The Complexity of Postural Sway Effects on Affordance Perception in Young and Older Adults
Abstract
Affordances are the action possibilities based on the environment and an individual’s capabilities, but the perception of these affordances may not align with reality, potentially leading to an unstable position and increasing falling risk. Although postural complexity has been shown to improve affordance perception in young adults within virtual reality, its trajectory across age groups and its role in real-world perceptual-motor calibration remain unclear. This study examined how postural complexity is associated with the perception of reachability in young and older adults. Twenty young adults and twenty older adults judged whether objects placed at varying distances on a table were within reach while standing in three foot positions (feet shoulder-width apart, feet together, and feet in semi-tandem). Postural complexity (sample entropy) and linear measures of the center of pressure (area, standard deviation, mean velocity) were recorded, along with perceptual accuracy (perceptual judgements in comparison to actual reachability). Overall, young adults had slightly higher perceptual accuracy in each foot position, but no significant age group differences emerged, despite higher sway in older adults. Foot position systematically altered complexity, revealing directional mechanistic changes. Contrary to expectations, older adults exhibited higher center of pressure complexity than young adults, and lower center of pressure complexity was associated with more accurate perception, particularly in the ML direction. These findings suggest that greater complexity may be associated with less precise real-world perceptual-motor calibration, and that postural complexity does not uniformly decline with age. Further, complexity may be dependent on the measurement technique, task constraints, and the specific demands placed on the postural control system.
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BibTeX
@misc{ong2026complexity,
title = {{The Complexity of Postural Sway Effects on Affordance Perception in Young and Older Adults}},
author = {Haley Ong and Lucas Michaud and Yves Lajoie},
howpublished = {PsyArXiv},
year = {2026},
month = oct,
doi = {10.31234/osf.io/29w3j_v1},
url = {https://osf.io/preprints/psyarxiv/29w3j_v1/},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The Complexity of Postural Sway Effects on Affordance Perception in Young and Older Adults
AU - Haley Ong
AU - Lucas Michaud
AU - Yves Lajoie
PY - 2026
DA - 2026/10/20
PB - PsyArXiv
DO - 10.31234/osf.io/29w3j_v1
UR - https://osf.io/preprints/psyarxiv/29w3j_v1/
AB - Affordances are the action possibilities based on the environment and an individual’s capabilities, but the perception of these affordances may not align with reality, potentially leading to an unstable position and increasing falling risk. Although postural complexity has been shown to improve affordance perception in young adults within virtual reality, its trajectory across age groups and its role in real-world perceptual-motor calibration remain unclear. This study examined how postural complexity is associated with the perception of reachability in young and older adults. Twenty young adults and twenty older adults judged whether objects placed at varying distances on a table were within reach while standing in three foot positions (feet shoulder-width apart, feet together, and feet in semi-tandem). Postural complexity (sample entropy) and linear measures of the center of pressure (area, standard deviation, mean velocity) were recorded, along with perceptual accuracy (perceptual judgements in comparison to actual reachability). Overall, young adults had slightly higher perceptual accuracy in each foot position, but no significant age group differences emerged, despite higher sway in older adults. Foot position systematically altered complexity, revealing directional mechanistic changes. Contrary to expectations, older adults exhibited higher center of pressure complexity than young adults, and lower center of pressure complexity was associated with more accurate perception, particularly in the ML direction. These findings suggest that greater complexity may be associated with less precise real-world perceptual-motor calibration, and that postural complexity does not uniformly decline with age. Further, complexity may be dependent on the measurement technique, task constraints, and the specific demands placed on the postural control system.
ER -