Illusion decrement and transfer of illusion decrement in real- and subjective-contour Poggendorff figures

Beckett, Peter A.

doi:10.3758/bf03208062

Cited by 20 publications

(7 citation statements)

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“…Experiment 2, therefore, investigated the effect of intermittent-inspection on decrement for the Poggendorff illusion. This illusion was selected because it is a different type of distortion from the M-L illusion (alignment versus size) and also because it has been studied extensively with both the inspection-trials (e.g., Beckett, 1989;Predebon, 1990) and the repeated-trials (Day, 1962;MacKay & Newbigging, 1977) decrement paradigms.…”

Section: Discussionmentioning

confidence: 99%

“…Illusion decrement has been used mainly as a tool for identifying and estimating the relative contributions of the factors contributing to a given perceptual distortion (see Beckett, 1989;Coren & Girgus, 1978, for discussions). The experiments described below, however, investigated aspects of the decrement effect itself with particular reference to claims (Schiano & Jordan, 1990;Watson et al, 1991) that sheer practice or repeatedjudgment and not prolonged inspection of the illusion figure is the primary determinant of decrement.…”

Section: Introductionmentioning

confidence: 99%

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Decrement of the Müller-Lyer and Poggendorff illusions: the effects of inspection and practice

Predebon

2005

Psychological Research

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Five experiments assessed the decline or decrement in illusion magnitude for the wings-out form and the combined or Brentano form of the Müller-Lyer illusion, and for the Poggendorff illusion. Judgments were obtained under conditions of either continuous or intermittent inspection of the illusion figure. In the continuous-inspection conditions observers scanned the illusion figure during the inter-trial intervals whereas in the intermittent-inspection conditions they did not. Substantial illusion decrement was found in all continuous-inspection conditions and in intermittent conditions with short inter-trial intervals (upto 20 s) but not with longer inter-trial intervals. However, intermittent-inspection with a long inter-trial interval (40 s) produced illusion decrement but only when observers were instructed during the decrement session to ignore the wings, and pay attention to the shaft, of the Müller-Lyer figure. Taken together, the pattern of results does not support the claim that illusion decrement is primarily a product of practice or repeated trials.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Decrement of the Müller-Lyer and Poggendorff illusions: the effects of inspection and practice

Predebon

2005

Psychological Research

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“…In lieu of angle effects, the role of lineorientation processing could still be demonstrated by the persistence of the illusion when the figure is presented through stereopsis (Drobnis & Lawson, 1976;Gyoba, 1978;Schiller & Wiener, 1962). A similar argument could be made in terms of a robust effect being seen when the illusion is produced through illusory contours (Beckett, 1989(Beckett, , 1990Day et al, 1977;Shen et al, 2016;Spoto et al, 2008;Tibber et al, 2008). In both cases, no angle is presented in the stimuli yet an illusion is still reported.…”

Section: Discussionmentioning

confidence: 90%

The role of line-orientation processing in the production of the Poggendorff illusion: A dual-task study

Harris

Yildiz

Chouinard

2023

Atten Percept Psychophys

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Using a dual-task paradigm, the present investigation examined whether processes related to line orientation play a critical role in the production of the Poggendorff illusion. In Experiment 1 , we assessed the magnitude of the Poggendorff illusion under three different task conditions. In the single-task condition, participants were asked to report how they perceive the alignment of transversal lines in the Poggendorff figure. In two different dual-task conditions, the participants were asked to read aloud the time displayed on a digital or analogue clock while also performing the Poggendorff perception task. The method of constant stimuli was used to calculate the point of subjective equality (PSE) and bistability width values, which represent illusion strength and perceptual uncertainty, respectively. PSEs indicated that the magnitude of the illusion did not vary between single, dual-analogue, and dual-digital task conditions, which suggests that the additional demands placed by the dual tasks had no effect on the illusion strength. Perceptual uncertainty and clock-reading errors were greater in the dual-analogue task condition. Experiment 2 revealed that the analogue clockface was more difficult to read than the digital clockface. Based on these results, we conclude that having participants perform a secondary task does not influence the magnitude of the Poggendorff illusion.

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“…If the parallel lines in a Poggendorff figure are replaced with subjective contours, the effect would seem to persist 20. This may be true of subjective contours defined by Kanizsa-like Pac-Man tokens,20 luminance steps, texture borders,21 and complex composite images that define the parallels through “good continuation” or “closure.”22 However, in many of these studies, interpretation of the results is complicated by the absence of quantitative measures of effect size, a lack of statistical tests of significance, or a failure to include the appropriate controls and measures of baseline biases 20,21,23-25. To demonstrate that subjective contours are truly driving the Poggendorff effect, the baseline bias (the degree of misalignment perceived between two transversal lines in the absence of further context) must first be subtracted from the overall bias.…”

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confidence: 99%

Biases and Sensitivities in the Poggendorff Effect when Driven by Subjective Contours

Tibber

Melmoth

Morgan

2008

Invest. Ophthalmol. Vis. Sci.

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Purpose-A consensus in the existing literature suggests that the Poggendorff effect (a perceptual misalignment of two collinear transversal segments when separated by a pair of parallel contours) persists when the parallels are defined by Kanizsa-like subjective contours. However, previous studies have often been complicated by a lack of quantitative measures of effect size, statistical tests of significance, appropriate measures of baseline and control biases, or stringent definition of subjective contours. The aim of this study was thus to determine whether subjective contours are capable of driving the Poggendorff effect once other factors are accounted for.Methods-Twenty participants were tested on a number of test and control figures incorporating first-order (luminance-defined) and subjective parallels using the method of adjustment. All figures were tested at two different orientations, and observer sensitivities and observer biases were assessed.Results-A systematic response bias (in the direction of the classical effect) was found for Poggendorff figures that incorporated subjective parallels. The effect was highly significant and greater than for control figures. There was no concomitant change in judgment sensitivity (positional certainty). Finally, there was a positive correlation between the effect size for figures incorporating first-order and subjective parallels. Conclusions-The findings reported demonstrate conclusively that true Kanizsa-like subjective contours are capable of driving the Poggendorff effect. Further, the data are consistent with a growing body of evidence that suggests both first-order and subjective contours are processed at early loci in the visual pathways when position is encoded.The Poggendorff effect (1860) is a well-documented geometric illusion in which there is a perceptual misalignment of two collinear oblique lines when separated by a pair of parallel contours (henceforth referred to as the transversals and parallels respectively; see Fig. 1A). Several explanations have been put forward to account for the effect, including a misestimation of the orientation of the transversals through lateral inhibition, obtuse angle contraction, or angular induction,1-5 a bowing of the transversals at points of intersection with the parallels,6 a misestimation of the orientation of a projected line connecting the transversals as a result of neural blurring,7,8 a perceptual contraction or expansion of the space between the parallels,9-11 a misinterpretation of the transversals as receding in depth,

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Illusion decrement and transfer of illusion decrement in real- and subjective-contour Poggendorff figures

Cited by 20 publications

References 41 publications

Decrement of the Müller-Lyer and Poggendorff illusions: the effects of inspection and practice

Decrement of the Müller-Lyer and Poggendorff illusions: the effects of inspection and practice

The role of line-orientation processing in the production of the Poggendorff illusion: A dual-task study

Biases and Sensitivities in the Poggendorff Effect when Driven by Subjective Contours

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