[P2] Poster: Day 2

[P2-17] Modality-Specific Temporal Assimilation in a Bisection Task

*Gabriel Cafeu Brandão¹, Gustavo Brito de Azevedo¹, Peter Maurice Erna Claessens¹, André Mascioli Cravo¹ (1. Center for Mathematics, Computing and Cognition, Federal University of ABC (UFABC) (Brazil))

Keywords:

Time perception,Temporal bisection,Crossmodal integration,Distributed processing,Psychophysics

Time perception is fundamental to adaptive behavior, yet its neural mechanisms remain debated. While some models propose a centralized internal clock, others argue for distributed, modality-specific processing. This study tests these models by investigating whether the temporal assimilation effect, in which target intervals are underestimated after short distractors, generalizes across sensory modalities (auditory, visual, tactile). In Experiment 1 (n = 20), auditory targets paired with auditory or visual distractors revealed assimilation only when the distractor and target shared the same auditory modality. A significant main effect of distractor duration was found, F(1, 19) = 15.8473, p < .05, as well as a significant interaction effect, F(1, 19) = 19.2034, p < .05. In Experiment 2 (n = 20), auditory targets with frequency-varied auditory distractors (500Hz vs. 4000Hz) showed no significant modulation of assimilation. The distractor effect was present, F(1, 17) = 5.2168, p < .05, but no interaction, F(1, 17) = 1.5918, p > .05, indicating that modality, but not stimulus dissimilarity, modulated the effect. To test whether the modality effect in Experiment 1 was due to participants being able to inhibit visual processing, a novel tactile-vibratory device was developed and preliminarily validated through pilot testing (n = 2) to extend the paradigm to tactile-auditory pairings. We are recruiting 20 participants for a bisection task with tactile distractors (50- 217ms) and auditory targets. Data collection will test if assimilation persists cross-modally. If tactile distractors modulate auditory targets, this suggests supramodal temporal integration; the absence of this effect further supports the notion of distributed processing. Taken together, our findings raise questions about centralized models of time perception and suggest the possibility of modality-specific temporal encoding. The tactile extension may help clarify whether distributed timing mechanisms operate universally or vary across different sensory hierarchies.