Subjective contours 1900–1990: Research trends and bibliography

Purghé, Franco; Coren, Stanley

doi:10.3758/bf03212255

Cited by 24 publications

(9 citation statements)

References 278 publications

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“…It is unlikely that contour-detecting cells in the primary visual cortex solely facilitate this perception, as edge detection can be characterized as a complex and multidimensional process in which various cells analyze and extrapolate information from the visual field across the stage(s) of visual processing (Hubel & Wiesel, 1962). Therefore, it appears that the perception of illusory contours represents the creation of an imaginative figure, produced by a visual system with a proclivity to complete figural components (Gerbino & Salmaso, 1987;Kanizsa, 1974;Purghé & Coren, 1992).…”

Section: Discussionmentioning

confidence: 99%

Illusory contour perception in domestic dogs

et al. 2019

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One way to better understand how animals visually perceive their environment is to assess the way in which visual information is interpreted and adapted based on preconceptions. Domestic dogs represent a unique species in which to evaluate visual perception as recent findings suggest they may differ from humans and other animal species in terms of their susceptibility to geometric visual illusions. Dogs have demonstrated human-like, reversed, and null susceptibility depending on the type of illusion. To further evaluate how dogs perceive their environment, it is necessary to perform additional assessments of visual perception. One such assessment is the perceptual filling-in of figures, which may be invoked when presented with illusory contours. Six dogs were assessed on their perception of the Ehrenstein illusory contour illusion in a two-choice size-discrimination task. Dogs, as a group, demonstrated equivocal perception of illusory contours. Some individual dogs, however, demonstrated human-like perception of the subjective contours, providing preliminary evidence that this species is capable of perceiving illusory contour illusions, thereby improving the current understanding of canine visual perception capabilities. Additional assessments using alternative illusory contour illusions are needed to clarify these results and identify features that underpin the individual differences observed.

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Section: Discussionmentioning

confidence: 99%

Illusory contour perception in domestic dogs

et al. 2019

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“…A lack of insight happens is not restricted to the lab; it also occurs in the annals of history. As Purghé and Coren (1992) pointed out, 19 th century scientists like Helmoholtz, Wundt, Ebbinghaus, Sanford, and Titchner all published figures with illusory contours, but never remarked upon their phenomenal existence. Not until the next century were interpolated figures formally "discovered" and investigated (Schumann, 1904; Kanizsa, 1955).…”

Section: Discussionmentioning

confidence: 99%

Is interpolation cognitively encapsulated? Measuring the effects of belief on Kanizsa shape discrimination and illusory contour formation

Keane

Papathomas

et al. 2012

Cognition

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Contour interpolation is a perceptual process that fills-in missing edges on the basis of how surrounding edges (inducers) are spatiotemporally related. Cognitive encapsulation refers to the degree to which perceptual mechanisms act in isolation from beliefs, expectations, and utilities (Pylyshyn, 1999). Is interpolation encapsulated from belief? We addressed this question by having subjects discriminate briefly-presented, partially-visible fat and thin shapes, the edges of which either induced or did not induce illusory contours (relatable and non-relatable conditions, respectively). Half the trials in each condition incorporated task-irrelevant distractor lines, known to disrupt the filling-in of contours. Half of the observers were told that the visible parts of the shape belonged to a single thing (group strategy); the other half were told that the visible parts were disconnected (ungroup strategy). It was found that distractor lines strongly impaired performance in the relatable condition, but minimally in the non-relatable condition; that strategy did not alter the effects of the distractor lines for either the relatable or non-relatable stimuli; and that cognitively grouping relatable fragments improved performance whereas cognitively grouping non-relatable fragments did not. These results suggest that 1) filling-in effects during illusory contour formation cannot be easily removed via strategy; 2) filling-in effects cannot be easily manufactured from stimuli that fail to elicit interpolation; and 3) actively grouping fragments can readily improve discrimination performance, but only when those fragments form interpolated contours. Taken together, these findings indicate that discriminating filled-in shapes depends on strategy but filling-in itself may be encapsulated from belief.

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“…The appearance of two books on this topic (Kanizsa 1979;Petry and Meyer 1987) and an annotated bibliography listing some 450 entries (Purghe and Coren 1992), suggests that a critical discussion of these issues has become a matter of urgency. The aim of this article is to present the empirical data on illusory contours and to evaluate the hypotheses proposed to explain them.…”

Section: Introductionmentioning

confidence: 99%

Phenomena of Illusory Form: Can We Bridge the Gap between Levels of Explanation?

Spillmann

Dresp²

1995

Perception

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Abstract. The study of illusory brightness and contour phenomena has become an important tool in modern brain research. Gestalt, cognitive, neural, and computational approaches are reviewed and their explanatory powers are discussed in the light of empirical data. Two wellknown phenomena of illusory form are dealt with, the Ehrenstein illusion and the Kanizsa triangle. It is argued that the gap between the different levels of explanation, bottom-up versus top-down, creates scientific barriers which have all too often engendered unnecessary debate about who is right and who is wrong. In this review of the literature we favour an integrative approach to the question of how illusory form is derived from stimulus configurations which provide the visual system with seemingly incomplete information. The processes that can explain the emergence of these phenomena range from local feature detection to global strategies of perceptual organisation. These processes may be similar to those that help us restore partially occluded objects in everyday vision. To understand better the Ehrenstein and Kanizsa illusions, it is proposed that different levels of analysis and explanation are not mutually exclusive, but complementary. Theories of illusory contour and form perception must, therefore, take into account the underlying neurophysiological mechanisms and their possible interactions with cognitive and attentional processes.

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Subjective contours 1900–1990: Research trends and bibliography

Cited by 24 publications

References 278 publications

Illusory contour perception in domestic dogs

Illusory contour perception in domestic dogs

Is interpolation cognitively encapsulated? Measuring the effects of belief on Kanizsa shape discrimination and illusory contour formation

Phenomena of Illusory Form: Can We Bridge the Gap between Levels of Explanation?

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