Julia McClellan¹ (), Allison Allen², Nicolas Davidenko²; ¹Boston University, ²University of California, Santa Cruz

In Illusory Apparent Motion (IAM; Davidenko et al., 2017), randomly changing pixel arrays, refreshing at around 1.5Hz, give rise to illusory percepts of coherent apparent motion that can be perceptually controlled, for example by deliberately changing one’s perception of the direction of motion (Allen et al., 2022). However, mechanisms underlying the marked individual differences in the ability to perceive and control IAM have yet to be explored. Previous work has shown that perception can be biased in favor of imagined stimuli, especially in individuals with more vivid visual imagery (Keough and Pearson, 2018; Djikstra et al., 2021). The current study examined whether observers with more vivid visual imagery would be better at perceiving and controlling IAM. In an IAM task, participants (n=41) were presented with 8-second trials of IAM stimuli and asked to perceptually control the motion to move congruently with a previously shown vertical or horizontal arrow. After each trial, participants reported whether they successfully controlled the motion and provided a 1-5 rating of the motion’s vividness. We assessed three measures of participants’ mental imagery vividness by measuring participants’ (a) pupil size as they imagined bright or dark shapes, (b) performance in a mental rotation task, and (c) scores on an extended version of the VVIQ (Marks, 1973) that included 8 additional questions related to motion imagery (mVVIQ). We found that VVIQ and mVVIQ strongly predicted participants’ vividness of IAM (r = 0.55, p < .001 for VVIQ; r = 0.58, p < .001 for mVVIQ) but did not predict participants’ability to control IAM (r = 0.05, p> 0.5 for VVIQ; r = 0.05, p > 0.5 for m-VVIQ). Our results suggest that individual differences in self-reported vividness of visual imagery can account for the vividness of IAM, but not the ability to control it.