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The Judd illusion: evidence for two visual streams or two experimental conditions?

Mon-Williams, M. and Bull, R. (2000) The Judd illusion: evidence for two visual streams or two experimental conditions? Experimental Brain Research, 130 (2). pp. 273-276. ISSN 0014-4819

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In the Judd illusion, observers inaccurately bisect the shaft located between two arrowheads pointing in the same direction. The magnitude of error is greater when verbal judgements are compared to action based responses (reaching out and grasping the centre of the bar). This difference has been attributed to the presence of two visual streams within cortical processing. In contrast, we provide evidence that the improved accuracy in the reaching condition may be due to occlusion of the illusory background during the transport phase of the movement. We suggest that caution is required when interpreting performance differences between two conditions that are not strictly equivalent.

Item Type: Article
Keywords: prehension; visual pathways; illusions; human; motor control
Institution: The University of Leeds
Academic Units: The University of Leeds > Faculty of Medicine and Health (Leeds) > School of Psychology (Leeds) > Cognitive Psychology (Leeds)
Depositing User: Repository Officer
Date Deposited: 25 Jun 2009 13:32
Last Modified: 18 Jun 2015 17:29
Published Version: http://dx.doi.org/10.1007/s002219900258
Status: Published
Publisher: Springer Verlag
Identification Number: 10.1007/s002219900258
URI: http://eprints.whiterose.ac.uk/id/eprint/8691

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