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Kavšek M. Perception of illusory contours in children and adults: An eye-tracking study. Atten Percept Psychophys 2023:10.3758/s13414-023-02832-z. [PMID: 38157202 DOI: 10.3758/s13414-023-02832-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2023] [Indexed: 01/03/2024]
Abstract
The eye-tracking study investigated the perception of subjective Kanizsa and Ehrenstein figures in adults and in children aged 3-4, 5-6, 7-8, and 9-11 years of age. More specifically, the distribution of looking at the inner stimulus part versus the inducing elements was measured for illusory figures, figures with real contours, and control displays. It was hypothesized that longer looking at the inner area of the illusory figures indicates global contour interpolation, whereas longer looking at the inducing elements indicates a local processing mode. According to the results, participants of all ages looked longer at the illusory Kanizsa and Ehrenstein contours than at the figures' inducing elements. However, performance was lowest in the children aged 3-4 years and increased during the preschool period. Moreover, the illusory contour displays elicited comparable visual responses as did the real contour displays. The use of the control displays that contained no contour information ensured that the participants' looking behavior was not driven by a spontaneous tendency to attend to the inner stimulus parts. The study confirms the view that sensitivity to illusory contours emerges very early in life.
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Affiliation(s)
- Michael Kavšek
- Department of Psychology, University of Bonn, Kaiser-Karl-Ring 9, 53111, Bonn, Germany.
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Yan C, Pérez-Bellido A, de Lange FP. Amodal completion instead of predictive coding can explain activity suppression of early visual cortex during illusory shape perception. J Vis 2021; 21:13. [PMID: 33988675 PMCID: PMC8131992 DOI: 10.1167/jov.21.5.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
A set of recent neuroimaging studies observed that the perception of an illusory shape can elicit both positive and negative feedback modulations in different parts of the early visual cortex. When three Pac-Men shapes were aligned in such a way that they created an illusory triangle (i.e., the Kanizsa illusion), neural activity in early visual cortex was enhanced in those neurons that had receptive fields that overlapped with the illusory shape but suppressed in neurons whose receptive field overlapped with the Pac-Men inducers. These results were interpreted as congruent with the predictive coding framework, in which neurons in early visual cortex enhance or suppress their activity depending on whether the top-down predictions match the bottom-up sensory inputs. However, there are several plausible alternative explanations for the activity modulations. Here we tested a recent proposal (Moors, 2015) that the activity suppression in early visual cortex during illusory shape perception reflects neural adaptation to perceptually stable input. Namely, the inducers appear perceptually stable during the illusory shape condition (discs on which a triangle is superimposed), but not during the control condition (discs that change into Pac-Men). We examined this hypothesis by manipulating the perceptual stability of inducers. When the inducers could be perceptually interpreted as persistent circles, we replicated the up- and downregulation pattern shown in previous studies. However, when the inducers could not be perceived as persistent circles, we still observed enhanced activity in neurons representing the illusory shape but the suppression of activity in neurons representing the inducers was absent. Thus our results support the hypothesis that the activity suppression in neurons representing the inducers during the Kanizsa illusion is better explained by neural adaptation to perceptually stable input than by reduced prediction error.
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Affiliation(s)
- Chuyao Yan
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, the Netherlands.,
| | - Alexis Pérez-Bellido
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, the Netherlands.,Department of Cognition, Development and Educational Psychology, University of Barcelona, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain.,
| | - Floris P de Lange
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, the Netherlands.,
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Tivadar RI, Gaglianese A, Murray MM. Auditory Enhancement of Illusory Contour Perception. Multisens Res 2020; 34:1-15. [PMID: 33706283 DOI: 10.1163/22134808-bja10018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 04/24/2020] [Indexed: 11/19/2022]
Abstract
Illusory contours (ICs) are borders that are perceived in the absence of contrast gradients. Until recently, IC processes were considered exclusively visual in nature and presumed to be unaffected by information from other senses. Electrophysiological data in humans indicates that sounds can enhance IC processes. Despite cross-modal enhancement being observed at the neurophysiological level, to date there is no evidence of direct amplification of behavioural performance in IC processing by sounds. We addressed this knowledge gap. Healthy adults ( n = 15) discriminated instances when inducers were arranged to form an IC from instances when no IC was formed (NC). Inducers were low-constrast and masked, and there was continuous background acoustic noise throughout a block of trials. On half of the trials, i.e., independently of IC vs NC, a 1000-Hz tone was presented synchronously with the inducer stimuli. Sound presence improved the accuracy of indicating when an IC was presented, but had no impact on performance with NC stimuli (significant IC presence/absence × Sound presence/absence interaction). There was no evidence that this was due to general alerting or to a speed-accuracy trade-off (no main effect of sound presence on accuracy rates and no comparable significant interaction on reaction times). Moreover, sound presence increased sensitivity and reduced bias on the IC vs NC discrimination task. These results demonstrate that multisensory processes augment mid-level visual functions, exemplified by IC processes. Aside from the impact on neurobiological and computational models of vision, our findings may prove clinically beneficial for low-vision or sight-restored patients.
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Affiliation(s)
- Ruxandra I Tivadar
- 1The LINE (Laboratory for Investigative Neurophysiology), Department of Radiology, University Hospital CenterandUniversity of Lausanne, 1011 Lausanne, Switzerland.,2Department of Ophthalmology, University of LausanneandFondation Asile des aveugles, Lausanne, Switzerland
| | - Anna Gaglianese
- 1The LINE (Laboratory for Investigative Neurophysiology), Department of Radiology, University Hospital CenterandUniversity of Lausanne, 1011 Lausanne, Switzerland.,3Spinoza Centre for Neuroimaging, Amsterdam, The Netherlands
| | - Micah M Murray
- 1The LINE (Laboratory for Investigative Neurophysiology), Department of Radiology, University Hospital CenterandUniversity of Lausanne, 1011 Lausanne, Switzerland.,2Department of Ophthalmology, University of LausanneandFondation Asile des aveugles, Lausanne, Switzerland.,4Sensory, Perceptual and Cognitive Neuroscience Section, Center for Biomedical Imaging (CIBM), University Hospital CenterandUniversity of Lausanne, 1011 Lausanne, Switzerland.,5Department of Hearing and Speech Sciences, Vanderbilt University, Nashville, TN, USA
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