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Poster A in Poster Session A: Tuesday, August 4, 9:30 – 11:15 am, Kimmel Center, Shorin & Rosenthal Rooms

Revealing the geometry of duration space

Camille L. Grasso¹, Ladislas Nalborczyk², Virginie van Wassenhove³; ¹Wake Forest University, ²CNRS, ³CEA/DRF/Joliot, NeuroSpin; INSERM; Université Paris-Saclay

Presenter: Camille L. Grasso

Is there a geometry of time in the human mind? Here, we asked whether the experience of duration can be reduced to a simple mental timeline, or whether it is better described as a richer representational space. To address this question, we tested the same participants in two experiments: a behavioural similarity judgement task, in which participants rated the similarity of duration pairs, and an electroencephalography (EEG) experiment in which they detected oddball durations in a sequence. Behavioural and EEG data were used to construct representational dissimilarity matrices, whose geometry was compared against theoretical models of duration organisation. Behavioural similarity judgements revealed a three-dimensional duration space structured by monotonic magnitude, contextual encoding, and a periodic component. These three dimensions were jointly consistent with a latent generalised helical model, which provided excellent fit to the behavioural data. At the neural level, the geometry unfolded dynamically in two successive stages: a strong logarithmic encoding of durations peaking around 150 ms after duration offset, followed by a spring-like geometry, converging with the behavioural structure, from around 300 ms onward. Together, these findings support a multidimensional and dynamic representational geometry of duration.

Topic Area: Methods, Tools, Theory & Neural Coding