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Disparity-defined objects moving in depth do not elicit three-dimensional shape constancy

Scarfe, P and Hibbard, PB (2006) 'Disparity-defined objects moving in depth do not elicit three-dimensional shape constancy.' Vision Research, 46 (10). 1599 - 1610. ISSN 0042-6989


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Observers generally fail to recover three-dimensional shape accurately from binocular disparity. Typically, depth is overestimated at near distances and underestimated at far distances [Johnston, E. B. (1991). Systematic distortions of shape from stereopsis. Vision Research, 31, 1351-1360]. A simple prediction from this is that disparity-defined objects should appear to expand in depth when moving towards the observer, and compress in depth when moving away. However, additional information is provided when an object moves from which 3D Euclidean shape can be recovered, be this through the addition of structure from motion information [Richards, W. (1985). Structure from stereo and motion. Journal of the Optical Society of America A, 2, 343-349] , or the use of non-generic strategies [Todd, J. T., & Norman, J. F. (2003). The visual perception of 3-D shape from multiple cues: Are observers capable of perceiving metric structure? Perception and Psychophysics, 65, 31-47]. Here, we investigated shape constancy for objects moving in depth. We found that to be perceived as constant in shape, objects needed to contract in depth when moving toward the observer, and expand in depth when moving away, countering the effects of incorrect distance scaling (Johnston, 1991). This is a striking example of the failure of shape constancy, but one that is predicted if observers neither accurately estimate object distance in order to recover Euclidean shape, nor are able to base their responses on a simpler processing strategy. © 2005 Elsevier Ltd. All rights reserved.

Item Type: Article
Subjects: B Philosophy. Psychology. Religion > BF Psychology
Divisions: Faculty of Science and Health > Psychology, Department of
Depositing User: Users 161 not found.
Date Deposited: 13 Feb 2015 21:31
Last Modified: 17 Aug 2017 17:41

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