Visual repetition facilitates the detection of Gaborized shape outlines C Gillespie, D Vishwanath |
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Psychology and Neuroscience, University of St Andrews, United Kingdom
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| Repetition underlies important aspects of visual perception such the recognition of patterns, object grouping and pictorial sequences (e.g., film reels/cartoon strips). These contain spatially separated shapes which have perceptual relationships with each other. Such shapes may appear as being instances of different objects, or alternatively as distinct instances of the same object. How do spatially distinct but repeating images of objects visually interact with each other, and yield such different perceptual effects? To begin to answer this question, the effect of shape repetition on detection of shape outlines was examined. A set of Gaborized outlines (animate, inanimate, geometric shapes, etc.) were embedded in backgrounds of randomly orientated Gabor patches. Four conditions were presented to participants with flanker outline shapes on either side of the target outline (control, 0-X-0; triplet, X-X-X; flanking doublet, Y-X-Y; unique, Y-X-Z). Discrimination thresholds for detecting the presence of an outline (2-AFC) were measured while varying the orientation noise of the contour Gabor elements (adaptive staircase). Repetitions of identical outline (triplet, X-X-X) produced significantly lower thresholds in comparison to all other conditions. The data further suggests that while the type of outline appears to have no significant effect on thresholds, specific inter-object similarities (symmetry) may be relevant. |
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