The Similarities Between Sub-second And Supra-second Time Perception Processing:Two ERP Studies

In the field of time psychology,there is still controversy about whether there is a "common mechanism" or "distinct mechanism" underlying the temporal processing of durations in the range of sub-second and supra-second.Thus,in this study,a typical temporal discrimination task and event-related potentials(ERP)technology were used to explore the dynamic patterns of the processing of sub-second and supra-second temporal perception.In Experiment 1,subject was presented with two gray ellipses in each trial.The presentation time of the first ellipse(standard interval,SI)was fixed at 500 ms,and the presentation time of the second ellipse(comparative interval,CI)was 200ms/ 350ms/ 500ms/ 650ms/ 800ms(5 kinds of CI conditions were randomly presented).Subjects were asked to judge whether the CI was longer or shorter than the SI.The behavioral results showed that the average subjective equivalence point(PSE)was 562 ms.The ERP results showed that the contingent negative variation(CNV)amplitude was significantly more negative when the CI was longer than the SI or closer to SI(500ms).Furthermore,CNV peak latency extended with the increased of the CI and the differences of CNV latency induced by 500 ms,650ms and 800 ms were not significant.No major effect or interaction effect of N1 or P2 was found.In Experiment 2,the SI was fixed at 2000 ms,and the CI was 1400ms/ 1700ms/ 2000ms/ 2300ms/ 2600ms(5 kinds of CI conditions were randomly presented).The behavioral results showed that the average subjective equivalence point was 1893.8ms.The ERP results showed that the CNV amplitude was significantly more negative when the CI was longer than the SI or closer to SI(2000ms).Besides,CNV peak latency extended with the increased of the CI and the differences of CNV latency induced by 2000 ms,2300ms and 2600 ms were not significant.No major effect or interaction effect of N1 or P2 was found.Taken together,the following conclusions were drawn:1.There was an underestimation in the sub-second perception processing,and anoverestimation in the supra-second perception processing.2.In terms of the dynamic characteristics,the sub-second and supra-second timeprocessing mechanisms have similarities in multiple stages of the theory of scalartiming model.3.CNV amplitude changed with the length of the CI,as well as the degree of closenessbetween the CI and the SI,which may reflect the comparison process between thecurrent comparison duration and the standard duration in memory.4.CNV peak latency increased significantly with the increased of CI and then stoppedwhen the current duration reached the memorized SI(500ms/2000ms),which mayreflect the decision-making process of temporal discrimination.