The absolute disparity anomaly and the mechanism of relative disparities

Chopin, Adrien; Levi, Dennis M.; Knill, David C.; Bavelier, Daphné

doi:10.1167/16.8.2

Cited by 19 publications

(23 citation statements)

References 54 publications

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“…The additional spheres were arranged in form of three rings (each constituted by 12 spheres) around the central target, with a radius of 18, 27, and 36 cm, respectively ( Figure 1 ). In general, relative depth information has been discussed to be an important source for depth perception (Neri et al, 2004; Chopin et al, 2016). Within a virtual 3D setting relative depth information has also been shown to be a prerequisite to detect RT effects (Plewan and Rinkenauer, 2016).…”

Section: Methodsmentioning

confidence: 99%

Fast and Forceful: Modulation of Response Activation Induced by Shifts of Perceived Depth in Virtual 3D Space

Plewan

Rinkenauer

2016

Front. Psychol.

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Reaction time (RT) can strongly be influenced by a number of stimulus properties. For instance, there was converging evidence that perceived size rather than physical (i.e., retinal) size constitutes a major determinant of RT. However, this view has recently been challenged since within a virtual three-dimensional (3D) environment retinal size modulation failed to influence RT. In order to further investigate this issue in the present experiments response force (RF) was recorded as a supplemental measure of response activation in simple reaction tasks. In two separate experiments participants’ task was to react as fast as possible to the occurrence of a target located close to the observer or farther away while the offset between target locations was increased from Experiment 1 to Experiment 2. At the same time perceived target size (by varying the retinal size across depth planes) and target type (sphere vs. soccer ball) were modulated. Both experiments revealed faster and more forceful reactions when targets were presented closer to the observers. Perceived size and target type barely affected RT and RF in Experiment 1 but differentially affected both variables in Experiment 2. Thus, the present findings emphasize the usefulness of RF as a supplement to conventional RT measurement. On a behavioral level the results confirm that (at least) within virtual 3D space perceived object size neither strongly influences RT nor RF. Rather the relative position within egocentric (body-centered) space presumably indicates an object’s behavioral relevance and consequently constitutes an important modulator of visual processing.

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Section: Methodsmentioning

confidence: 99%

Fast and Forceful: Modulation of Response Activation Induced by Shifts of Perceived Depth in Virtual 3D Space

Plewan

Rinkenauer

2016

Front. Psychol.

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“…Relative disparity is the difference between the absolute disparities of two objects. There is converging evidence that relative disparities are calculated from absolute disparities and that the two systems are therefore not independent . However, conscious depth perception shows little or no direct access to absolute disparities (the absolute disparity anomaly).…”

Section: How To Measure Stereoacuity For Determining Stereoblindness?mentioning

confidence: 99%

“…There is converging evidence that relative disparities are calculated from absolute disparities and that the two systems are therefore not independent . However, conscious depth perception shows little or no direct access to absolute disparities (the absolute disparity anomaly). Some brain‐damaged patients can also show large impairments of stereopsis from relative disparities while still be able to normally (but poorly) access absolute disparities .…”

Section: How To Measure Stereoacuity For Determining Stereoblindness?mentioning

confidence: 99%

“…The larger the distance between two items, the more the visual system relies on delta‐vergence than on instantaneous stereopsis . Observers unable to use instantaneous stereopsis may still be able to use delta‐vergence (and vice versa) because vergence can rely on absolute disparities while those disparities are inaccessible to other visual modules . Therefore, the ideal stereoblindness test would allow delta‐vergence thanks to long presentations and either large disparities or a stimulus spanning a large visual field.…”

Section: How To Measure Stereoacuity For Determining Stereoblindness?mentioning

confidence: 99%

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The prevalence and diagnosis of ‘stereoblindness’ in adults less than 60 years of age: a best evidence synthesis

