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Learning vs. minding: How subjective costs can mask motor learning

When learning new movements some people make larger kinematic errors than others, interpreted as a reduction in motor-learning ability. Consider a learning task where error-cancelling strategies incur higher effort costs, specifically where subjects reach to targets in a force field. Concluding that...

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Autores principales: Healy, Chadwick M., Berniker, Max, Ahmed, Alaa A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10019678/
https://www.ncbi.nlm.nih.gov/pubmed/36928111
http://dx.doi.org/10.1371/journal.pone.0282693
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author Healy, Chadwick M.
Berniker, Max
Ahmed, Alaa A.
author_facet Healy, Chadwick M.
Berniker, Max
Ahmed, Alaa A.
author_sort Healy, Chadwick M.
collection PubMed
description When learning new movements some people make larger kinematic errors than others, interpreted as a reduction in motor-learning ability. Consider a learning task where error-cancelling strategies incur higher effort costs, specifically where subjects reach to targets in a force field. Concluding that those with greater error have learned less has a critical assumption: everyone uses the same error-canceling strategy. Alternatively, it could be that those with greater error may be choosing to sacrifice error reduction in favor of a lower effort movement. Here, we test this hypothesis in a dataset that includes both younger and older adults, where older adults exhibited greater kinematic errors. Utilizing the framework of optimal control theory, we infer subjective costs (i.e., strategies) and internal model accuracy (i.e., proportion of the novel dynamics learned) by fitting a model to each population’s trajectory data. Our results demonstrate trajectories are defined by a combination of the amount learned and strategic differences represented by relative cost weights. Based on the model fits, younger adults could have learned between 65–90% of the novel dynamics. Critically, older adults could have learned between 60–85%. Each model fit produces trajectories that match the experimentally observed data, where a lower proportion learned in the model is compensated for by increasing costs on kinematic errors relative to effort. This suggests older and younger adults could be learning to the same extent, but older adults have a higher relative cost on effort compared to younger adults. These results call into question the proposition that older adults learn less than younger adults and provide a potential explanation for the equivocal findings in the literature. Importantly, our findings suggest that the metrics commonly used to probe motor learning paint an incomplete picture, and that to accurately quantify the learning process the subjective costs of movements should be considered.
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spelling pubmed-100196782023-03-17 Learning vs. minding: How subjective costs can mask motor learning Healy, Chadwick M. Berniker, Max Ahmed, Alaa A. PLoS One Research Article When learning new movements some people make larger kinematic errors than others, interpreted as a reduction in motor-learning ability. Consider a learning task where error-cancelling strategies incur higher effort costs, specifically where subjects reach to targets in a force field. Concluding that those with greater error have learned less has a critical assumption: everyone uses the same error-canceling strategy. Alternatively, it could be that those with greater error may be choosing to sacrifice error reduction in favor of a lower effort movement. Here, we test this hypothesis in a dataset that includes both younger and older adults, where older adults exhibited greater kinematic errors. Utilizing the framework of optimal control theory, we infer subjective costs (i.e., strategies) and internal model accuracy (i.e., proportion of the novel dynamics learned) by fitting a model to each population’s trajectory data. Our results demonstrate trajectories are defined by a combination of the amount learned and strategic differences represented by relative cost weights. Based on the model fits, younger adults could have learned between 65–90% of the novel dynamics. Critically, older adults could have learned between 60–85%. Each model fit produces trajectories that match the experimentally observed data, where a lower proportion learned in the model is compensated for by increasing costs on kinematic errors relative to effort. This suggests older and younger adults could be learning to the same extent, but older adults have a higher relative cost on effort compared to younger adults. These results call into question the proposition that older adults learn less than younger adults and provide a potential explanation for the equivocal findings in the literature. Importantly, our findings suggest that the metrics commonly used to probe motor learning paint an incomplete picture, and that to accurately quantify the learning process the subjective costs of movements should be considered. Public Library of Science 2023-03-16 /pmc/articles/PMC10019678/ /pubmed/36928111 http://dx.doi.org/10.1371/journal.pone.0282693 Text en © 2023 Healy et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Healy, Chadwick M.
Berniker, Max
Ahmed, Alaa A.
Learning vs. minding: How subjective costs can mask motor learning
title Learning vs. minding: How subjective costs can mask motor learning
title_full Learning vs. minding: How subjective costs can mask motor learning
title_fullStr Learning vs. minding: How subjective costs can mask motor learning
title_full_unstemmed Learning vs. minding: How subjective costs can mask motor learning
title_short Learning vs. minding: How subjective costs can mask motor learning
title_sort learning vs. minding: how subjective costs can mask motor learning
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10019678/
https://www.ncbi.nlm.nih.gov/pubmed/36928111
http://dx.doi.org/10.1371/journal.pone.0282693
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