The Global Figural Characteristics in the Zöllner Illusion

A broad collection of illusions belonging to the Zöllner and the Poggendorff families, including new variants -in particular, tilted and tilting squares -are examined in the light of two possible formal principles : a principle of regression to right angles (RRA) and a principle of "orthogonal expansion", which is a perceptual expansion of the extent perpendicularly to the inducing lines. The domains of validity of the two principles are compared. We propose that RRA is more pertinent when the target line is explicitely present and makes real intersections with the inducing lines. Orthogonal expansion can produce RRA as a side-effect. It would be more pertinent when there are several parallel or nearly parallel inducing lines, and it does not require the presence of a real target. Both principles may be grounded on neurophysiological mechanisms.Orientation detectors would influence each other in the orientation domain, generating RRA and accounting for the illusions of the Poggendorff family. They would also influence each other in the extent domain, generating orthogonal expansion, and accounting for the illusions of the Zöllner family.

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“…We have already encountered the stimulus of Parlangeli and Roncato (1995) shown in Fig. 1g, in which the inducers are broken lines.…”

Section: Discussionmentioning

confidence: 99%

“…1g, we have a stimulus, designed by Parlangeli and Roncato (1995) resembling the Zöllner stimulus of Fig. 1a, but this time each segment is a line broken in three steps.…”

Section: Zöllner Illusion and Variantsmentioning

confidence: 99%

Orthogonal Expansion: A Neglected Factor in Tilt Illusions

Ninio

Pinna

2006

PSYCHOLOGIA -An International Journal of Psychological Sciences

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“…However, as shown in Figure 6B, crossing is not essential for the effect: Here, the parallel target lines also look non-parallel in much the same way as in Figure 6A, although the oblique dashes do not cross them but only touch them on one side, and thus the number of both acute and obtuse angles is halved (Hering, 1861). Touching is not essential either, as shown in Figure 6C, in which the target lines still look non-parallel, although they are not touched by the oblique dashes, so that no actual, visually specified angles between lines and dashes are formed at all (Oyama, 1975; Parlangeli & Roncato, 1995). Surprisingly, as shown in Figure 6D, even the target lines are not essential for the illusion, as the empty interspaces between the oblique dashes look non-parallel, in a similar fashion as the target lines in the preceding figures (Earle & Maskell, 1995)!…”

Section: An Augmented Framework For Illusionsmentioning

confidence: 99%

What Are Visual Illusions?*

Todorović

2020

Perception

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Visual illusions have been a popular topic of study for a long time, but in recent years, a number of authors have questioned the coherence of this notion. This article deals in depth with ways in which illusions have been, could be, and should be defined and with various criticisms and different conceptions of the notion of illusions. After a review of definitions of illusions in the relevant literature, a more comprehensive but also more restrictive framework is presented, involving both veridicality and illusoriness, and is illustrated using two variants of a 2 × 2 scheme for the presentation of illusions. Many different aspects of illusions are discussed. A set of criteria for illusionhood is listed. Criticisms of the notion of illusions are presented, commented upon, and responded to. Conceptions of illusions differing from the one advocated here are discussed. Throughout the paper, novel variations of illusions are shown, and problems with accounts of some well-known illusions are noted. Examples of strong context effects which are not considered to be illusions are presented. It is concluded that the notion of visual illusions, suitably reformulated, is still viable.

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“…The Zöllner illusion is observed when the acute angle is between 0° and 90° (Morinaga, 1933; Parlangeli & Roncato, 1995; Wallace & Crampin, 1969), but the maximum magnitude is obtained when the acute angle is between 10° and 30° (Maheux, Townsend, & Gresock, 1960; Morinaga, 1933; Oyama, 1975; Wallace & Crampin, 1969). The Zöllner illusion is stronger when induced lines are rotated 45° from the vertical or horizontal than when they are vertical or horizontal, respectively (see Oyama, 1960).…”

Section: Zöllner Illusionmentioning

confidence: 99%

Tilt illusions after Oyama (1960): A review¹

Kitaoka¹

2007

Jpn Psychol Res

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This article reviews the study of tilt illusions by focusing on new illusions or new demonstrations reported by Japanese researchers after the review of Oyama (1960). Steady progress was observed in a variety of illusions. In particular, the development of the study of the Café Wall illusion and its related illusions during the past decade was remarkable. The study of the spiral illusion has also progressed dramatically.Key words: tilt illusion, orientation, Zöllner illusion, Fraser illusion, Café Wall illusion, spiral illusion.Visual illusion refers to the phenomenon that some properties of the percept of an object are different from those as they "really" are. Visual illusion includes the illusion of shape, lightness, color, motion, etc. (see Kitaoka, 2005a). The illusion of shape, traditionally called "geometrical" illusion, includes the illusion of orientation, size, and position (Robinson, 1972). This article focuses on the illusion of orientation, that is, tilt illusion.Tilt illusion refers to apparent tilt of a line, bar or an edge. For example, parallel lines do not appear to be parallel, a straight line appears to curve, or the angle formed by two lines appears to be larger or smaller than it really is. The aim of this article is to review the study of tilt illusions reported by Japanese researchers after the review of Oyama (1960), with a focus on new illusions or new demonstrations. Zöllner illusion Zöllner illusionThe Zöllner illusion is the apparent expansion of the acute angle formed by two crossing lines. Figure 1 shows an example in which a horizontal line appears to tilt clockwise because it is crossed by oblique lines that tilt counterclockwise from the horizontal.The Zöllner illusion is observed when the acute angle is between 0 ° and 90 ° (Morinaga, 1933;Parlangeli & Roncato, 1995;Wallace & Crampin, 1969), but the maximum magnitude is obtained when the acute angle is between 10 ° and 30 ° (Maheux, Townsend, & Gresock, 1960;Morinaga, 1933;Oyama, 1975;Wallace & Crampin, 1969). The Zöllner illusion is stronger when induced lines are rotated 45 ° from the vertical or horizontal than when they are vertical or horizontal, respectively (see Oyama, 1960). Oyama (1975Oyama ( , 1977 revealed that, in the Zöllner illusion, interactions between two lines are limited to narrow visual fields and he 1 Part of this research was supported by a Grant-in-Aid for Scientific Research awarded by the Japan Society for the Promotion of Science (Nos. 18203036 and 16530480). Deep gratitude is extended to Dr Tadasu Oyama for his encouragement.2 Correspondence concerning this article should be sent to: Akiyoshi Kitaoka, Department of Psychology, Ritsumeikan University, Toji-in Kitamachi, Kita-ku, Kyoto 603-8577, Japan. (Email: akitaoka@lt.ritsumei.ac.jp) Figure 1. The Zöllner illusion. The horizontal line appears to tilt clockwise.

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The Global Figural Characteristics in the Zöllner Illusion

Cited by 14 publications

References 25 publications

Orthogonal Expansion: A Neglected Factor in Tilt Illusions

Orthogonal Expansion: A Neglected Factor in Tilt Illusions

What Are Visual Illusions?*

Tilt illusions after Oyama (1960): A review¹

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The Global Figural Characteristics in the Zöllner Illusion

Cited by 14 publications

References 25 publications

Orthogonal Expansion: A Neglected Factor in Tilt Illusions

Orthogonal Expansion: A Neglected Factor in Tilt Illusions

What Are Visual Illusions?*

Tilt illusions after Oyama (1960): A review1

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Tilt illusions after Oyama (1960): A review¹