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Remy Allard, Angelo Arleo; Position-based vs energy-based motion processing. Journal of Vision 2016;16(12):670. doi: 10.1167/16.12.670.
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© 2017 Association for Research in Vision and Ophthalmology.
It is generally presumed that the perceived motion direction of an object is based on some integration of local motion signals extracted from energy-based motion detectors. However, objects are often perceived as moving in their veridical direction even when the direction of the mean local motion signal diverges from the veridical motion direction. Such percepts have been taken as evidence of complex motion integration of local motion signals to compute the veridical motion direction of objects. An alternative hypothesis is that the perceived direction of a moving object is not based on local motion signals at all, but rather based on tracking the position of the object. We evaluated the perceived motion direction of objects when the direction of the mean local motion signal diverged from the veridical motion direction (reverse-phi, furrow illusion and other stimuli). Energy-based processing of local motion signals and position-based tracking of the objects were each neutralized (or not) by manipulating inter-stimuli intervals (Smith, 1994) and crowding (Allard & Faubert, 2013), respectively. When both motion systems were neutralized, no motion direction was perceived. When only position-based tracking was neutralized, motion was perceived in the direction of the mean local motion signal, which suggests a simple integration (i.e., averaging) of local motion signals. When position-based tracking was not neutralized, objects were perceived as moving in their veridical direction whether energy-based motion processing was neutralized or not, which suggests that the perceived motion direction was determined by position-based tracking. We conclude that when position-based tracking of objects can operate efficiently, this strategy dominates and motion perception is not based on some integration of local (energy-based) motion signals. There is no need for complex integration of local motion signals to compute the veridical motion direction of objects.
Meeting abstract presented at VSS 2016
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