Subjective criteria and illusions in visual testing: some methodological limitations

Skottun, Bernt C.; Skoyles, John R.

doi:10.1007/s00426-013-0482-z

Cited by 14 publications

(13 citation statements)

References 25 publications

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“…However, it has been argued before that this kind of design is suboptimal for the purposes of measuring perception. A forced choice response involves mentally recreating subjective threshold criteria of size difference which the illusion must break before an illusion-supporting response is reported (Skottun & Skoyles, 2014). When making between-group comparisons, this may affect the validity of inferences made about the visual systems of those groups; such as patients with schizophrenia.…”

Section: Limitations In Previous Researchmentioning

confidence: 99%

“…Therefore, alternative measurements of perceptual judgment such as manual estimations, adjustments and match-to-sample tasks, could be used instead to try and reduce the confounding nature that previous forced-response tasks may have introduced in visual illusion research. However, a more general critique of the use of visual illusions in studying perception has been offered in the literature (Skottun & Skoyles, 2014): as illusions are necessarily based on subjective criteria, when comparing performance in two groups (i.e. patent vs. control group), one cannot be certain whether differences in susceptibility reflect differences in the response criteria or differences in the underlying sensory process, making it difficult, if not impossible, to apply criterion-independent tests.…”

Section: Limitations In Previous Researchmentioning

confidence: 99%

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A review of abnormalities in the perception of visual illusions in schizophrenia

et al. 2016

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Specific abnormalities of vision in schizophrenia have been observed to affect high-level and some low-level integration mechanisms, suggesting that people with schizophrenia may experience anomalies across different stages in the visual system affecting either early or late processing or both. Here, we review the research into visual illusion perception in schizophrenia and the issues which previous research has faced. One general finding that emerged from the literature is that those with schizophrenia are mostly immune to the effects of high-level illusory displays, but this effect is not consistent across all low-level illusions. The present review suggests that this resistance is due to the weakening of top–down perceptual mechanisms and may be relevant to the understanding of symptoms of visual distortion rather than hallucinations as previously thought.

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Section: Limitations In Previous Researchmentioning

confidence: 99%

Section: Limitations In Previous Researchmentioning

confidence: 99%

A review of abnormalities in the perception of visual illusions in schizophrenia

et al. 2016

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“…All previous studies assessing visual illusions in autism have confounded the observer’s sensitivity to an illusion with the observer’s subjective criterion for reporting whether the illusion was seen [29, 30]. Therefore, group differences in responses to illusions may have arisen due to differences in subjective criteria—or decisional bias, without necessitating underlying differences in perception: a possibility that is particularly likely when groups may differ according to cognitive and affective factors [30]. 1 Indeed, the problem of distinguishing a perceptual from a cognitive bias is not confined to studies of autism, but applies to all Type 2 psychophysical measures of bias [29] such as visual after-effects [31, 32].…”

Section: Introductionmentioning

confidence: 99%

Susceptibility to Ebbinghaus and Müller-Lyer illusions in autistic children: a comparison of three different methods

et al. 2017

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BackgroundStudies reporting altered susceptibility to visual illusions in autistic individuals compared to that typically developing individuals have been taken to reflect differences in perception (e.g. reduced global processing), but could instead reflect differences in higher-level decision-making strategies.MethodsWe measured susceptibility to two contextual illusions (Ebbinghaus, Müller-Lyer) in autistic children aged 6–14 years and typically developing children matched in age and non-verbal ability using three methods. In experiment 1, we used a new two-alternative-forced-choice method with a roving pedestal designed to minimise cognitive biases. Here, children judged which of two comparison stimuli was most similar in size to a reference stimulus. In experiments 2 and 3, we used methods previously used with autistic populations. In experiment 2, children judged whether stimuli were the ‘same’ or ‘different’, and in experiment 3, we used a method-of-adjustment task.ResultsAcross all tasks, autistic children were equally susceptible to the Ebbinghaus illusion as typically developing children. Autistic children showed a heightened susceptibility to the Müller-Lyer illusion, but only in the method-of-adjustment task. This result may reflect differences in decisional criteria.ConclusionsOur results are inconsistent with theories proposing reduced contextual integration in autism and suggest that previous reports of altered susceptibility to illusions may arise from differences in decision-making, rather than differences in perception per se. Our findings help to elucidate the underlying reasons for atypical responses to perceptual illusions in autism and call for the use of methods that reduce cognitive bias when measuring illusion susceptibility.Electronic supplementary materialThe online version of this article (doi:10.1186/s13229-017-0127-y) contains supplementary material, which is available to authorized users.

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“…The present study filled this gap via a survey of face perception quality in everyday life. Compared to an experimentally-determined assessment of face identity discrimination, self-report based assessment is subjective and may potentially be influenced by individual biases (Chen, Palafox et al 1999; Skottun and Skoyles 2014), such as biasing to report more negatively about observations and experiences. Inclusion of reporting both negative and positive responses in self-report assessment may help to overcome this issue.…”

Section: Discussionmentioning

confidence: 99%

Perception of faces in schizophrenia: Subjective (self-report) vs. objective (psychophysics) assessments

Chen

Ekstrom

2016

Journal of Psychiatric Research

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Objectives Face perception impairment in schizophrenia has been demonstrated, mostly through experimental studies. How this laboratory-defined behavioral impairment is associated with patients’ perceptual experience of various faces in everyday life is however unclear. This question is important because a first-person account of face perception has direct consequences on social functioning of patients. In this study, we adapted and administered a self-reported questionnaire on narrative perceptual experience of faces along with psychophysical assessments of face perception in schizophrenia. Methods The self-reported questionnaire includes six rating items of face-related functioning in everyday life, providing a subjective measure of face perception. The psychophysical assessment determines perceptual threshold for discriminating different facial identities, providing an objective measure of face perception. Results Compared to controls (n=25), patients (n=35) showed significantly lower scores (worse performance) in the subjective assessment and significantly higher thresholds (worse performance) in the objective assessment. The subjective and objective face perception assessments were moderately correlated in controls but not in patients. The subjective face perception assessments were significantly correlated with measurements of a social cognitive ability (Theory of Mind), again in controls but not in patients. Conclusion These results suggest that in schizophrenia the quality of face-related functioning in everyday life is degraded and the role that basic face discrimination capacity plays in face-related everyday functioning is disrupted.

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Subjective criteria and illusions in visual testing: some methodological limitations

Cited by 14 publications

References 25 publications

A review of abnormalities in the perception of visual illusions in schizophrenia

A review of abnormalities in the perception of visual illusions in schizophrenia

Susceptibility to Ebbinghaus and Müller-Lyer illusions in autistic children: a comparison of three different methods

Perception of faces in schizophrenia: Subjective (self-report) vs. objective (psychophysics) assessments

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