Ambiguous chromatic neural representations: perceptual resolution by grouping

Shevell, Steven K.

doi:10.1016/j.cobeha.2019.10.010

Cited by 3 publications

(4 citation statements)

References 35 publications

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“…Grouping was assessed using the proportion of time that all discs, ambiguous or unambiguous, were simultaneously perceived as the same color. Multiple separate retinotopic areas with ambiguous chromatic representations are known to resolve together perceptually to all appear the same color more often than chance ( Slezak & Shevell, 2018 ; Shevell, 2019 ). Experiment 1 tested how unambiguous color percepts affected the perceptual resolution of the ambiguous ones by comparing the dominance time of perceiving as identical ambiguous stimuli presented alone versus ambiguous and unambiguous stimuli presented simultaneously.…”

Section: Resultsmentioning

confidence: 99%

“…In fact, this occurs with multiple simultaneous and identical ambiguous representations: All objects often are seen as the same color even though their appearance varies over time—in this case, from all red to all green. Thus, perceptual resolution of multiple ambiguous neural representations leads to seeing all of them as identical far more than if each representation is resolved independently ( Kovács, Papathomas, Yang & Fehér, 1996 ; Dobbins & Grossman, 2018 ; Shevell, 2019 ).…”

Section: Introductionmentioning

confidence: 99%

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Ambiguity is a linking feature for interocular grouping

2022

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Ambiguity is implicit in neural representations of the physical world. Previous work has examined how the visual system resolves ambiguous neural signals that represent various features, such as the percept resulting from rivalrous chromaticities or forms. Relatively little is known, however, about the contribution of un ambiguous neural representations to perceptual resolution of ambiguous ones. This is addressed here by measuring perceptual resolution of ambiguity by grouping, which is operationalized as the tendency for multiple similar ambiguous representations to be seen as identical to each other. Multiple chromatically ambiguous representations were created using interocular switch rivalry and presented together with a nearby but separate unambiguous (non-rivalrous) chromaticity. The magnitude of grouping the chromatic regions was compared when ambiguous regions were seen alone versus with unambiguous regions seen simultaneously. Contrary to prevailing theory that the resolution of the ambiguous percepts would follow the unambiguous ones, the ambiguous chromatic regions consistently appeared identical to each other, but their appearance was not found to be attracted to the unambiguous color percept. This supports the proposition that the ambiguity itself in a neural representation is a linking feature contributing to perceptual disambiguation.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ambiguity is a linking feature for interocular grouping

2022

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“…Theoretically, the amount of time seeing coherent color percepts with 30 discs could be due to chance. The measured durations, however, were always far longer than chance, which reveals grouping the discs in the process of perceptually resolving their 30 competing neural responses ( Shevell, 2019 ).…”

Section: Experiments 2: Thirty Dichoptic Discs Varied In Eye-swap Temporal Frequencymentioning

confidence: 98%

Binocularly-driven competing neural responses and the perceptual resolution of color

et al. 2021

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Competing rivalrous neural representations can be resolved at several levels of the visual system. Sustained percepts during interocular-switch rivalry (ISR), in which rivalrous left- and right-eye stimuli swap between eyes several times a second, often are attributed to competing binocularly driven neural representations of each rivalrous stimulus. An alternative view posits monocular neural competition together with a switch in eye dominance at the moment of each stimulus swap between eyes. Here, a range of experimental conditions was tested that would change the colors seen if mediated by eye dominance but not if by competition between binocularly driven responses. Observers viewed multiple chromatically rivalrous discs in various temporal and spatial patterns, and reported when all discs in view appeared the same color. Unlike typical ISR paradigms that swap the complete stimulus in each eye, some of the rivalrous discs were swapped at a different time, or faster frequency, than other discs. Monocular dominance of one eye at a time implies that all discs will rarely be seen as identical in color when some discs swap at a different frequency than others. On the other hand, competing binocularly driven neural responses are not affected by asynchronous swap timing among the individual discs. Results for every observer are in accord with competing responses at the level of binocularly driven, chromatically tuned neurons. Although an account based on eye dominance can be constructed using many small retinotopic zones that have independent timing for the moment of switching the dominant eye, competing binocularly driven responses are a more parsimonious explanation.

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“…This suggests that disambiguation in this case involves integration of information over relatively large visual distances. When multiple binocularly rivalrous stimuli (Section 2.3) occupy different parts of the visual field simultaneously, each resulting in the same pair of bistable percepts, they too can undergo correlated perceptual alternations (Shevell 2019). Figure 7 shows an example with 16 separate chromatically rivalrous objects, each with the same pair of rivalrous chromaticities (so each object sometimes appears red and sometimes green).…”

Section: Left Eyementioning

confidence: 99%

The Certainty of Ambiguity in Visual Neural Representations

Brascamp

Shevell

2021

Annu. Rev. Vis. Sci.

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Some images evoke bistable percepts: two different visual experiences seen in alternation while continuously viewing an unchanged stimulus. The Necker Cube and Rubin's Vase are classic examples, each of which gives alternating percepts of different shapes. Other bistable percepts are alternating colors or directions of motion. Although stimuli that result in salient bistability are rare and sometimes cleverly constructed to emphasize ambiguity, they have been influential for over 150 years, since the work of von Helmholtz, who considered them to be evidence for perceptual visual processes that interpret retinal stimuli. While bistability in natural viewing is uncommon, the main point of this review is that implicit ambiguity in visual neural representations is pervasive. Resolving ambiguity, therefore, is a fundamental and ubiquitous process of vision that routinely affects what we see, not an oddity arising from cleverly crafted images. This review focuses on the causes of widespread ambiguity, historical perspectives on it, and modern knowledge and theory about resolving it.

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Ambiguous chromatic neural representations: perceptual resolution by grouping

Cited by 3 publications

References 35 publications

Ambiguity is a linking feature for interocular grouping

Ambiguity is a linking feature for interocular grouping

Binocularly-driven competing neural responses and the perceptual resolution of color

The Certainty of Ambiguity in Visual Neural Representations

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