Schedule of Events | Symposia

Additive versus Multiplicative Temporal Dilation of Dynamic Visual Stimuli

Poster Session F - Tuesday, April 1, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Kezhen Qi¹ (kezhenqi2028@u.northwestern.edu), Alejandro Cruz¹, Abigail Yiru Liu¹, Marcia Grabowecky¹, Satoru Suzuki¹; ¹Northwestern University

Temporal dilation, the subjective elongation of perceived duration, has been explained by two competing theories: (1) the sensory-input-intensity theory, which links dilation to increased magnitude coding from dynamic or salient stimuli, and (2) the accumulator theory, which links dilation to the speeding of an internal clock. Our study aimed to reconcile these theories by examining temporal dilation effects in distinct contexts using a duration reproduction paradigm. In Experiment 1, we presented static, expanding, and contracting disks of nine durations (500–2000ms). Importantly, the total size change during each expansion/contraction was constant. Results revealed additive dilation, with the expanding/contracting stimuli lengthening reproduced durations by ~250ms irrespective of their durations. This aligns with the sensory-input-intensity theory as dilation was driven by sensory magnitude (i.e., the fixed total size change). Experiment 2 orthogonally varied stimulus duration and expansion/contraction rate. Results revealed multiplicative dilation, where dilation increased proportional to stimulus duration, with faster expansion/contraction rates yielding greater slope, suggesting that expansion/contraction speeds up temporal pulse accumulation, consistent with the accumulator theory. When we intermixed the trials from Experiments 1 and 2, the results surprisingly replicated, ruling out the hypothesis that the contextual manipulation changed the temporal dilation effect from additive to multiplicative. We noted that Experiment 1 (which yielded only an additive effect) did not include rapidly expanding/contrasting stimuli that lasted for long durations. The overall results suggest that, while the additive mechanism operates by default, the multiplicative mechanism is engaged when fast expansion/contraction persists for longer than a certain threshold duration.

Topic Area: PERCEPTION & ACTION: Other