July 2013
Volume 13, Issue 9
Vision Sciences Society Annual Meeting Abstract  |   July 2013
Enumeration of Illusory Contour Figures
Author Affiliations
  • Natasha Dienes
    Department of Psychology, University of Guelph
  • Lana Trick
    Department of Psychology, University of Guelph
Journal of Vision July 2013, Vol.13, 432. doi:https://doi.org/10.1167/13.9.432
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      Natasha Dienes, Lana Trick; Enumeration of Illusory Contour Figures. Journal of Vision 2013;13(9):432. doi: https://doi.org/10.1167/13.9.432.

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

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Every day we encounter objects that are partially obscured by shadows or other objects. We can study how our visual system processes these items by creating objects which do not have a real contour (i.e., a solid line) completely surrounding them. This project used enumeration (determining the number of objects present) to study the way that illusory contour figures are processed. The processing of illusory contour objects has previously been studied using a visual search task (Li, Cave & Wolfe, 2008). Li, et al. (2008) found that line-end illusory contour figures (figures that are induced through the particular way lines end around the "object") pop out in visual search. Because objects that pop out in search are usually subitized (fast, accurate and effortless enumeration of a small quantity of objects), it was hypothesized that line-end illusory contour figures would be subitized both when they were presented only as targets (simple enumeration task) and when they were presented with distractors (selective enumeration task). The simple enumeration task required participants to enumerate 1-9 vertical line-end illusory contour rectangles or real contour rectangles presented in conjunction with the line-end inducers. The selective enumeration task was the same expect for the addition of 4 or 8 horizontal distractors of the same figure type. The results of these two enumeration tasks revealed that line-end illusory contour figures can be subitized when they are presented alone, but not when they are presented with distractors. These results may be due to differences in task demands which can be explained by Pylyshyn’s (1988) FINST theory.

Meeting abstract presented at VSS 2013


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