Abstract
Are the neural mechanisms underlying time perception specific to each sensory modality or supra-modal? We found evidence for both in a time illusion that in a repeating item sequence, the first one appears to last longer ("debut chronostasis"). In a four-item sequence paradigm, debut chronostasis magtitude (DCM) was measured by a duration discrimination task comparing the first and the second items. We have previously found that visual debut chronostasis would occur only if the first item had variable duration across trials and disappear if it had constant duration. We explained the results with uncertainty of an internal duration template that could be perturbed by a variable-duration first item. Here we further tested whether the internal duration template is intra- or supra-modal. In Experiment 1 (N=19), the variable item was the first one (debut chronostasis expected); in Experiment 2 (N=8), the second one (no debut chronostasis expected). In both experiments, the modality of the first and the second items were V-V (visual), A-A (auditory), V-A, or A-V. Were intra-modal mechanisms exist, DCM would be stronger in the within- than in the cross-modal conditions in Experiment 1; Were duration templates entirely intra-modal, the certainty of the first-item duration in Experiment 2 would reduce DCM compared to Experiment 1 only in the within-modal conditions. Were debut chronostasis entirely a supra-modal, DCM would be the same in the within- and the cross-modal conditions in Experiment 1. The results showed that 1) in both experiments, DCMs were higher in within-modal conditions, suggesting an intra-modal stage of mechanisms and 2) when the duration of the first-item was constant in Experiment 2, DCMs in all four conditions of were lower than those in Experiment 1 by similar amount, suggesting the existence of supra-modal mechanisms. Thus, we found evidence for both intra- and supra-modal stages of time perception.
Meeting abstract presented at VSS 2018