amount of information accrual over an interval determines the perceived duration of the event. Overall, the results show that subjective time distortions are not just epiphenomenal, but can reflect real changes in sensory processing of the incoming stimulus. In other words, when time subjectively slows down during emotional events, it might allow for processing more information in the same objective temporal duration. Such short-term plasticity in information processing rate could be evolutionarily advantageous in optimizing perception and action during critical moments.
