Document Detail


The effect of illusory size on force production when grasping objects.
MedLine Citation:
PMID:  11156317     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Milner and Goodale (1995) have proposed that visuomotor and perceptual processes are mediated by discrete visual systems that reflect the functional independence of action and perception. The visuomotor system is proposed to be insensitive to pictorial illusions of object size, whereas the perceptual system is reliably "tricked" by such figures. Brenner and Smeets (1996) and Jackson and Shaw (2000) demonstrated that grasp preshaping, but not grasping force, is immune to the Ponzo visual illusion, suggesting that not all visuomotor processes operate independently of the perceptual system. The present study investigated the effect of illusory object size on prehension kinematics and grasping dynamics (i.e., grip force and load force) as well as perceptual judgements of object size. Unlike previous investigations, object mass was held constant independent of changes in size. The Ponzo figure reliably affected perceptual estimates of object size, but this effect was restricted to one form of the illusion. Some aspects of the prehension movement were sensitive to veridical but not illusory object size (peak grip aperture, peak grip force, peak vertical wrist acceleration), whereas other movement parameters demonstrated illusory size effects (movement time, peak wrist velocity). Still other movement parameters were not sensitive to veridical or illusory object size (peak load force). Together the data suggest that certain prehension components are immune to pictorial illusions of object size, whereas others are not. Complex interactions between the perceptual and visuomotor systems appear to underlie the anticipatory scaling of grasping forces in prehension.
Authors:
D A Westwood; A Dubrowski; H Carnahan; E A Roy
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale     Volume:  135     ISSN:  0014-4819     ISO Abbreviation:  Exp Brain Res     Publication Date:  2000 Dec 
Date Detail:
Created Date:  2001-01-11     Completed Date:  2001-03-08     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0043312     Medline TA:  Exp Brain Res     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  535-43     Citation Subset:  IM    
Affiliation:
Department of Psychology, University of Waterloo, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Acceleration
Adult
Biomechanics
Female
Form Perception / physiology*
Hand Strength / physiology*
Humans
Illusions / physiology*
Male
Photic Stimulation
Psychomotor Performance / physiology*
Weight-Bearing

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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