Do discreteness and rivalry coexist in illusory motion reversals?

Rojas, Daniel; Carmona‐Fontaine, Carlos; López-Calderón, Javier; Aboitiz, Francisco

doi:10.1016/j.visres.2005.07.023

Cited by 6 publications

(5 citation statements)

References 10 publications

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“…However, these findings did not rule out the possibility that regions of the visual field are sampled independently, perhaps in an object-based manner (VanRullen, 2006). Given this uncertainty, several authors remain advocates of the snapshot hypothesis (Andrews & Purves, 2005;Rojas, Carmona-Fontaine, Lopez-Calderón, & Aboitiz, 2006;Simpson, Shahani, & Manahilov, 2005;VanRullen, 2006VanRullen, , 2007VanRullen et al, 2005).…”

Section: Introductionmentioning

confidence: 98%

Evidence against the temporal subsampling account of illusory motion reversal

Kline

Eagleman

2008

Journal of Vision

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An illusion of reversed motion may occur sporadically while viewing continuous smooth motion. This has been suggested as evidence of discrete temporal sampling by the visual system in analogy to the sampling that generates the wagon-wheel effect on film (D. Purves, J. A. Paydarfar, & T. J. Andrews, 1996; R. VanRullen, L. Reddy, & C. Koch, 2005). In an alternative theory, the illusion is not the result of discrete sampling but instead of perceptual rivalry between appropriately activated and spuriously activated motion detectors (K. A. Kline, A. O. Holcombe, & D. M. Eagleman, 2004, 2006). Results of the current study demonstrate that illusory reversals of two spatially overlapping and orthogonal motions often occur separately, providing evidence against the possibility that illusory motion reversal (IMR) is caused by temporal sampling within a visual region. Further, we find that IMR occurs with non-uniform and non-periodic stimuli-an observation that is not accounted for by the temporal sampling hypothesis. We propose, that a motion aftereffect is superimposed on the moving stimulus, sporadically allowing motion detectors for the reverse direction to dominate perception.

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Section: Introductionmentioning

confidence: 98%

Evidence against the temporal subsampling account of illusory motion reversal

Kline

Eagleman

2008

Journal of Vision

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“…Such aliasing occurs when the wheel rotates at a slightly slower temporal frequency than the sampling rate of the camera recording it, since with each frame the wheel's spokes appear to have rotated backward a small amount rather than forward by a large amount. Surprisingly, a similar illusion can occur when periodic moving objects in the real world are viewed under continuous lighting conditions, such as sunlight (Kline, Holcombe, & Eagleman, 2004;Purves, Paydarfar, & Andrews, 1996;Schouten, 1967;Simpson, Shahani, & Manahilov, 2005;VanRullen, Reddy, & Koch, 2005), leading many to suggest that motion perception may involve discrete sampling of visual information, like a movie camera (Andrews & Purves, 2005;Crick & Koch, 2003;Koch, 2004;McComas & Cupido, 1999;Purves et al, 1996;Rojas, Carmona-Fontaine, López-Calderón, & Aboitiz, 2006;Simpson et al, 2005;VanRullen & Koch, 2003;VanRullen et al, 2005). Specifically, it has been proposed that such discrete sampling originates in the attentional system (Reddy, Rémy, Vayssière, & VanRullen, 2011;VanRullen, Pascual-Leone, & Battelli, 2008;VanRullen et al, 2005;VanRullen, Reddy, & Koch, 2006;VanRullen, 2006VanRullen, , 2007, since this continuous wagon wheel illusion (c-WWI) is strongly associated with attention: It occurs far less frequently when attention is drawn away from the periodic stimulus by a concurrent demanding discrimination task (VanRullen et al, 2005); it does not occur in the entire visual field (Kline et al, 2004) but, rather, in one object at a time that may be formed from several elements according to gestalt principles of association (VanRullen, 2006); and it has been associated with right parietal lobe processing with a variety of neurophysiological techniques (EEG, VanRullen et al, 2006;r-TMS, VanRullen et al, 2008;fMRI, Reddy et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Attentional sampling of multiple wagon wheels

Macdonald

Cavanagh

VanRullen

2013

Atten Percept Psychophys

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Attending to a periodic motion stimulus can induce illusory reversals of the direction of motion. This continuous wagon wheel illusion (c-WWI) has been taken to reflect discrete sampling of motion information by visual attention. An alternative view is that it is caused by adaptation. Here, we attempt to discriminate between these two interpretations by asking participants to attend to multiple periodic motion stimuli: The discrete attentional sampling account, but not the adaptation account, predicts a decrease of c-WWI temporalfrequency tuning with set size (with a single periodic motion stimulus the c-WWI is tuned to a temporal frequency of 10 Hz). We presented one to four rotating gratings that occasionally reversed direction while participants counted reversals. We considered reversal overestimations as manifestations of the c-WWI and determined the temporal-frequency tuning of the illusion for each set size. Optimal temporal frequency decreased with increasing set size. This outcome favors the discrete attentional sampling interpretation of the c-WWI, with a sampling rate for each individual stimulus dependent on the number of stimuli attended.

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“…Recently there has been mounting evidence in favor of the high-level discrete sampling account-even though this is still heavily debated Holcombe and Seizova-Cajic, 2008;Holcombe et al, 2005;Kline and Eagleman, 2008;Kline et al, 2004Kline et al, , 2006Rojas et al, 2006]. The c-WWI has been shown to depend on attentional and object-based mechanisms [VanRullen, 2006;VanRullen et al, 2005] and can occur for both first order (luminance defined) and second order (contrast defined) motion stimuli .…”

Section: Introductionmentioning

confidence: 99%

Neural correlates of the continuous Wagon Wheel Illusion: A functional MRI study

Reddy¹,

Rémy²,

Vayssière³

et al. 2011

Human Brain Mapping

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After prolonged viewing of a continuous periodic motion stimulus at frequencies around 10 Hz, observers experience a fleeting impression of reversed motion: the continuous Wagon Wheel Illusion (c-WWI). To account for this phenomenon it has been proposed that attentional mechanisms discretely sample motion information. Alternative accounts argue that the illusion relies on the spurious activation of motion detectors, which under the effect of adaptation could trigger a reversed percept. We investigated the neural correlates of the c-WWI using fMRI (3T). Subjects viewed a vertically bisected ring containing a radial grating unambiguously rotating at 10 Hz; they continuously reported the perceived motion direction within each half of the ring. The two halves always rotated in opposite directions, allowing us to separately explore illusory reversals occurring within each hemifield. Comparing BOLD activity during illusory (c-WWI) or real perceptual periods revealed systematic differences in right parietal regions, in addition to the right motion complex MT+. This activation pattern did not depend on the side on which the illusion occurred, and could not be accounted for by purely perceptual switch-related activity-known to encompass parietal regions during other bistable effects. This first characterization of the fMRI correlates of the c-WWI may have implications for the different theoretical explanations of the phenomenon.

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Do discreteness and rivalry coexist in illusory motion reversals?

Cited by 6 publications

References 10 publications

Evidence against the temporal subsampling account of illusory motion reversal

Evidence against the temporal subsampling account of illusory motion reversal

Attentional sampling of multiple wagon wheels

Neural correlates of the continuous Wagon Wheel Illusion: A functional MRI study

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