Determinants of subjective contour: Bourdon illusions and “unbending” effects

Wenderoth, Peter; Criss, Gerard; Zwan, Rick van der

doi:10.3758/bf03211594

Cited by 4 publications

(6 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A number of researchers have employed illusory contour versions of classical illusions involving impaired estimations of orientations. It appears that illusory contours facilitate the Bourdon illusion (Walker & Shank, 1987, 1988a, 1988bWenderoth, Criss, & van der Zwan, 1990) but slightly decrease the effect of the Poggendorff illusion (Day, Dickinson, & lory, 1977;Goldstein & Weintraub, 1972;Meyer & Garges, 1979). General equivalence in orientation estimation is a strong, though not unequivocal, argument for early representation of illusory contours, Time course studies.…”

Section: Psychophysical Similarities Between Real and Illusory Contoursmentioning

confidence: 99%

Illusory contours: Toward a neurally based perceptual theory

Lesher

1995

Psychon Bull Rev

View full text Add to dashboard Cite

Although illusory contours were first described nearly a century ago, researchers have only recently begun to approach a consensus on the processes underlying their formation. Neurophysiological and psychophysical evidence indicate that neural mechanisms of the early visual cortex subserve illusory contour generation, although cognitive factors play important roles in determining the fmal percept. I summarize experiments concerning the determinants of illusory contour strength and form, concentrating on findings particularly relevant to modeling. After establishing arguments for the early generation of illusory contours, I provide an overview of formation theories, culminating with descriptions of neural models. The constraints that experimental data place on models are outlined, and neural models are evaluated with respect to these constraints. Throughout the review,I indicate where further experimental and modeling research are critical.Schumann introduced the first illusory contour, depicted in Figure 1a, in 1900, noting that a central "white rectangle with sharply defined contours appears, which objectively are not there." Schumann had discovered and noted two salient features of illusory figures: sharp edges in regions of homogeneous luminance, and a brightening within the figure. Perhaps because this stimulus failed to yield particularly convincing illusory contours, it was not until more than 50 years later that illusory contours became a topic for activeresearch. Although Ehrenstein (1941) demonstrated stimuli with salient illusory contours, it is remarkable that he failed to note their existence in the text of his article explicitly, commenting instead only on illusory brightening effects. Kanizsa's (1955) stunning figures, examples of which are depicted in Figures Iband 1c, produced extremely sharp, salient contours along with obvious brightening, initiating a wave of research.Although there have been a number ofexcellent illusory contour review papers Meyer & Petry, 1987;Parks, 1984), research advances in the psychophysical, neurophysiological, and modeling domains have been more than sufficient to mandate a new summary ofthe literature. Inthis review, I will not only present more recent data, but also employ an approach to the summaries that is markedly different from those previously taken. At the time of the earlier reviews, determination of the locus of formation of illusory contours was the central issue in illusory contour research, a fact reflected in the structure of the review papers. Experimental results were presented primarily in the historical context of supporting or refut-I would like to thank Ennio Mmgolla of Boston University for generously providing many helpful comments and suggestions during the development ofthis review.

show abstract

Section: Psychophysical Similarities Between Real and Illusory Contoursmentioning

confidence: 99%

Illusory contours: Toward a neurally based perceptual theory

Lesher

1995

Psychon Bull Rev

View full text Add to dashboard Cite

show abstract

“…Finally, the effect in Figure IF exceeded that in Figure IE. Dayet al (1990) correctly point out that this last result probably relates to the apparent divergence of the upper ends of oblique parallels, which, for unknown reasons, is greater for right-tilted lines (Carpenter & Blakemore, 1973;Rochlin, 1955 We have noted (Wenderoth, Criss, & van der Zwan, 1990;Wenderoth & O'Connor, 1987a, 1987bWenderoth et al, 1986) that when subjects were required to set a chevron placed adjacent to the Bourdon edge to match it ( Figure IG), most observers (including myself) tended first to try to set the upper chevron arm parallel to the edge of the upper wedge, to repeat this for the lower edge, and then to make a second-stage, global judgment in which the matching chevron was bent even more. This two-stage process manifested itself in the finding that chevron matches were greater than the sum of individual and single parallel matches ( Figure IH) to each wedge individually (Wenderoth et al, 1986).…”

Section: Statementioning

confidence: 84%

“…and Day, Mitchell;and Stecher (1990) Wenderoth, Criss, and van der Zwan (1990), Wenderoth and O'Connor (1987a, 1987b), and Wenderoth, O'Connor, and Johnson (1986 Day (1990) and Day et aL (i990).…”

mentioning

confidence: 99%

“…2006, Australia. 393 selective neurons, and the other suggested that the test (straight) and inducing (bent) sides of the Bourdon figure are confused with each other. Wende roth et al (1986;Wenderoth & O'Connor, 1987a, 1987bWenderoth, Criss, & van der Zwan, 1990) suggested that the illusion is a manifestation of conflicting signals arising in separate and parallel neural channels coding orientation, position, and collinearity. However, Wenderoth and his colleagues have also used the term confusion.…”

mentioning

confidence: 99%

See 1 more Smart Citation

The basis of the Bourdon illusion

Wenderoth

1991

Perception & Psychophysics

Self Cite

View full text Add to dashboard Cite

show abstract

“…1a). This effect is stronger in subjective contours than in real contours (Walker & Shank, 1987;Walker & Shank, 1988a, 1988bWenderoth et al, 1990).…”

Section: Introductionmentioning

confidence: 84%

Optimizing the strength of the Bourdon effect by varying the triangle arrangement

Devinck¹,

Quaireau²

2021

Atten Percept Psychophys

View full text Add to dashboard Cite

The Bourdon illusion refers to the perceived bentness of the straight collinear edges when two right-angled triangles are placed apex to apex. We studied this illusion using a cancellation method. In the first of three experiments, we manipulated the apex angle, with six different angles ranging from 4°to 45°. Results indicated that the Bourdon illusion is strongest when the angle is around 12°. In the second experiment, we compared four scalene triangles with a right-angled triangle. The angular shift was most salient when the shape corresponded to a right-angled triangle. In the third experiment, the patterns were created by varying the size of one right-angled triangle while holding the size of the second right-angled triangle constant. Results indicated that the Bourdon illusion was strongest when both right-angled triangles were of equal size. Our data suggest that the Bourdon illusion depends critically upon the specific arrangement of shapes in the display.

show abstract

Determinants of subjective contour: Bourdon illusions and “unbending” effects

Cited by 4 publications

References 18 publications

Illusory contours: Toward a neurally based perceptual theory

Illusory contours: Toward a neurally based perceptual theory

The basis of the Bourdon illusion

Optimizing the strength of the Bourdon effect by varying the triangle arrangement

Contact Info

Product

Resources

About