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Jordan Lass, Patrick Bennett, Mary Peterson, Allison Sekuler; Reduced convexity context effects in elderly not attributable to reduced presumption of depth. Journal of Vision 2016;16(12):302. doi: 10.1167/16.12.302.
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© 2017 Association for Research in Vision and Ophthalmology.
Convexity cues bias perceptual organization when observers resolve competing figure-ground (FG) interpretations of a stimulus. Convex regions are increasingly likely to be perceived as figures as the number of alternating, convex and homogeneously-filled concave regions in the surround increases (Peterson & Salvagio, 2008), and this Convexity Context Effect (CCE) is reduced in healthy aging (Lass, et al., 2012; 2013). The age-related CCE reduction has been interpreted as evidence for reduced suppression in seniors. However, CCEs may require inferring depth in the stimulus (Goldreich & Peterson, 2012), so reduced CCEs in aging may result from decreased depth presumption. If so, additional depth cues should increase the CCE in older adults. We tested this hypothesis in 24 younger (M=20.0, SD=1.7 years) and 24 older (M=71.8, SD=6.1 years) observers using a method that induces depth perception in younger adults (Froyen, et al., 2013): We filled alternating regions of 8-region displays with light or dark texture, and added horizontal motion that produced texture accretion/deletion at the bounding edges of the concave and/or convex regions. Stimuli were presented for 250 ms, and observers reported whether the light or dark region(s) appeared to be in the foreground. We predicted that the addition of opposing motion to both region types simultaneously would increase the CCE in older adults. In both age groups, moving regions were more likely to be perceived as background: relative to the baseline static condition, P(convex=figure) increased when motion was added to concave regions and decreased when added to convex regions. Critically, the addition of motion to both concave and convex regions simultaneously did not increase the CCE in either age group, despite this condition leading to an increased sense of depth. These results are inconsistent with the hypothesis that reduced CCEs in the elderly result from reduced presumption of depth in these stimuli.
Meeting abstract presented at VSS 2016
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