July 2013
Volume 13, Issue 9
Free
Vision Sciences Society Annual Meeting Abstract  |   July 2013
Impairments in pre-semantic processing contribute to category-specific recognition deficits
Author Affiliations
  • Katrien Torfs
    Laboratory of Experimental Psychology, University of Leuven (KU Leuven)\nInstitute of Neuroscience, University of Louvain
  • Sven Panis
    Laboratory of Experimental Psychology, University of Leuven (KU Leuven)
  • Johan Wagemans
    Laboratory of Experimental Psychology, University of Leuven (KU Leuven)
  • Glyn W. Humphreys
    Department of Experimental Psychology, School of Psychology, University of Oxford
Journal of Vision July 2013, Vol.13, 668. doi:10.1167/13.9.668
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      Katrien Torfs, Sven Panis, Johan Wagemans, Glyn W. Humphreys; Impairments in pre-semantic processing contribute to category-specific recognition deficits. Journal of Vision 2013;13(9):668. doi: 10.1167/13.9.668.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Several accounts have been proposed to explain category-specific recognition deficits. One key theoretical question is whether category-specific deficits reflect semantic-level impairments or whether they can reflect impairments in pre-semantic processing. Here, we investigated how global shape information (particularly overall shape symmetry and complexity), and local contour information (particularly curvature) influence object identification in a patient with a category-specific deficit for natural objects (i.e., living things). We manipulated the quality of the visual representation of objects by fragmenting their outlines in a naming task. Two types of fragmentation were used: one with low curvature fragments, and one with high curvature fragments. We used a dynamic build-up paradigm with fragments increasing in length in 10 steps, and recorded the lowest presentation number (1 to 10) that resulted in correct naming. Using a dynamic build-up paradigm and survival analysis, we investigated the generation of representations of natural and manmade objects over time. We found that the patient’s deficit was modulated by the percentage of outline shown, local curvature information, and global shape properties such as symmetry. Our results indicate a deficit in the dynamic build-up of representations for natural objects relative to manmade objects, indicating that pre-semantic processing impairments can contribute to the neuropsychological deficit for natural objects.

Meeting abstract presented at VSS 2013

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