Completeness and spatial distribution of mask contours as factors in visual backward masking.

Sherrick, Michael F.; Dember, William N.

doi:10.1037/h0028928

Cited by 12 publications

(22 citation statements)

References 5 publications

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“…We used a circular mask instead of a tightly fitting square one because the latter would crowd the target whereas the former would not (Kooi et al, 1994; Levi, 2008). However, a circular mask might also result in weaker masking than a square one (Sherrick & Dember, 1970; Werner, 1935), but this is known to be the case only with a foveal presentation. Using peripheral presentation Enns and Di Lollo (1997) showed that contour proximity did not have much of an effect in terms of masking strength.…”

Section: Methodsmentioning

confidence: 99%

Recovery of a crowded object by masking the flankers: Determining the locus of feature integration

Chakravarthi

Cavanagh

2009

Journal of Vision

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Object recognition is a central function of the visual system. As a first step, the features of an object are registered; these independently encoded features are then bound together to form a single representation. Here we investigate the locus of this “feature integration” by examining crowding, a striking breakdown of this process. Crowding, an inability to identify a peripheral target surrounded by flankers, results from “excessive integration” of target and flanker features. We presented a standard crowding display with a target C flanked by four flanker C's in the periphery. We then masked only the flankers (but not the target) with one of three kinds of masks—noise, metacontrast, and object substitution—each of which interferes at progressively higher levels of visual processing. With noise and metacontrast masks (low-level masking), the crowded target was recovered, whereas with object substitution masks (high-level masking), it was not. This places a clear upper bound on the locus of interference in crowding suggesting that crowding is not a low-level phenomenon. We conclude that feature integration, which underlies crowding, occurs prior to the locus of object substitution masking. Further, our results indicate that the integrity of the flankers, but not their identification, is crucial for crowding to occur.

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Section: Methodsmentioning

confidence: 99%

Recovery of a crowded object by masking the flankers: Determining the locus of feature integration

Chakravarthi

Cavanagh

2009

Journal of Vision

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“…Despite the differences, the overall influence of increasing mask duration is the same for both studies and simulations. Sherrick & Dember (1970) demonstrated that the amount and spatial layout of mask contour affected masking strength. The target in their display was a brief (15 milliseconds) black disk that appeared in one of two locations.…”

Section: Mask Durationmentioning

confidence: 99%

“…For masks with equal contour percentages, masking is stronger when the contour is distributed rather than continuously aligned. (a) Psychophysical data redrawn from Sherrick & Dember (1970). (b) Target boundary durations from model simulations.…”

Section: Mask Durationmentioning

confidence: 99%

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Cortical dynamics of lateral inhibition: Metacontrast masking.

Francis

1997

Psychological Review

124

201

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The dynamic properties of a neural network model of visual perception, called the boundary contour system, explain characteristics of metacontrast visual masking. Computer simulations of the model, with a single set of parameters, demonstrate that it accounts for 9 key properties of metacontrast masking: Metacontrast masking is strongest at positive stimulus onset asynchronies (SOAs); decreasing target luminance changes the shape of the masking curve; increasing target duration weakens masking; masking effects weaken with spatial separation; increasing mask duration leads to stronger masking at shorter SOAs; masking strength depends on the amount and distribution of contour in the mask; a second mask can disinhibit the masking of the target; such disinhibition depends on the SOA of the 2 masks; and such disinhibition depends on the spatial separation of the 2 masks. No other theory provides a unified explanation of these data sets. Additionally, the model suggests a new analysis of data related to the SOA law and makes several testable predictions.

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“…Sherrick and Dember (1970) showed that incomplete contours could produce metacontrast masking, and that the masking magnitude grew monotonically with contour completion. We extend this work to show that a similar result is not obtained in paracontrast and that this asymmetry can be interpreted in terms of the spatiotemporal properties of the inhibiting cells.…”

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confidence: 99%

Masking with minimal contours: Selective inhibition with low spatial frequencies

Gilden

MacDonald

Lasaga

1988

Perception & Psychophysics

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Paracontrast and metacontrast magnitudes were measured in a target identification task. A particular class of illusory contours is described that did not mask in the paracontrast condition but did show a large metacontrast magnitude. The discontinuity in the masking function is interpreted in terms of the Fourier decomposition of the visual scene that is performed by cells selectively responsive to discrete bands of spatial frequencies. The class of contours that we describe can only mask through inhibition generated by their low spatial frequencies. These results are consistent with recent models of masking based on two independent modes of inhibition-within sustained visual channels, and between sustained and transient visual channels.One of the most important developments in visual psychophysics has been the discovery and classification of cells that are selectively responsive to different bands of spatial frequencies. Psychophysical and electrophysiological measurements (for reviews, see Breitmeyer, 1984;De Valois & De Valois, 1980;Graham, 1981;Shapley & Lennie, 1985; chap. 4) give evidence that the visual scene is represented in early vision in terms of a coarse Fourier decomposition, and that different pieces of the spectrum are processed by independent channels. Recently these ideas have been introduced into a theoretical framework for visual pattern masking (Breitmeyer, 1984;Breitmeyer & Ganz, 1976).Pattern masking is a phenomenon in which perceived contrast or clarity of contour for one stimulus decreases as a result of the presentation of a second stimulus. In paracontrast (mask precedes target) and metacontrast (target precedes mask) masking, there is no overlap between mask and target contour. In this paradigm, it is generally possible to identify that a target has been shown, even when the target suffers contrast reduction and blurring (Breitmeyer, 1984). The loss of contour detail and contrast without complete elimination of stimulus detection suggests that masking operates by differentially affecting the processing of the high-spatial-frequency content of the stimulus. The central idea of Breitmeyer and Ganz's (1976) theory is that there are two independent modes of inhibition acting on the channels that process high spatial frequencies. According to this theory, paracontrast masking is achieved primarily by intrachannel inhibition caused by an antagonistic center-surround interaction within the The authors wish to thank Jack McArdle for several helpful discussions concerning the experimental design and analysis of the data. We also want to acknowledge conversations with Dennis Proffitt and the advice and encouragement he offered. D.G. was supported by NIH Grant HD0703tH>1 during the course of this work. Address correspondence to David Gilden, Department of Psychology, Gilmer Hall, University of Virginia, Charlottesville, VA 22903-2477. receptive field of a single cell. It is theorized that metaeontrast masking is produced by center-surround interactions (as in paracontrast) and by an addition...

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Completeness and spatial distribution of mask contours as factors in visual backward masking.

Cited by 12 publications

References 5 publications

Recovery of a crowded object by masking the flankers: Determining the locus of feature integration

Recovery of a crowded object by masking the flankers: Determining the locus of feature integration

Cortical dynamics of lateral inhibition: Metacontrast masking.

Masking with minimal contours: Selective inhibition with low spatial frequencies

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