Visual Masking: A Unified Approach

Anbar, Sybille; Anbar, Dan

doi:10.1068/p110427

Cited by 20 publications

(38 citation statements)

References 27 publications

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“…This expression of lateral inhibition is what most models of visual masking deal with, which raises an interesting point. Francis (2000) found that four widely discussed models of masking produce nonmonotone performance functions because the strong target signal blocks the effect of the mask at brief SOAs (Anbar & Anbar, 1982;Bridgeman, 1977Bridgeman, , 1978Francis, 1997;Weisstein, 1968Weisstein, , 1972. Clearly, the present experiments, with black-on-white masks and targets, do not rely on mask blocking to produce nonmonotone backward masking, distinguishing our account from many of the bestknown explanations of visual backward masking.…”

Section: Related Ideasmentioning

confidence: 75%

Nonmonotone backward masking functions and brightness reversals

Stewart

Purcell

Pinkham

2011

Atten Percept Psychophys

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Increasing the target-field luminance aids detection for a simultaneously presented black target disc and a black masking annulus. At an intermediate interval separating the onset of the target from the mask, increasing the target-field luminance reduces target detection. This decrease in performance occurs with both temporal and spatial forced choice tasks. With a spatial forced choice, an observer's performance can fall below chance. We associate below-chance performance with a brightness reversal of the black target disc, such that the target disc appears brighter than its surround. The occurrence of brightness reversals follows from our model of the Broca-Sulzer effect, and nonmonotone masking functions result from a generalization of luminance summation.Keywords Visual backward masking . U-shaped functions . Broca-Sulzer effect . Brightness reversal . Metacontrast maskingThe detection of a briefly flashed target, such as a black disc, is sometimes suppressed by the onset of a second stimulus, the masking stimulus. When the target is followed by a surrounding figure, such as a black annulus, the interplay of target and mask is called backward masking. Under conditions of backward masking, both target detection and letter identification can decrease as the delay between the onset of the stimulus and the onset of the mask increases. The resulting nonmonotone performance curves are addressed by most accounts of visual masking . Under some conditions, however, target detection is worse than chance. No current explanation of masking accounts for below-chance performance.Our account of below-chance performance rests on three propositions: (i) A spatial two-alternative forced choice (2AFC) task can produce nonmonotone performance curves. For pronounced nonmonotone curves, detection can be worse than chance. (ii) These nonmonotone backward-masking curves represent a change in an observer's sensitivity for certain delays between target and mask onset, even for targets that fall on the fovea. A dark target, followed by an appropriate masking stimulus, sometimes appears to be brighter than its background, a phenomenon we have called a brightness reversal . Pronounced brightness reversals occur with black-on-white figures and can lead to below-chance target detection. (iii) Our conjecture is that brightness reversals result from the same combination of excitation, inhibition, and luminance summation that produces the Broca-Sulzer effect (Berman & Stewart, 1978a, 1978b, 1979Marks, 1974). These brightness reversals result in below-chance performance with a spatial 2AFC.

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Section: Related Ideasmentioning

confidence: 75%

Nonmonotone backward masking functions and brightness reversals

Stewart

Purcell

Pinkham

2011

Atten Percept Psychophys

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“…These include models by Weisstein (1968Weisstein ( , 1972, Bridgeman (1971Bridgeman ( , 1978, and Anbar and Anbar (1982). Each of these models has previously been used to account for many other aspects of masking (see, e.g., Francis & Hermens, 2002).…”

Section: Model Analysismentioning

confidence: 99%

Testing quantitative models of backward masking

Francis

Herzog

2004

Psychonomic Bulletin & Review

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We analyzed the relationship between U-shaped and monotonic-shaped masking functions, using both computer simulations of quantitative models and experimental data. Our analysis revealed that quantitative models of backward masking predict that U-shaped masking functions should appear for weak masks and monotonic masking functions should appear for strong masks. The models predict, moreover, that for a fixed target and experimental task, as the mask changes it is possible to go from U-shaped to monotonic-shaped masking functions. Significantly, the models predict that at each stimulus onset asynchrony between the target and the mask, the U-shaped function must have weaker masking than the monotonic-shaped function. Contrary to the predictions of the models, we show an experimental situation that generates masking functions that violate this prediction.

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“…There are a variety of computational models that account for the existence of both U-shaped and monotonicshaped masking functions (Anbar & Anbar, 1982;Bridgeman, 1971Bridgeman, , 1978Francis, 1997Francis, , 2003Weisstein, 1972). Francis (2000) identified a simple computational principle that accounts for the appearance of a U-shaped masking function and showed that this principle is used by all of these models.…”

Section: U-shaped Backward Maskingmentioning

confidence: 99%