期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：26
页码：8142-8147
DOI：10.1073/pnas.1500361112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceIn our visual environment, object motion is strongly correlated with changes in object position. However, there is no unifying computational framework that can account for both motion and position perception and their interactions. Here, we propose and test an object-tracking model that optimally integrates sensory signals with a realistic model of motion dynamics. The model accounts for several well-known visual illusions, including motion-induced position shifts, slow speed biases, and the curveball illusion. Moreover, the model also makes several novel and, in some cases, counterintuitive predictions about interdependencies between position and motion. In summary, we provide a unifying framework that reconceptualizes how the human visual system constructs coherent percepts from noisy position and motion signals. Despite growing evidence for perceptual interactions between motion and position, no unifying framework exists to account for these two key features of our visual experience. We show that percepts of both object position and motion derive from a common object-tracking system--a system that optimally integrates sensory signals with a realistic model of motion dynamics, effectively inferring their generative causes. The object-tracking model provides an excellent fit to both position and motion judgments in simple stimuli. With no changes in model parameters, the same model also accounts for subjects' novel illusory percepts in more complex moving stimuli. The resulting framework is characterized by a strong bidirectional coupling between position and motion estimates and provides a rational, unifying account of a number of motion and position phenomena that are currently thought to arise from independent mechanisms. This includes motion-induced shifts in perceived position, perceptual slow-speed biases, slowing of motions shown in visual periphery, and the well-known curveball illusion. These results reveal that motion perception cannot be isolated from position signals. Even in the simplest displays with no changes in object position, our perception is driven by the output of an object-tracking system that rationally infers different generative causes of motion signals. Taken together, we show that object tracking plays a fundamental role in perception of visual motion and position.
