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Kevin Hartstein, Peter Tse; First and second order transformational apparent motion have similar temporal dynamics. Journal of Vision 2016;16(12):660. doi: 10.1167/16.12.660.
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© ARVO (1962-2015); The Authors (2016-present)
Introduction: Transformational apparent motion (TAM) occurs when one figure is replaced with another that overlaps the first in location, and is perceived as a shape change of the original object (Tse, Cavanagh, & Nakayama, 1998). This property reveals the importance of high-level figural processing constraints on motion perception that cannot be observed in standard apparent motion (Tse & Logothetis, 2002). Here, we seek to determine whether this figural processing effect persists in the absence of luminance-defined figures. Methods and Results: Our experiment compared the temporal characteristics of TAM for luminance-defined objects (black stimuli on a uniform gray background, first-order TAM) and texture-defined objects (white noise stimuli on a white noise background, second-order TAM). While maintaining fixation, participants viewed a TAM display consisting of two horizontally aligned squares in the lower visual field. At variable stimulus onset asynchronies, a rectangle appeared connecting the squares. At the same time, a cue-square appeared on top of one of the original stimuli, biasing the direction of perceived motion in the central rectangle toward that side. Participants indicated whether they perceived motion to the left, to the right, or no motion. Both first and second order TAM caused a compelling percept of motion in the cued direction (88.50% of trials in first-order, 77.65% in second-order). Although the figural information in second-order TAM is transient and relatively weak, the time course of second-order TAM was nearly identical to that of first-order TAM (see supplementary materials). This result suggests that even weak figural cues in the absence of luminance changes or first-order motion cues can strongly affect the perceptual interpretation of ambiguous motion. Conclusion: Here we show that weakly defined figures with no luminance differences guide motion perception with a time course similar to luminance-defined figural changes, emphasizing the importance of figural processing in motion perception.
Meeting abstract presented at VSS 2016
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