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dc.contributor.authorSchmidtmann, G
dc.contributor.authorOuhnana, M
dc.contributor.authorLoffler, G
dc.contributor.authorKingdom, FAA
dc.date.accessioned2017-11-16T17:34:36Z
dc.date.available2017-11-16T17:34:36Z
dc.date.issued2016-04
dc.identifier.issn0042-6989
dc.identifier.issn1878-5646
dc.identifier.urihttp://hdl.handle.net/10026.1/10189
dc.description.abstract

An essential part of visual object recognition is the evaluation of the curvature of both an object's outline as well as the contours on its surface. We studied a striking illusion of visual curvature--the arc-size illusion (ASI)--to gain insight into the visual coding of curvature. In the ASI, short arcs are perceived as flatter (less curved) compared to longer arcs of the same radius. We investigated if and how the ASI depends on (i) the physical size of the stimulus and (ii) on the length of the arc. Our results show that perceived curvature monotonically increases with arc length up to an arc angle of about 60°, thereafter remaining constant and equal to the perceived curvature of a full circle. We investigated if the misjudgment of curvature in the ASI translates into predictable biases for three other perceptual tasks: (i) judging the position of the centre of circular arcs; (ii) judging if two circular arcs fall on the circumference of the same (invisible) circle and (iii) interpolating the position of a point on the circumference of a circle defined by two circular arcs. We found that the biases in all the above tasks were reliably predicted by the same bias mediating the ASI. We present a simple model, based on the central angle subtended by an arc, that captures the data for all tasks. Importantly, we argue that the ASI and related biases are a consequence of the fact that an object's curvature is perceived as constant with viewing distance, in other words is perceptually scale invariant.

dc.format.extent50-56
dc.format.mediumPrint-Electronic
dc.languageen
dc.language.isoeng
dc.publisherElsevier BV
dc.subjectArc-size illusion
dc.subjectCurvature
dc.subjectCurvature misjudgment
dc.subjectCurvature constancy
dc.subjectScale invariance
dc.titleImagining circles – Empirical data and a perceptual model for the arc-size illusion
dc.typejournal-article
dc.typeArticle
plymouth.author-urlhttps://www.ncbi.nlm.nih.gov/pubmed/26902729
plymouth.volume121
plymouth.publisher-urlhttp://dx.doi.org/10.1016/j.visres.2015.12.003
plymouth.publication-statusPublished
plymouth.journalVision Research
dc.identifier.doi10.1016/j.visres.2015.12.003
plymouth.organisational-group/Plymouth
plymouth.organisational-group/Plymouth/Faculty of Health
plymouth.organisational-group/Plymouth/REF 2021 Researchers by UoA
plymouth.organisational-group/Plymouth/REF 2021 Researchers by UoA/UoA03 Allied Health Professions, Dentistry, Nursing and Pharmacy
plymouth.organisational-group/Plymouth/Research Groups
plymouth.organisational-group/Plymouth/Research Groups/Institute of Health and Community
plymouth.organisational-group/Plymouth/Users by role
plymouth.organisational-group/Plymouth/Users by role/Academics
dc.publisher.placeEngland
dcterms.dateAccepted2015-12-20
dc.identifier.eissn1878-5646
dc.rights.embargoperiodNot known
rioxxterms.versionofrecord10.1016/j.visres.2015.12.003
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserved
rioxxterms.licenseref.startdate2016-04
rioxxterms.typeJournal Article/Review


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