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The size of the visual size cue used for programming manipulative forces during precision grip

Mon-Williams, M. and Murray, A.H. (2000) The size of the visual size cue used for programming manipulative forces during precision grip. Experimental Brain Research, 135 (3). pp. 405-410. ISSN 0014-4819

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We used a perturbation technique to quantify the contribution of visual size cues to the programming of target force when lifting an object. Our results indicate that the nervous system attaches a reasonable weight to visual size cues when programming the target grip force for a novel object. In a subsequent lift of the same object, however, the confidence attached to the visual size cue fell dramatically. It is not clear whether the decrease in the use of size information was accelerated by the presence of a cue conflict or whether the fall represents the normal shift towards the use of a memorybased representation for programming grip force. In a second experiment, we used the “size-weight illusion” to explore the relationship between the verbal report of an object’s weight and the programming of the grip and load force. We found that erroneous motor programming (as indexed by a number of measures) was neither necessary nor sufficient for the size-weight illusion to occur. These findings call for a re-evaluation of a previous explanation for the size-weight illusion. We suggest that the illusion arises because the cognitive system attempts to rationalise the fact that objects of apparently equal density but different size feel as if they have the same weight.

Item Type: Article
Keywords: prehension; precision grip; motor programming; visual cues; size-weight illusion; human
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 10:38
Last Modified: 18 Jun 2015 17:29
Published Version: http://dx.doi.org/10.1007/s002210000538
Status: Published
Publisher: Springer Verlag
Identification Number: 10.1007/s002210000538
URI: http://eprints.whiterose.ac.uk/id/eprint/8683

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