Abstract
Recently, a stimulus called Illusory Apparent Motion (IAM) was discovered by Davidenko et al. (2017) wherein pixel textures randomly refreshing at a rate of 1.5 Hz generate the appearance of coherent apparent motion. IAM is a maximally ambiguous multistable stimulus that observers may perceive as moving coherently in a countless number of patterns (e.g., translation, shear, rotation, expansion-contraction). The current set of studies explores observers’ ability to perceptually control the appearance of IAM. The first two experiments used paradigms similar to those used with other multistable stimuli. Experiment 1 (n = 99) used a motion-priming persistence task, based on the methods of Davidenko et al. (2017), while experiment 2 (n = 76) used a dynamic report task with no priming, based on the methods of Kohler et al. (2008). In both experiments, participants successfully controlled translational motion by ‘changing’ or ‘holding’ their percepts, indicating that observers are capable of perceptually controlling IAM, similar to other multistable stimuli. Having established this, Experiment 3 (n = 43) explored the breadth of participants’ ability to perceive and control motion in IAM by testing them on 14 types of translational, shear, rotating, and expanding-contracting motion patterns. Participants were able to perceive a wide variety of motion patterns but were limited in the motion patterns they could control. Finally, Experiment 4 (n = 82) aimed to quantify the influence of perceptual control in biasing perceptions of IAM by presenting participants with a motion nulling signal (at above and below each participant’s perceptual threshold) while they attempted to control the motion. We were successful in quantifying the strength of perceptual control of IAM relative to low-level motion signals. Collectively, these studies provide evidence for the breadth and strength of observers’ ability to perceptually control IAM.