The disappearance of dichoptically presented real and subjective contours

Halpern, Diane F.; Warm, Joel S.

doi:10.3758/bf03333869

Cited by 7 publications

(5 citation statements)

References 17 publications

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“…First, von der Heydt, Peterhaus, and Baumgartner (1984) clearly demonstrate that illusory contours are cortical in origin. Halpern and Warm (1984) generated subjective contours with dichoptic presentations of their luminous figures. These contours faded but the illusory contour persisted.…”

Section: Discussionmentioning

confidence: 99%

“…These studies indicate that persistence lasts beyond the visible persistence of the inducing stimulus as now found. Using luminous target fading of a subjective contour, Halpern and Warm (1981, 1984) report "when the inducing areas disappear, the subjective contours remain visible for a brief period via sensory and/or cognitive persistence" (1981, p. 232). They conclude, "In the jargon of information processing, top-down contours are less prone to disappearance than bottom-up ones" (1984, p. 436).…”

Section: Discussionmentioning

confidence: 99%

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The visible persistence of illusory contours.

Meyer¹,

Ming²

1988

Canadian Journal of Psychology / Revue canadienne de psychologi

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Two experiments were conducted which measured the visible persistence of illusory contours. Experiment 1 determined persistence for illusory contour squares presented for 50 ms. The illusory contours yielded 40 ms more persistence than controls. Phenomenologically, the subjective square would seem to hang in space after the inducing elements faded.The second experiment varied target duration from 50 to 1000 ms. For the control figures, visible persistence decreased with increasing target duration, the typical inverse duration effect. However, with the illusory contour targets, persistence first increased sharply with increasing target duration and then decreased. These results suggest that the time it takes for the visual system to construct the subjective contour yields an overall increase in persistence, and this ongoing processing can be seen over long target durations. These data further support the existence of cortical components of visible persistence.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

The visible persistence of illusory contours.

Meyer¹,

Ming²

1988

Canadian Journal of Psychology / Revue canadienne de psychologi

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“…Previous research has shown . that the performance of subjects on a variety of perceptual tasks improves as a function of task experience (see Gibson,1,969).…”

Section: Discussionmentioning

confidence: 99%

“…Frisby and Clatworthy pointed to the work of neurophysiologists Rodieck and Stone (1965) as salvaging a possible brightness contrast explanation of the illusory circle seen in Figure 2 (top panel). 1 Frisby and Clatworthy noted several properties of SCs that would seem to indicate an important role for brightness contrast in their perception. For example, SCs are usually strongest when black and white offset each other; offsetting gray and white attenuates the strength of the illusion.…”

Section: Lateral Inhibitory Brightness Contrastmentioning

confidence: 99%

Attentional processing and the subjective contour illusion.

Pritchard¹,

Warm²

1983

Journal of Experimental Psychology: General

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Leading explanations of the subjective contour illusion can be classified as being either "bottom-up" or "top-down." Bottom-up explanations assert that peripheral, physiological mechanisms often associated with the perception of real contours also account for subjective contour (SC) perception. In contrast, top-down explanations posit a more central locus of SC perception and are formulated on a molar, psychological level. A major aspect of bottom-up perceptual processing is that it is largely automatic. On the other hand, top-down processing implies a greater role for selective attention. In an effort to distinguish between bottom-up and top-down accounts of SC perception, the present investigation used a dual-task paradigm to test the relative attentional demands of real contour perception versus SC perception. In the primary task, subjects made speeded same-different discriminations of either paired SC forms or their real contour analogues. Half the subjects performed this primary task in conjunction with a six-digit short-term memory load secondary task. If subjective forms indeed impose a greater limited-capacity processing load than real forms, then the need to share processing capacity with a secondary task was expected to produce a greater increment in reaction time (RT) for subjective relative to real forms. The results indicated that the expected enhanced RT increment for subjective relative to real forms with the addition of a concurrent memory load was limited to same trials. This result implies that the nature of response indicators must be considered in assessing capacity requirements with the sort of dual-task paradigm used in the present investigation. Nevertheless, the fact that the increment in same RT with the addition of a concurrent memory load was greater for subjective relative to real forms accords with expectations derived from the notion that the perception of SCs is more attention demanding than that of real contours. If the interpretation of the present study is correct, then a comprehensive theory of SC perception will most likely be formulated within the top-down perspective of conceptually driven visual information processing.

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“…For subjective contours, disappearances occurred primarily in the physically present inducing areas, while the subjective edges remained visible, and there were fewer whole figure disappearances. In a later study, Halpern and Warm (1984) demonstrated that subjective contours could be rendered more stable than real contours under dichoptic viewing conditions (different portions of a figure are presented to each eye) wherein figure completion must be accomplished postretinally. The studies of Warm (1980, 1984) reveal some of the characteristics of fragmentation in illusory figures and, given the outcome of the dichoptic experiment, suggest that fragmentation of subjective contours may be more centrally determined than the fragmentation of real contours.…”

mentioning

confidence: 99%

Determinants of stability in the perception of subjective contour

Laurie

Warm

Dember

et al. 1994

Perception & Psychophysics

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The present study constituted an initial experimental effort to examine the fragmentation characteristics of subjective contours within the photopic and upper scotopic ranges of illumination. Four stimulus factors known to influence the visibility of subjective contours-target luminance, inducing area size and contrast, and contour orientation-were examined. Results indicated that subjective contours are indeed unstable perceptual phenomena. On the average, fragmentation or fading occurred after only 15 sec of observation, and some form of stimulus outage was present for 28 % of the viewing time of each stimulus. Fragmentation latency was significantly shorter and total time in fragmentation longer for diamond than for square contours, and total time in fragmentation varied inversely with inducing-area size. Fragmentation tended to occur in whole units rather than in isolated elements, a result reminiscent of the fading of real contours under impoverished viewing conditions.

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The disappearance of dichoptically presented real and subjective contours

Cited by 7 publications

References 17 publications

The visible persistence of illusory contours.

The visible persistence of illusory contours.

Attentional processing and the subjective contour illusion.

Determinants of stability in the perception of subjective contour

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