September 2021
Volume 21, Issue 9
Open Access
Vision Sciences Society Annual Meeting Abstract  |   September 2021
The Orbiting Circles Illusion: Induced changes in the length and direction of motion trajectory
Author Affiliations & Notes
  • Ryan Mruczek
    College of the Holy Cross
  • Gideon Caplovitz
    University of Nevada, Reno
  • Footnotes
    Acknowledgements  NSF 1632738; NSF 1632849; Robert L. Ardizzone Fund for Tenure Track Excellence
Journal of Vision September 2021, Vol.21, 2330. doi:
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      Ryan Mruczek, Gideon Caplovitz; The Orbiting Circles Illusion: Induced changes in the length and direction of motion trajectory. Journal of Vision 2021;21(9):2330.

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      © ARVO (1962-2015); The Authors (2016-present)

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We introduce a novel motion illusion that we call the Orbiting Circles Illusion. The illusion uses relative motion cues to induce changes in the perceived trajectory of a continuously moving object. A central target circle continuously moves along a circular path in an apparent orbit around a central point. Concurrently, a set of inducers (similar to those in the Ebbinghaus configuration) surround the central target circle, each moving along their own local orbits. Perceptually, the relative motion of the inducers alters the apparent trajectory of the central circle. The specific perception depends on the speed and position of the inducers relative to the target. The illusion is apparent under peripheral fixation conditions, suggesting that small eye movements are not necessary to alter the perceived position of the target. A central fixation point or a static object near the target abolishes the illusion. Overall, the illusion shares many similarities with frame-induced position shifts (Cavanagh, Wexler, & Anstis, 2020, Journal of Vision, 20(11), 607-607). Additionally, it reveals two striking effects. First, the circular motion of the target can appear strictly linear in nature. Second, the length of the linear trajectory can appear much greater than the physical displacement of the target. The former effect has implications for the coding of curvature on motion trajectories and the latter effect has implications for the coding of position that have been recently studied using paradigms such as the flash drag, flash lag, and double-drift. Here, we demonstrate a number of factors, such as speed, positioning, and feature similarity, that affect the magnitude of the Orbiting Circles Illusion.


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