Presentation Information
[P3-34]Lag adaptation and Bayesian calibration in tactile simultaneity perception
*Kyuto Uno1, Kaoru Amano1 (1. The University of Tokyo (Japan))
Keywords:
Lag adaptation,Bayesian calibration,Simultaneity perception,Timing perception,Tactile
Accurate perception of temporal relations between sensory events is essential for interacting with the environment. Lag adaptation—where repeated exposure to two signals in a fixed order shifts the point of subjective simultaneity (PSS) toward that order—has been robustly observed in vision, audition, and multisensory domains (e.g., Fujisaki et al., 2004). In contrast, tactile studies have reported an opposite effect—Bayesian calibration—where perceived intervals increase following exposure (Miyazaki et al., 2006). Notably, tactile studies have never adopted the canonical lag-adaptation protocol, where participants received stimulus pairs with a constant lag and then judged the simultaneity (SJ) or temporal order (TOJ) of test pairs with SOAs from an unbiased distribution. We introduced this protocol to the tactile modality to test whether the inconsistent results reflect a somatosensory peculiarity or different protocols. Results showed that the PSS shifted toward the adaptation lag in both tasks, revealing “tactile lag adaptation” for the first time. In separate experiments, we reproduced the protocol typical of earlier tactile studies by eliminating the separation between adaptation and test: participants performed SJ or TOJ of tactile pairs with SOAs from biased distributions. This protocol replicated Bayesian calibration, driving the PSS away from the prevalent lag. These findings resolve a long-standing controversy in temporal perception by demonstrating that the direction of aftereffects depends not on sensory modality but on the protocol. Our findings suggest that Bayesian calibration and lag adaptation reflect distinct yet complementary mechanisms; the former implements statistical inference, biasing perception away from frequently encountered delays, while the latter performs a recalibration, aligning perceptual simultaneity with consistent temporal patterns. Both processes appear essential in enabling flexible and context-sensitive temporal perception.