Three-part Oppel-Kundt illusory figure

Bertulis, Algis; Surkys, Tadas; Bulatov, Aleksandr; Gutauskas, Algirdas

doi:10.3390/medicina45110112

Cited by 4 publications

(4 citation statements)

References 8 publications

(6 reference statements)

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“…Some additivity of illusory effects was revealed in experiments with the three-part Oppel-Kundt figure (one empty interval flanked by two filled ones, Fig. 1B), which induced an illusion about a quarter stronger than that caused by the conventional two-part figure (Bertulis et al 2009). Although different modifications of the filled-space illusion have been rather well studied experimentally, at present there is as yet no generally accepted explanation for the occurrence of this visual phenomenon.…”

Section: Research Papermentioning

confidence: 94%

An effect of continuous contextual filling in the filled‑space illusion

Bulatov¹,

Bulatova²,

Surkys³

et al. 2017

Acta Neurobiologiae Experimentalis

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In the filled-space (or Oppel-Kundt) illusion, the filled part of the stimulus for most observers appears longer in comparison with the empty one. In the first two experimental series of the present study, we investigated the illusory effect as a function of continuous filling (by a shaft-line segment) of the reference spatial interval of the three-dot stimulus. It was demonstrated that for the fixed length of the reference interval, the magnitude of the illusion increases non-linearly with the shaft length. For the fixed length of the shaft, the illusion magnitude gradually decreases with the lengthening of the reference interval. In the third series, psychophysical examination of the conventional Oppel-Kundt stimulus with different number of equally spaced elements (dots) subdividing its filled part was performed. Based on the analysis of the functional dependencies established, we have proposed a simple computational model that was successfully applied to fit the experimental data obtained in the present study.

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Section: Research Papermentioning

confidence: 94%

An effect of continuous contextual filling in the filled‑space illusion

Bulatov¹,

Bulatova²,

Surkys³

et al. 2017

Acta Neurobiologiae Experimentalis

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“…49–52) rather than slant perception. A typical Oppel-Kundt figure uses tick lines for the filling elements, while the illusion also occurs with dots (Bertulis et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

“…However, it seemed doubtful that the stimuli with two disks yielded the Oppel-Kundt illusion because the illusion weakens for stimuli with few filling elements (<5) and even reverses (i.e., underestimation of length) for stimuli filled with one element (Bertulis et al, 2009; Coren & Girgus, 1978, p. 27; Mikellidou & Thompson, 2014; Rentschler et al, 1981). Taken together, it is unlikely that the illusory effect shown in Figure 1A is wholly attributable to the Oppel-Kundt illusion.…”

Section: Discussionmentioning

confidence: 99%

The contributions of surface features and contour shapes to object slant perception

Niimi

2023

i-Perception

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Humans perceive 3D shapes even from 2D images. A slant can be perceived from images of slanted rectangular objects, which include texture gradients and linear perspective contours. How does the visual system integrate and utilize these pictorial depth cues? A new visual illusion that provides some insights into this issue was examined. A box-like object with disk figures drawn on its upper surface was rendered in a linear perspective image. The length of the object's upper surface side line was overestimated, probably due to the foreshortened disks serving as slant cues. This illusory effect occurred even when observers estimated the line length on the image plane, suggesting that the slant perception from the disks was mandatory. Five experiments revealed that multiple depth cues were utilized for the slant perception; the aspect ratio of the disks, texture gradients, trapezium/parallelogram contours, and the side surfaces of the box-like object. However, foreshortened disks outside the object were not utilized as depth cues. These results suggested that various depth cues belonging to the target object are integrated for the slant perception.

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“…Three spatial interval stimuli (Fig. 1) were used in the experiments, as possessing left-right symmetry and producing stronger illusions; the three-part O-K figure with two filled intervals flanking the empty part induced a 25% stronger illusion than the two-part figure with one filled interval (Bertulis et al 2009). The control stimulus was comprised of four spots (Fig.…”

Section: Stimuli and Apparatusmentioning

confidence: 99%

Summation of two illusions of extent

Bertulis¹,

Surkys²,

Bielevičius³

2018

Acta Neurobiologiae Experimentalis

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In the present visual psychophysical study, the Oppel-Kundt and and Müller-Lyer illusion magnitudes were measured separately (by single figures) and in combination (by two patterns superposed spatially). Data for 30 subjects revealed extensive variability both for the separate and combined illusion strength. Nevertheless, the effect of addition of the perceived length distortions was established. The combined illusions were significantly stronger than the separate ones. Dynamics of the misperceptions summation was studied by varying length of the Müller-Lyer wings in the superposed stimuli. According to the experimental data obtained, the two misperceptions in length occurred and combined into sensory response varying in dependence on the spatial parameters of the superposed stimuli and on the individual experimental accomplishment. The data supported an explanation for the origin of the filled/unfilled illusion: overestimate of a filled interval length developed due to the spatiotemporal integration along a continuous excitation path elicited by the real or imaginary contours of the filling.

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Three-part Oppel-Kundt illusory figure

Cited by 4 publications

References 8 publications

An effect of continuous contextual filling in the filled‑space illusion

An effect of continuous contextual filling in the filled‑space illusion

The contributions of surface features and contour shapes to object slant perception

Summation of two illusions of extent

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