The neural signature of the Fraser illusion: An explorative EEG study on Fraser-like displays

We studied neural correlates accompanying the Fraser spiral illusion. The Fraser spiral illusion consists of twisted cords superimposed on a patchwork background arranged in concentric circles, which is typically perceived as a spiral. We tested four displays: the Fraser spiral illusion and three va...

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Main Authors: Xuyan eYun, Simon J. eHazenberg, Richard H.A.H. eJacobs, Jiang eQiu, Rob evan Lier
Format: Article
Language:English
Published: Frontiers Media S.A. 2015-07-01
Series:Frontiers in Human Neuroscience
Subjects:
Online Access:http://journal.frontiersin.org/Journal/10.3389/fnhum.2015.00374/full
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author Xuyan eYun
Xuyan eYun
Xuyan eYun
Simon J. eHazenberg
Richard H.A.H. eJacobs
Jiang eQiu
Jiang eQiu
Rob evan Lier
author_facet Xuyan eYun
Xuyan eYun
Xuyan eYun
Simon J. eHazenberg
Richard H.A.H. eJacobs
Jiang eQiu
Jiang eQiu
Rob evan Lier
author_sort Xuyan eYun
collection DOAJ
description We studied neural correlates accompanying the Fraser spiral illusion. The Fraser spiral illusion consists of twisted cords superimposed on a patchwork background arranged in concentric circles, which is typically perceived as a spiral. We tested four displays: the Fraser spiral illusion and three variants derived from it by orthogonally combining featural properties. In our stimuli, the shape of the cords comprised either concentric circles or a single spiral. The cords themselves consisted of black and white lines in parallel to the contour of the cords (i.e. parallel cords), or oblique line elements (i.e. twisted cords). The displays with twisted cords successfully induced illusory percepts, i.e. circles looked like spirals (the Fraser spiral illusion) and spirals looked like circles (i.e., a ‘reverse Fraser illusion’). We compared the event-related potentials in a Stimulus (Circle, Spiral) × Percept (Circle, Spiral) design. A significant main effect of Stimulus was found at the posterior scalp in an early component (P220-280) and a significant main effect of Percept was found over the anterior scalp in a later component (P350-450). Although the EEG data suggest stimulus-based processing in posterior area in an early time window and Percept based processing in the later time window, an overall clear-cut stimulus-percept segregation was not found due to additional interaction effects. Instead, the data, especially in the later time window in the anterior area, point at differential processing for the condition comprising circle shapes but spiral percepts (i.e. the Fraser illusion).
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spelling doaj.art-0a1afbea0ea6486fba02e88cd98f5dbc2022-12-22T01:32:24ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612015-07-01910.3389/fnhum.2015.00374122938The neural signature of the Fraser illusion: An explorative EEG study on Fraser-like displaysXuyan eYun0Xuyan eYun1Xuyan eYun2Simon J. eHazenberg3Richard H.A.H. eJacobs4Jiang eQiu5Jiang eQiu6Rob evan Lier7Radboud University, Donders Institute for Brain, Cognition and BehaviourSouthwest University (SWU)Key laboratory of cognition and personality (SWU), Ministry of EducationRadboud University, Donders Institute for Brain, Cognition and BehaviourRadboud University, Donders Institute for Brain, Cognition and BehaviourSouthwest University (SWU)Key laboratory of cognition and personality (SWU), Ministry of EducationRadboud University, Donders Institute for Brain, Cognition and BehaviourWe studied neural correlates accompanying the Fraser spiral illusion. The Fraser spiral illusion consists of twisted cords superimposed on a patchwork background arranged in concentric circles, which is typically perceived as a spiral. We tested four displays: the Fraser spiral illusion and three variants derived from it by orthogonally combining featural properties. In our stimuli, the shape of the cords comprised either concentric circles or a single spiral. The cords themselves consisted of black and white lines in parallel to the contour of the cords (i.e. parallel cords), or oblique line elements (i.e. twisted cords). The displays with twisted cords successfully induced illusory percepts, i.e. circles looked like spirals (the Fraser spiral illusion) and spirals looked like circles (i.e., a ‘reverse Fraser illusion’). We compared the event-related potentials in a Stimulus (Circle, Spiral) × Percept (Circle, Spiral) design. A significant main effect of Stimulus was found at the posterior scalp in an early component (P220-280) and a significant main effect of Percept was found over the anterior scalp in a later component (P350-450). Although the EEG data suggest stimulus-based processing in posterior area in an early time window and Percept based processing in the later time window, an overall clear-cut stimulus-percept segregation was not found due to additional interaction effects. Instead, the data, especially in the later time window in the anterior area, point at differential processing for the condition comprising circle shapes but spiral percepts (i.e. the Fraser illusion).http://journal.frontiersin.org/Journal/10.3389/fnhum.2015.00374/fullComplexityIllusionevent-related potentials (ERPs)Shape PerceptionFraser spiral illusion
spellingShingle Xuyan eYun
Xuyan eYun
Xuyan eYun
Simon J. eHazenberg
Richard H.A.H. eJacobs
Jiang eQiu
Jiang eQiu
Rob evan Lier
The neural signature of the Fraser illusion: An explorative EEG study on Fraser-like displays
Frontiers in Human Neuroscience
Complexity
Illusion
event-related potentials (ERPs)
Shape Perception
Fraser spiral illusion
title The neural signature of the Fraser illusion: An explorative EEG study on Fraser-like displays
title_full The neural signature of the Fraser illusion: An explorative EEG study on Fraser-like displays
title_fullStr The neural signature of the Fraser illusion: An explorative EEG study on Fraser-like displays
title_full_unstemmed The neural signature of the Fraser illusion: An explorative EEG study on Fraser-like displays
title_short The neural signature of the Fraser illusion: An explorative EEG study on Fraser-like displays
title_sort neural signature of the fraser illusion an explorative eeg study on fraser like displays
topic Complexity
Illusion
event-related potentials (ERPs)
Shape Perception
Fraser spiral illusion
url http://journal.frontiersin.org/Journal/10.3389/fnhum.2015.00374/full
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