Mather, George and Daniell, A. K. (2005) No effect of spatial phase randomisation on direction discrimination in dense random element patterns. Vision Research, 45 (6). pp. 759-764. ISSN 0042-6989

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Abstract

Two computational strategies have been proposed for motion analysis in the human visual system. Energy-based schemes involve detection of spatiotemporal Fourier energyin the frequencycomponents comprising a moving pattern. Edge-based schemes track shifts in the position of local edges in the pattern over time. This paper describes a stimulus manipulation, spatial phase randomisation, that acts as a diagnostic test for the involvement of energy-based processes, and describes the results of two experiments which applythe manipulation to random element patterns. Both experiments compared direction discrimination performance in patterns before and after the spatial phase of their components was randomised in the Fourier domain. For dense patterns, there was no effect of phase randomisation on the maximum displacement supporting reliable direction discrimination, indicating that energy-based responses were dominant. For sparse patterns, a significant effect of phase randomisation was obtained, indicating a greater role for edge-based responses.

Item Type:	Article
Additional Information:	Two computational strategies have been proposed for motion analysis in the human visual system. Energy-based schemes involve detection of spatiotemporal Fourier energyin the frequencycomponents comprising a moving pattern. Edge-based schemes track shifts in the position of local edges in the pattern over time. This paper describes a stimulus manipulation, spatial phase randomisation, that acts as a diagnostic test for the involvement of energy-based processes, and describes the results of two experiments which applythe manipulation to random element patterns. Both experiments compared direction discrimination performance in patterns before and after the spatial phase of their components was randomised in the Fourier domain. For dense patterns, there was no effect of phase randomisation on the maximum displacement supporting reliable direction discrimination, indicating that energy-based responses were dominant. For sparse patterns, a significant effect of phase randomisation was obtained, indicating a greater role for edge-based responses.
Keywords:	spatial phase randomisation, direction discrimination
Subjects:	C Biological Sciences > C800 Psychology C Biological Sciences > C850 Cognitive Psychology
Divisions:	College of Social Sciences > Faculty of Health & Social Sciences > School of Psychology
Depositing User:	Alison Wilson
Date Deposited:	13 Oct 2011 12:32
Last Modified:	13 Mar 2013 09:02
URI:	http://eprints.lincoln.ac.uk/id/eprint/4738

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