Citation

Rhea CK, Rietdyk S, Haddad JM. PLoS One 2010; 5(7): e11544.

Affiliation

Department of Health and Kinesiology, Purdue University, West Lafayette, Indiana, United States of America. christopher_rhea@brown.edu

Copyright

(Copyright © 2010, Public Library of Science)

DOI

10.1371/journal.pone.0011544

PMID

20634962

PMCID

PMC2902523

Abstract

BACKGROUND: During locomotion, vision is used to perceive environmental obstacles that could potentially threaten stability; locomotor action is then modified to avoid these obstacles. Various factors such as lighting and texture can make these environmental obstacles appear larger or smaller than their actual size. It is unclear if gait is adapted based on the actual or perceived height of these environmental obstacles. The purposes of this study were to determine if visually guided action is scaled to visual perception, and to determine if task experience influenced how action is scaled to perception. METHODOLOGY/PRINCIPAL FINDINGS: Participants judged the height of two obstacles before and after stepping over each of them 50 times. An illusion made obstacle one appear larger than obstacle two, even though they were identical in size. The influence of task experience was examined by comparing the perception-action relationship during the first five obstacle crossings (1-5) with the last five obstacle crossings (46-50). In the first set of trials, obstacle one was perceived to be 2.0 cm larger than obstacle two and subjects stepped 2.7 cm higher over obstacle one. After walking over the obstacle 50 times, the toe elevation was not different between obstacles, but obstacle one was still perceived as 2.4 cm larger. CONCLUSIONS/SIGNIFICANCE: There was evidence of locomotor adaptation, but no evidence of perceptual adaptation with experience. These findings add to research that demonstrates that while the motor system can be influenced by perception, it can also operate independent of perception.

Language: en