Jaeseob Lim¹ (), Sang-Hun Lee¹; ¹Seoul National University

Visual perception and decision-making are shaped by past experiences. A well-known phenomenon in this domain is serial dependence, where current perceptions are assimilated to previous ones, potentially serving as an adaptive strategy to exploit temporal stability in the environment. If serial dependence is indeed adaptive, it should strengthen in more stable environments or contexts where perceptual and decisional targets remain relatively unchanged over time. To test this hypothesis, we designed a task in which participants made decisions about two types of Gabor patches. One served as the estimation target, requiring participants to memorize and reproduce its orientation after a delay, while the other was a context Gabor patch, requiring participants to judge the temporal change in its orientation. We manipulated the degree of orientation change in the context Gabor patch to influence participants’ internal representation of environmental stability over time. Our results showed that this manipulation significantly affected the serial dependence of the estimation target. Surprisingly, however, the direction of modulation was opposite to our initial hypothesis. Specifically, large orientation changes in the context Gabor patch—indicating an unstable environment—led to stronger serial dependence in the estimation target. This suggests that larger changes in the context might paradoxically stabilize the perceived target orientation over time. A possible explanation lies in the contrastive nature of the visual system, akin to phenomena such as the tilt and Ebbinghaus illusions. Substantial changes in the context could downplay perceived changes in the target, causing its orientation to appear closer to past orientations. This effect occurred even though participants were not explicitly attending to orientation changes in the target. These findings highlight the complex interplay between contextual dynamics and serial dependence in visual perception.

Acknowledgements: This research was supported by the National Research Foundation of Korea funded by the Ministry of Science and ICT (RS-2024-00435727, RS-2024-00349515, RS-2023-00276729)