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Conference Paper: Crowding without visual awareness

TitleCrowding without visual awareness
Authors
Issue Date2009
Citation
The 2009 Annual Meeting of the Vision Sciences Society (VSS 2009), Naples, FL., 8-13 May 2009. In Journal of Vision, 2009, v. 9 n. 8, p. 991 How to Cite?
AbstractPURPOSE: Visual crowding refers to the impaired identification of a peripheral stimulus when it is surrounded by flankers with similar patterns. According to an attention explanation, crowding happens because attention fails to individualize the target among the flankers due to limited spatial resolution of attention. As voluntary attentional selection requires visual awareness, here we ask whether visual awareness is necessary for crowding to happen. METHOD: Two normally sighted observers adapted to a dicoptic stimulus located at 25° in the lower visual field for 5 s. The non-dominant eye was shown a low-contrast (×16 of the detection contrast threshold) Gabor target (oriented at 45°) with or without 4 Gabor flankers (oriented at 45° or −45°). The observers were unaware of the target and flankers because the percept was always dominated by a series of chromatic dynamic noise presented to the dominant eye. Contrast threshold at the retinal location of the target was measured by a 2IFC detection task. Threshold elevation was calculated by comparing thresholds with and without adaptation, and was measured in both crowded and isolated conditions. RESULTS: Threshold elevation was found only when the target and test had the same orientation. Threshold elevation in the crowded condition was 31 +/− 6% lower than the control condition. CONCLUSIONS: The magnitude of orientation-specific adaptation was reduced in the presence of flankers, even though the observers were unaware of neither the target nor the flankers. Thus, crowding happens without visual awareness. Our findings challenge the role of voluntary attention in crowding.
Persistent Identifierhttp://hdl.handle.net/10722/63129

 

DC FieldValueLanguage
dc.contributor.authorCham, SLen_HK
dc.contributor.authorCheung, SHen_HK
dc.date.accessioned2010-07-13T04:16:42Z-
dc.date.available2010-07-13T04:16:42Z-
dc.date.issued2009en_HK
dc.identifier.citationThe 2009 Annual Meeting of the Vision Sciences Society (VSS 2009), Naples, FL., 8-13 May 2009. In Journal of Vision, 2009, v. 9 n. 8, p. 991-
dc.identifier.urihttp://hdl.handle.net/10722/63129-
dc.description.abstractPURPOSE: Visual crowding refers to the impaired identification of a peripheral stimulus when it is surrounded by flankers with similar patterns. According to an attention explanation, crowding happens because attention fails to individualize the target among the flankers due to limited spatial resolution of attention. As voluntary attentional selection requires visual awareness, here we ask whether visual awareness is necessary for crowding to happen. METHOD: Two normally sighted observers adapted to a dicoptic stimulus located at 25° in the lower visual field for 5 s. The non-dominant eye was shown a low-contrast (×16 of the detection contrast threshold) Gabor target (oriented at 45°) with or without 4 Gabor flankers (oriented at 45° or −45°). The observers were unaware of the target and flankers because the percept was always dominated by a series of chromatic dynamic noise presented to the dominant eye. Contrast threshold at the retinal location of the target was measured by a 2IFC detection task. Threshold elevation was calculated by comparing thresholds with and without adaptation, and was measured in both crowded and isolated conditions. RESULTS: Threshold elevation was found only when the target and test had the same orientation. Threshold elevation in the crowded condition was 31 +/− 6% lower than the control condition. CONCLUSIONS: The magnitude of orientation-specific adaptation was reduced in the presence of flankers, even though the observers were unaware of neither the target nor the flankers. Thus, crowding happens without visual awareness. Our findings challenge the role of voluntary attention in crowding.-
dc.languageengen_HK
dc.relation.ispartofJournal of Vision-
dc.titleCrowding without visual awarenessen_HK
dc.typeConference_Paperen_HK
dc.identifier.emailCham, SL: joeycham@gmail.comen_HK
dc.identifier.emailCheung, SH: singhang@hku.hken_HK
dc.identifier.authorityCheung, SH=rp00590en_HK
dc.description.naturelink_to_OA_fulltext-
dc.identifier.doi10.1167/9.8.991-
dc.identifier.hkuros155413en_HK
dc.identifier.volume9-
dc.identifier.issue8-
dc.identifier.spage991-
dc.identifier.epage991-
dc.customcontrol.immutablesml 160212-

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