Stopping the motion and sleuthing the flash-lag effect: spatial uncertainty is the key to perceptual mislocalization

Kanai, Ryota; Sheth, Bhavin R.; Shimojo, Shinsuke

doi:10.1016/j.visres.2003.10.028

Cited by 105 publications

(122 citation statements)

References 49 publications

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“…However, in this experiment we did not find a total elimination of the flash-lag effect; a small but significant forward displacement for blanks of 120 ms was still measured. This effect is likely due to the fact that observers did not foveate the position of the flash, a finding that is consistent with Kanai et al (2004), who reported a flash-lag in the flash-terminated condition for peripherally presented stimuli. In previous pilot studies, where stimuli were presented foveally and the separation between the moving object and the flashes was smaller, observers actually achieved close to perfect localization performance, that is, a total elimination of the flash-lag effect (data not presented).…”

Section: Discussionsupporting

confidence: 82%

Going, going, gone: Localizing abrupt offsets of moving objects.

Maus¹,

Nijhawan²

2009

Journal of Experimental Psychology: Human Perception and Perfor

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When a moving object abruptly disappears, this profoundly influences its localization by the visual system. In Experiment 1, 2 aligned objects moved across the screen, and 1 of them abruptly disappeared. Observers reported seeing the objects misaligned at the time of the offset, with the continuing object leading. Experiment 2 showed that the perceived forward displacement of the moving object depended on speed and that offsets were localized accurately. Two competing representations of position for moving objects are proposed: 1 based on a spatially extrapolated internal model, and the other based on transient signals elicited by sudden changes in the object trajectory that can correct the forward-shifted position. Experiment 3 measured forward displacements for moving objects that disappeared only for a short time or abruptly reduced contrast by various amounts. Manipulating the relative strength of the 2 position representations in this way resulted in intermediate positions being perceived, with weaker motion signals or stronger transients leading to less forward displacement. This 2-process mechanism is advantageous because it uses available information about object position to maximally reduce spatiotemporal localization errors.Keywords: flash-lag effect, backward masking, visual transients, motion extrapolation, moving objects Supplemental materials: http://dx.doi.org/10.1037/a0012317.suppIn the flash-lag effect, a moving object appears to be ahead of a spatially aligned flashed object. This finding has sparked a debate about how the nervous system processes moving objects and determines their perceived position. This is an important problem as neural delays in the retina and the central vision pathway are liable to lead to spatial localization errors. One hypothesis, termed motion extrapolation, states that moving objects are spatially shifted forward to counteract the influence of neural delays in the visual pathways on the perceived position of moving objects (Nijhawan, 1994). If one assumes that perceptual awareness of the position of an object requires cortical activity, then a delay in the pathway from the photoreceptors to the primary visual cortex of about 80 ms (Schmolesky et al, 1998) would imply that moving objects are always perceived to lag their "true" position by the distance they moved in that time. However, by analyzing the speed and direction of a moving object, the visual system could extrapolate its position forward by an appropriate amount and so compensate for these processing delays. In the flash-lag effect, this forward shift is apparent, because the flash does not undergo an equivalent spatial shift, thereby resulting in a perceived gap between the moving object and the flash, although they are physically aligned.Several alternative accounts have been brought forward to explain the findings of the flash-lag effect, amongst them differential attentional deployment

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Section: Discussionsupporting

confidence: 82%

Going, going, gone: Localizing abrupt offsets of moving objects.

Maus¹,

Nijhawan²

2009

Journal of Experimental Psychology: Human Perception and Perfor

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“…Conceptually similar models have been proposed by previous investigators to explain related phenomena in retina (Berry et al, 1999), thalamus (Sillito et al, 1994), primary visual cortex (Jancke et al, 1999;Fu et al, 2004), extrastriate cortex (Mikami, 1992;Sundberg et al, 2006), and behavior (McKee and Welch, 1985;Verghese et al, 1999); although implementation details differ, these computational schemes share the underlying notion of what has been termed "asymmetric spread" (Kanai et al, 2004), "priming" (Sheth et al, 2000), "feedforward wave" (Baldo and Caticha, 2005), or "sequential recruitment" (McKee and Welch, 1985). There is overall consensus that this progressive activation of the motion-sensitive circuit, which may be interpreted as a rudimentary extrapolation mechanism (Baldo and Caticha, 2005) or locking/focusing device (Sillito et al, 1994), may be connected to a class of anticipatory perceptual phenomena.…”

