VanRullen, Rufin and Reddy, Leila and Koch, Christof (2005) Attention-driven discrete sampling of motion perception. Proceedings of the National Academy of Sciences of the United States of America, 102 (14). pp. 5291-5296. ISSN 0027-8424 http://resolver.caltech.edu/CaltechAUTHORS:VANpnas05
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In movies or on TV, a wheel can seem to rotate backwards, due to the temporal subsampling inherent in the recording process (the wagon wheel illusion). Surprisingly, this effect has also been reported under continuous light, suggesting that our visual system, too, might sample motion in discrete "snapshots." Recently, these results and their interpretation have been challenged. Here, we investigate the continuous wagon wheel illusion as a form of bistable percept. We observe a strong temporal frequency dependence: the illusion is maximal at alternation rates around 10 Hz but shows no spatial frequency dependence. We introduce an objective method, based on unbalanced counterphase gratings, for measuring this phenomenon and demonstrate that the effect critically depends on attention: the continuous wagon wheel illusion was almost abolished in the absence of focused attention. A motion-energy model, coupled with attention-dependent temporal subsampling of the perceptual stream at rates between 10 and 20 Hz, can quantitatively account for the observed data.
|Additional Information:||Copyright © 2005 by the National Academy of Sciences. Edited by Dale Purves, Duke University Medical Center, Durham, NC, and approved February 23, 2005 (received for review December 9, 2004). This paper was submitted directly (Track II) to the PNAS office. The work was greatly inspired and enriched by ideas from the late Francis Crick. We thank Caitlin Berry for substantial help with pilot studies. This research was supported by the Centre National de la Recherche Scientifique, the National Science Foundation Engineering Research Center, the W. M. Keck Foundation Fund, the Gordon More Foundation, and the Swartz Foundation for Computational Neuroscience.|
|Subject Keywords:||wagon-wheel illusion, 2nd-order motion, human-vision, visual-attention, modulation, mechanisms, stimuli, alpha, oscillations, performance|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||17 Nov 2005|
|Last Modified:||26 Dec 2012 08:42|
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