Chopin

Bavelier

Levi

2019

Ophthalmic Physiologic Optic

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Purpose: Stereoscopic vision (or stereopsis) is the ability to perceive depth from binocular disparity -the difference of viewpoints between the two eyes. Interestingly, there are large individual differences as to how well one can appreciate depth from such a cue. The total absence of stereoscopic vision, called 'stereoblindness', has been associated with negative behavioural outcomes such as poor distance estimation. Surprisingly, the prevalence of stereoblindness remains unclear, as it appears highly dependent on the way in which stereopsis is measured. Recent findings: This review highlights the fact that stereopsis is not a unitary construct, but rather implies different systems. The optimal conditions for measuring these varieties of stereoscopic information processing are discussed given the goal of detecting stereoblindness, using either psychophysical or clinical stereotests. In that light, we then discuss the estimates of stereoblindness prevalence of past studies. Summary: We identify four different approaches that all converge toward a prevalence of stereoblindness of 7% (median approach: 7%; unambiguous-stereoblindness-criteria approach: 7%; visual-defect-included approach: 7%; multiple-criteria approach: 7%). We note that these estimates were derived considering adults of age <60 years old. Older adults may have a higher prevalence. Finally, we make recommendations for a new ecological definition of stereoblindness and for efficient clinical methods for determining stereoblindness by adapting existing tools. 66Ophthalmic and Physiological Optics ISSN 0275-5408 Convergent vs divergent disparity systemsThere is an ongoing debate between two views on the processing of convergent (or crossed/near) and divergent (or uncrossed/far) disparities. According to the first view, each

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“…Slant from HSR is defined by a smooth disparity gradient. It has been found that slant is processed more accurately (Brookes & Stevens, 1989 ; Stevens & Brookes, 1988 ; van Ee et al, 1999 ; van Ee & Erkelens, 1995 ) and faster (Gillam, Chambers, & Russo, 1988 ; Gillam et al, 1984 ; van Ee & Erkelens, 1996 ) when a reference frame is provided, because across short distances within the visual field, relative disparity is measured very robustly (Backus & Matza-Brown, 2003 ; Blakemore, 1970 ; Chopin, Levi, Knill, & Bavelier, 2016 ).…”

Section: Experiments 4: Slant Contrastmentioning

confidence: 99%

Early dynamics of stereoscopic surface slant perception

2017

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Surface orientation is an important visual primitive that can be estimated from monocular or binocular (stereoscopic) signals. Changes in motor planning occur within about 200 ms after either type of signal is perturbed, but the time it takes for apparent (perceived) slant to develop from stereoscopic cues is not known. Apparent slant sometimes develops very slowly (Gillam, Chambers, & Russo, 1988; van Ee & Erkelens, 1996). However, these long durations could reflect the time it takes for the visual system to resolve conflicts between slant cues that inevitably specify different slants in laboratory displays (Allison & Howard, 2000). We used a speed–accuracy tradeoff analysis to measure the time it takes to discriminate slant, allowing us to report psychometric functions as a function of response time. Observers reported which side of a slanted surface was farther, with a temporal deadline for responding that varied block-to-block. Stereoscopic slant discrimination rose above chance starting at 200 ms after stimulus onset. Unexpectedly, observers discriminated slant from binocular disparity faster than texture, and for stereoscopic whole-field stimuli faster than stereoscopic slant contrast stimuli. However, performance after the initial deviation from chance increased more rapidly for slant-contrast stimuli than whole-field stimuli. Discrimination latencies were similar for slants about the horizontal and vertical axes, but performance increased faster for slants about the vertical axis. Finally, slant from vertical disparity was somewhat slower than slant from horizontal disparity, which may reflect cue conflict. These results demonstrate, in contradiction with the previous literature, that the perception of slant from disparity happens very quickly—in fact, more quickly than the perception of slant from texture—and in comparable time to the simple perception of brightness from luminance.

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The absolute disparity anomaly and the mechanism of relative disparities

Cited by 19 publications

References 54 publications

Fast and Forceful: Modulation of Response Activation Induced by Shifts of Perceived Depth in Virtual 3D Space

Fast and Forceful: Modulation of Response Activation Induced by Shifts of Perceived Depth in Virtual 3D Space

The prevalence and diagnosis of ‘stereoblindness’ in adults less than 60 years of age: a best evidence synthesis

Early dynamics of stereoscopic surface slant perception

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