When objects move on circular trajectories that could be described as orbiting, are they represented independently, as when translating linearly, or as parts of a composite system, akin to elements visibly affixed to a rotating structure? This fundamental question matters because representing a satellite as part of a rotating system implies that perception constructs composite representations, including internal references to anchor the system to the external present. We tested this composite representation hypothesis using a tracking task, predicting greater difficulty for rotational compared to translational motion along similar trajectories. Composite representations require additional computational steps to integrate internal and external references, unnecessary steps for independent tracking through translation. Two identical disks were placed on opposite corners of an invisible square, with another pair arranged similarly on a larger concentric square. Participants tracked one designated disk from each pair as they rotated or translated. Performance was significantly worse for rotation. A second experiment showed that visible lines connecting paired disks impaired translational tracking, demonstrating that composite representations can be induced both by visible connections and by the yoking inherent to rotation. Three additional experiments replicated these findings and revealed increased error rates on trials which demanded greater reexpression of relational variables. A sixth experiment extended the reasoning to the freezing illusion, introducing a novel method to quantify illusion strength. Rotation produced a stronger illusion than matched translation. Our findings indicate that principles of object-centered representation apply broadly in visual perception, including axes and relational variables not physically present in the stimulus. (PsycInfo Database Record (c) 2026 APA, all rights reserved).
Wu et al. (Mon,) studied this question.