Line bisection by eye and by hand reveal opposite biases

Details

Serval ID
serval:BIB_5EF7A3A0F70A
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Line bisection by eye and by hand reveal opposite biases
Journal
Experimental Brain Research
Author(s)
Leonards U., Stone S., Mohr C.
ISSN
0014-4819
Publication state
Published
Issued date
2013
Peer-reviewed
Oui
Volume
228
Number
4
Pages
513-525
Language
english
Abstract
The vision-for-action literature favours the idea that the motor output of an action - whether manual or oculomotor - leads to similar results regarding object handling. Findings on line bisection performance challenge this idea: healthy individuals bisect lines manually to the left of centre, and to the right of centre when using eye fixation. In case that these opposite biases for manual and oculomotor action reflect more universal compensatory mechanisms that cancel each other out to enhance overall accuracy, one would like to observe comparable opposite biases for other material. In the present study, we report on three independent experiments in which we tested line bisection (by hand, by eye fixation) not only for solid lines, but also for letter lines; the latter, when bisected manually, is known to result in a rightward bias. Accordingly, we expected a leftward bias for letter lines when bisected via eye fixation. Analysis of bisection biases provided evidence for this idea: manual bisection was more rightward for letter as compared to solid lines, while bisection by eye fixation was more leftward for letter as compared to solid lines. Support for the eye fixation observation was particularly obvious in two of the three studies, for which comparability between eye and hand action was increasingly adjusted (paper-pencil versus touch screen for manual action). These findings question the assumption that ocular motor and manual output are always inter-changeable, but rather suggest that at least for some situations ocular motor and manual output biases are orthogonal to each other, possibly balancing each other out.
Keywords
hemi-spatial attention, letter line bisection, language, pseudoneglect
Pubmed
Create date
16/05/2013 20:09
Last modification date
20/08/2019 15:16
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