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Updated: Jul 2, 2026

Motion-Acuity Test for Visual Field Acuity Measurement with Motion-Defined Shapes
Published on: February 23, 2024
Luminance and contrast cues are integrated in global shape detection with contours
1School of Psychology, The University of Western Australia, 35 Stirling Highway, Crawley 6009, WA, Australia. jason.bell@mail.mcgill.ca
Abstract:
Radial frequency (RF) contours can be used to represent the boundaries of natural objects, making them a useful stimulus with which to study shape processing. The current study used these contours to investigate whether luminance- and contrast-defined shape cues are combined in the detection of globally processed contours. A set of three experiments are presented. Experiment 1 shows that an RF contour defined by any one of positive or negative luminance contrast relative to background or second-order texture (contrast defined), is detected in accordance with a global pooling of local shape information. Experiment 2 uses a lateral masking paradigm to reveal interactions between global shapes defined by luminance of either polarity or a second-order contrast variation. Experiment 3 shows that an RF pattern defined by all three characteristics (positive, negative luminance polarity and contrast modulation) in nonoverlapping contour sections can still be assembled into a global shape. These findings indicate that at the level where RF contours are globally processed, luminance of either polarity- or contrast-defined shape information can be effectively combined.
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