Perceptual asymmetries in greyscales: object-based versus space-based influences

Thomas, Nicole A., and Elias, Lorin J. (2012) Perceptual asymmetries in greyscales: object-based versus space-based influences. Cortex, 48 (5). pp. 553-562.

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Neurologically normal individuals exhibit leftward spatial biases, resulting from object- and space-based biases; however their relative contributions to the overall bias remain unknown. Relative position within the display has not often been considered, with similar spatial conditions being collapsed across. Study 1 used the greyscales task to investigate the influence of relative position and object- and space-based contributions. One image in each greyscale pair was shifted towards the left or the right. A leftward object-based bias moderated by a bias to the centre was expected. Results confirmed this as a left object-based bias occurred in the right visual field, where the left side of the greyscale pairs was located in the centre visual field. Further, only lower visual field images exhibited a significant left bias in the left visual field. The left bias was also stronger when images were partially overlapping in the right visual field, demonstrating the importance of examining proximity. The second study examined whether object-based biases were stronger when actual objects, with directional lighting biases, were used. Direction of luminosity was congruent or incongruent with spatial location. A stronger object-based bias emerged overall; however a leftward bias was seen in congruent conditions and a rightward bias was seen in incongruent conditions. In conditions with significant biases, the lower visual field image was chosen most often. Results show that object- and space-based biases both contribute; however stimulus type allows either space- or object-based biases to be stronger. A lower visual field bias also interacts with these biases, leading the left bias to be eliminated under certain conditions. The complex interaction occurring between frame of reference and visual field makes spatial location extremely important in determining the strength of the leftward bias.

Item ID: 52462
Item Type: Article (Research - C1)
ISSN: 1973-8102
Keywords: lateral biases; horizontal shift; vertical location; pseudoneglect; proximity
Funders: Natural Sciences and Engineering Research Council of Canada (NSERC)
Projects and Grants: NSERC fellowship
Date Deposited: 18 Jul 2018 05:03
FoR Codes: 17 PSYCHOLOGY AND COGNITIVE SCIENCES > 1701 Psychology > 170101 Biological Psychology (Neuropsychology, Psychopharmacology, Physiological Psychology) @ 50%
17 PSYCHOLOGY AND COGNITIVE SCIENCES > 1701 Psychology > 170112 Sensory Processes, Perception and Performance @ 50%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970117 Expanding Knowledge in Psychology and Cognitive Sciences @ 100%
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