Charles T. Demczuk¹ (demczuk.5@osu.edu), Sam Clarke², Sami R. Yousif¹; ¹The Ohio State University, ²University Of Southern California

The visual input that you receive changes constantly, yet your experience of the world feels relatively stable. How? Some have suggested that the visual system benefits from stabilization mechanisms like serial dependence, which adaptively biases all input towards the previous input. But at what stage does this supposed stabilization occur? Are these processes truly perceptual in nature? Here, we provide evidence that serial dependence may not be. We tested serial dependence across two domains — number, which has clear perceptual grounding, and coin value, argued to be paradigmatically imperceptible — using four distinct paradigms: sequential forced-choice, simultaneous forced-choice, estimation with and without feedback. Critically, the latter two paradigms inherently involve more complex cognitive processes at the decision stage, whereas the former two may not. For number, we found significant serial dependence across paradigms, with one exception: the simultaneous presentation condition, in which the reference and probe are compared directly. Effect sizes were influenced by task type, with estimation tasks producing (much) stronger effects than forced-choice tasks. For value, the story was strikingly similar — neither forced-choice task produced a significant effect, yet both estimation tasks did. Collectively, these findings provide two reasons to believe that serial dependence is not a perceptual phenomenon. First, if serial dependence were perceptual, it is unclear why the effects would vary so dramatically across paradigms; comparison tasks should yield reliable effects. Second, if serial dependence were perceptual, it is unclear why the effects would occur for a feature that is paradigmatically imperceptible (value). That these effects emerged so consistently across (substantively distinct) domains — and varied so predictably across paradigms — casts doubt on the canonical view that serial dependence is a perceptual phenomenon. This opens the door to redefining what serial dependence is and what it is not.