Egocentric haptic matching is not dominated by visual information
Poster Presentation

Amanda Kaas
Dept. Cognitive Neuroscience, Faculty of Psychology, University Maastricht

Johan Lataster

Mirella Fingal

Alex Sack

     Abstract ID Number: 99
     Full text: Not available
     Last modified: March 21, 2005

Abstract
Systematic errors were found when blindfolded participants performed allocentric haptic tasks, in which they matched the orientations of two bars by making them parallel [1, 2]. In contrast, smaller errors were observed when the haptic matching instruction allowed both an egocentric and an allocentric strategy, e.g., when participants rotated a test bar to create the mirror image of a reference bar with respect to the body symmetry-plane [3,4]. It has been argued that mirror and parallel matching are performed in the same intermediate reference frame [3]. However, non-informative vision improved only haptic parallel matching, possibly facilitating the switch to more allocentric representations [5, 6].
The present study investigated the effect of adding congruent and incongruent visual information in allocentic and egocentric haptic orientation matching tasks. Thirty healthy right-handed participants performed bimanual haptic mirror symmetry matching and parallel matching. During haptic exploration participants received congruent, incongruent or no visual information.
Results showed that visual congruent information significantly improved allocentric performance. However, visual information did not affect egocentric task performance. This suggests that visual representations are less important for egocentric haptic tasks, and indicates that the dominance of visual information depends on the appropriateness for the task at hand.

[1] Kappers et al., 1999
[2] Kappers et al., 2003
[3] Kappers, 2004
[4] Kaas et al, submitted
[5] Zuidhoek et al., 2004
[6] Newport et al., 2002