Dissociating the sequential dependency of subjective temporal order from subjective simultaneity.

Renan Schiavolin Recio,Raphael Yokoingawa De Camargo,André Mascioli Cravo,Virginie Van Wassenhove

doi:10.1371/journal.pone.0223184

Abstract

The physical simultaneity between two events can differ from our point of subjective simultaneity (PSS). Studies using simultaneity judgments (SJ) and temporal order judgments (TOJ) tasks have shown that whether two events are reported as simultaneous is highly context-dependent. It has been recently suggested that the interval between the two events in the previous trial can modulate judgments both in SJ and TOJ tasks, an effect named rapid recalibration. In this work, we investigated rapid recalibration in SJ and TOJ tasks and tested whether centering the range of presented intervals on perceived simultaneity modulated this effect. We found a rapid recalibration effect in TOJ, but not in SJ. Moreover, we found that centering the intervals on objective or subjective simultaneity did not change the pattern of results. Interestingly, we also found no correlations between an individual’s PSS in TOJ and in SJ tasks, which corroborates other studies in suggesting that these two psychophysical measures may capture different processes.

Highlights

By living in a stream of continuous sensory stimulation, our brain has to infer whether incoming signals in different sensory modalities specify a common or a different cause in the external world [1,2,3,4,5]
We found a large inter-individual variability in the individual PSS (iPSS) observed in the temporal order judgment (TOJ) task (Fig 2A and 2B) with iPSS spanning from -200 to +200 ms
The range of inter-individual variability in the TOJ task was consistent with a prior assessment of iPSS distribution in AV temporal order [35] and the lack of correspondence between the point of subjective simultaneity (PSS) in TOJ and simultaneity judgments (SJ) was consistent with previous studies [20, 36,37,38]

Summary

Introduction

By living in a stream of continuous sensory stimulation, our brain has to infer whether incoming signals in different sensory modalities specify a common or a different cause in the external world [1,2,3,4,5]. A major principle that informs such decision is the spatial and temporal coincidence of sensory events: the closer in space and time multisensory events are detected to be, the likelier they will be considered to specify a common cause [6, 7]. In this context, understanding the rules by which simultaneity (favoring the integration) and temporal order (favoring the segregration) of multisensory events operate becomes essential.

Methods

Results

Conclusion