Section: Self-reinforcing Feedback Modelmentioning

confidence: 56%

Dynamic Engagement of Human Motion Detectors across Space-Time Coordinates

Neri

2014

Journal of Neuroscience

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Motion detection is a fundamental property of the visual system. The gold standard for studying and understanding this function is the motion energy model. This computational tool relies on spatiotemporally selective filters that capture the change in spatial position over time afforded by moving objects. Although the filters are defined in space-time, their human counterparts have never been studied in their native spatiotemporal space but rather in the corresponding frequency domain. When this frequency description is back-projected to spatiotemporal description, not all characteristics of the underlying process are retained, leaving open the possibility that important properties of human motion detection may have remained unexplored. We derived descriptors of motion detectors in native space-time, and discovered a large unexpected dynamic structure involving a Ͼ2ϫ change in detector amplitude over the first ϳ100 ms. This property is not predicted by the energy model, generalizes across the visual field, and is robust to adaptation; however, it is silenced by surround inhibition and is contrast dependent. We account for all results by extending the motion energy model to incorporate a small network that supports feedforward spread of activation along the motion trajectory via a simple gain-control circuit.

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“…Previous studies by Fu et al (2001) and Kanai et al (2006) demonstrated that the extrapolation of visual targets farther in the direction of motion was larger for spatially blurred targets-that is, for targets with a high degree of position uncertainty. Our results at paralateral spatial locations are in accord with these earlier findings and confirm that position uncertainty due to less precise encoding of spatial coordinates leads to larger forward displacements.…”

Section: Discussionmentioning

confidence: 95%

“…Previous studies in which position uncertainty was induced either by the blurring of target intensity and contrast (Fu, Shen, & Dan, 2001) or by peripheral stimulus presentation (Kanai, Sheth, & Shimojo, 2006) have shown that less accurate positional information results in larger forward displacements. On the basis of the latter findings, we hypothesized that less precise encoding of spatial coordinates in paralateral and lateral space leads to greater position uncertainty and should be reflected in an increase in the magnitude of forward displacement.…”

mentioning

confidence: 99%

A comparison of visual and auditory representational momentum in spatial tasks

Schmiedchen

Freigang

Rübsamen

et al. 2013

Atten Percept Psychophys

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Similarities have been observed in the localization of the final position of moving visual and moving auditory stimuli: Perceived endpoints that are judged to be farther in the direction of motion in both modalities likely reflect extrapolation of the trajectory, mediated by predictive mechanisms at higher cognitive levels. However, actual comparisons of the magnitudes of displacement between visual tasks and auditory tasks using the same experimental setup are rare. As such, the purpose of the present free-field study was to investigate the influences of the spatial location of motion offset, stimulus velocity, and motion direction on the localization of the final positions of moving auditory stimuli (Experiment 1 and 2) and moving visual stimuli (Experiment 3). To assess whether auditory performance is affected by dynamically changing binaural cues that are used for the localization of moving auditory stimuli (interaural time differences for low-frequency sounds and interaural intensity differences for high-frequency sounds), two distinct noise bands were employed in Experiments 1 and 2. In all three experiments, less precise encoding of spatial coordinates in paralateral space resulted in larger forward displacements, but this effect was drowned out by the underestimation of target eccentricity in the extreme periphery. Furthermore, our results revealed clear differences between visual and auditory tasks. Displacements in the visual task were dependent on velocity and the spatial location of the final position, but an additional influence of motion direction was observed in the auditory tasks. Together, these findings indicate that the modalityspecific processing of motion parameters affects the extrapolation of the trajectory.

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Stopping the motion and sleuthing the flash-lag effect: spatial uncertainty is the key to perceptual mislocalization

Cited by 105 publications

References 49 publications

Going, going, gone: Localizing abrupt offsets of moving objects.

Going, going, gone: Localizing abrupt offsets of moving objects.

Dynamic Engagement of Human Motion Detectors across Space-Time Coordinates

A comparison of visual and auditory representational momentum in spatial tasks

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