Temporal brightness enhancement: Studies of individual differences

Bowen, Richard W.

doi:10.3758/bf03207494

Cited by 5 publications

(6 citation statements)

References 16 publications

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“…With the 640-msec comparison stimulus, functions for Type A observers (top panel, left side) at both asynchrony conditions have a minimum at 80 msec (a brightness enhancement effect). This pattern of discrimination completely replicates previous work (e.g., Bowen, 1984), and it implies that the 80-msec test pulse appeared brighter than all shorter or longer test pulses, since it was judged brighter than the 640-msec comparison on the greatest percentage of trials. Now, if an 80-msec pulse is itself used as a comparison pulse for Type A observers, an 80-msec test pulse should still be the minimum of the function, but the minimum level should be near 50 % (80 msec compared with 80 msec) rather than near 0 % (80 msec compared with 640 msec).…”

Section: Resultssupporting

confidence: 88%

“…Error bars indicate 95 % confidence intervals. The observers were categorized as Type A, B, or C on the basis of the data for the 640-msec comparison pulse, as in previous studies (see Bowen, 1984). The criterion for the occurrence of brightness enhancement was a binomial one (Bowen & Markell, 1980): 30% or less of' '640-msec comparison pulse judged brighter" at any pulse duration was taken as evidence of brightness enhancement, since 6 trials out of 20 is significantly lower (p < .057) than 50% in a binomial distribution, assuming a probability of .5 for responding "comparison pulse brighter."…”

Section: Resultsmentioning

confidence: 99%

“…Here we employed both a short comparison pulse (80 msec) and a long one (640 msec). (If brightness enhancement occurs, an 80-msec pulse will have the greatest brightness under our stimulus conditions; Bowen, 1984. ) We asked whether the pattern of results obtained with a short comparison pulse could be exactly predicted from the well-established pattern determined with the long comparison pulse.…”

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confidence: 95%

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Consistency of individual differences in brightness perception

Bowen

1986

Perception & Psychophysics

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In previous studies, we have measured individual differences in simultaneous brightness discrimination between a long-duration (500 msec or more) comparison pulse and a set of briefer test pulses of the same luminance. Some observers judge the comparison pulse to be brighter than all test pulses in a range from 20 to 320 msec. Other observers exhibit temporal brightness enhancement: a test pulse of 80 msec for our stimulus conditions is judged brighter than the comparison pulse. Individual differences depend upon the temporal asynchrony between test and comparison pulses. Observers designated Type A show temporal brightness enhancement for both simultaneous onset of test and comparison pulse and for simultaneous offset of the pulses. Type B observers exhibit brightness enhancement for simultaneous offset of pulses but not for simultaneous onset. Type C observers do not exhibit brightness enhancement effects. Here we use both short (80 msec) and long (640 msec) pulses as the comparison stimuli. We replicate our previous pattern of individual differences for the long comparison stimulus. For the short comparison stimulus, brightness discrimination functions for the three classes of observers are exactly predicted from the patterns obtained with the conventional long comparison pulse. This confirms the generality of individual differences in pulse brightness perception and shows that they do not depend upon the particular stimulus conditions selected for the discrimination task.

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Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 99%

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confidence: 95%

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Consistency of individual differences in brightness perception

Bowen

1986

Perception & Psychophysics

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“…If brightness reversals lead to below-chance performance, then coaching should improve an observer's performance at a below-chance SOA (Bowen, 1984). We tested this idea by explaining to each observer what a brightness reversal is.…”

Section: Experiments 4: Spatial Forced Choice With Knowledge Of Performentioning

confidence: 99%

“…The weight function w is the Gamma density in Equation (1), with σ r replaced by σ w = 6.18 ms (Bowen, 1984;Watson, 1986). Note that the net output n is a function of time, while the Broca-Sulzer function represents brightness that changes with duration τ (Berman & Stewart, 1978a, 1978b, 1979Wasserman & Kong, 1974).…”

Section: A Formal Modelmentioning

confidence: 99%

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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Psychophysics of lateral tachistoscopic presentation

Kitterle

1986

Brain and Cognition

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Temporal brightness enhancement: Studies of individual differences

Cited by 5 publications

References 16 publications

Consistency of individual differences in brightness perception

Consistency of individual differences in brightness perception

Nonmonotone backward masking functions and brightness reversals

Psychophysics of lateral tachistoscopic presentation

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