Contribution of bottom-up and top-down motion processes to perceived position.

Whitney, David

doi:10.1037/0096-1523.32.6.1380

Cited by 20 publications

(27 citation statements)

References 113 publications

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“…To determine whether the motion-energy signals evoked by the Plunger stimuli were being pooled, we exploited the ''motion drag'' effect, in which the perceived position of peripherally-presented objects is spatially displaced in the direction of motion (Scarfe & Johnston, 2010;Whitney, 2006;Whitney & Cavanagh, 2000;Whitney et al, 2003). To do this, we first established that the global TAM array induced motion drag.…”

Section: Resultsmentioning

confidence: 99%

The shape of motion perception: Global pooling of transformational apparent motion

et al. 2013

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Transformational apparent motion (TAM) is a visual phenomenon highlighting the utility of form information in motion processing. In TAM, smooth apparent motion is perceived when shapes in certain spatiotemporal arrangements change. It has been argued that TAM relies on a separate high-level form-motion system. Few studies have, however, systematically examined how TAM relates to conventional low-level motion-energy systems. To this end, we report a series of experiments showing that, like conventional motion stimuli, multiple TAM signals can combine into a global motion percept. We show that, contrary to previous claims, TAM does not require selective attention, and instead, multiple TAM signals can be simultaneously combined with coherence thresholds reflecting integration across the entire stimulus area. This system is relatively weak, less tolerant to noise, and easily overridden when motion energy cues are sufficiently strong. We conclude that TAM arises from high-level form-motion information that enters the motion system by, at least, the stage of global motion pooling.

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Section: Resultsmentioning

confidence: 99%

The shape of motion perception: Global pooling of transformational apparent motion

et al. 2013

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“…The displacement of the flash was greatest when it was aligned in time and location with the physical trajectory endpoint. Nevertheless, there was a shift in the perceived position of the flash that remained at about 1/10 th the maximum even when it was presented off the moving texture rather than on it (e.g., as in the flash drag stimulus, Whitney & Cavanagh, 2000a; Durant & Johnston, 2004; Roach & McGraw, 2006; Shim & Cavanagh, 2005; Whitney, 2006), or at the midpoint of the trajectory rather than at the reversal point, or out of alignment with the local contrast edges in the moving trajectory, rather than in alignment.…”

Section: Experiments 4: Is Attention Required?mentioning

confidence: 99%

“…Specifically, the flash grab effect requires attention (Figure 15) whereas the flash drag can be seen with or without attention. In particular, the flash drag is seen with attentive tracking (Shim & Cavanagh, 2005) and transformational apparent motion (Whitney, 2006) where there is no low-level motion signal. It is also seen for motion that cannot be tracked attentively either because it is too fast (Whitney & Cavanagh, 2000a) or because it is reversing too rapidly and unpredictably (Fugiake et al, 2011).…”

Section: Experiments 4: Is Attention Required?mentioning

confidence: 99%

The flash grab effect

2013

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When an object moves back and forth, its trajectory appears significantly shorter than it actually is. The object appears to stop and reverse well before its actual reversal point, as if there is some averaging of location within a window of about 100 ms (Sinico et al, 2009). Surprisingly, if a bar is flashed at the physical end point of the trajectory, right on top of the object, just as it reverses direction, the flash is also shifted – grabbed by the object – and is seen at the perceived endpoint of the trajectory rather than the physical endpoint. This can shift the perceived location of the flash by as much as 2 or 3 times its physical size and by up to several degrees of visual angle. We first show that the position shift of the flash is generated by the trajectory shortening, as the same shift is seen with or without the flash. The flash itself is only grabbed if it is presented within a small spatiotemporal attraction zone around the physical end point of the trajectory. Any flash falling in that zone is pulled toward the perceived endpoint. The effect scales linearly with speed, up to a maximum, and is independent of the contrast of the moving stimulus once it is above 5%. Finally, we demonstrate that this position shift requires attention. These results reveal a new “flash grab” effect in the family of motion-induced position shifts. Although it most resembles the flash drag effect, it differs from this in the following ways: 1) it has a different temporal profile, 2) it requires attention, 3) it is about 10 times larger.

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“…Subsequently, several papers have found evidence for a contribution from the high-level motion system to this position shift illusion in the absence of low-level motion energy. These studies used either motion viewed through apertures (Watanabe, Nijhawan, & Shimojo, 2002), inferred motion (Watanabe, Sato, & Shimojo, 2003), or apparent motion (Shim & Cavanagh, 2004; Whitney, 2006). Other studies have demonstrated the position shift for stimuli that could only drive the low-level motion system (Harp, Bressler, & Whitney, 2007; Whitney, 2005).…”

Section: Introductionmentioning

confidence: 99%

Voluntary attention modulates motion-induced mislocalization

Tse¹,

Whitney²,

Anstis³

et al. 2011

Journal of Vision

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When a test is flashed on top of two superimposed, opposing motions, the perceived location of the test is shifted in opposite directions depending on which of the two motions is attended. Because the stimulus remains unchanged as attention switches from one motion to the other, the effect cannot be due to stimulus-driven, low-level motion. A control condition ruled out any contribution from possible attention-induced cyclotorsion of the eyes. This provides the strongest evidence to date for a role of attention in the perception of location, and establishes that what we attend to influences where we perceive objects to be.

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Contribution of bottom-up and top-down motion processes to perceived position.

Cited by 20 publications

References 113 publications

The shape of motion perception: Global pooling of transformational apparent motion

The shape of motion perception: Global pooling of transformational apparent motion

The flash grab effect

Voluntary attention modulates motion-induced mislocalization

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