Motor cost influences perceptual decisions

Perceptual decision making has been widely studied using tasks in which subjects are asked to discriminate a visual stimulus and instructed to report their decision with a movement. In these studies, performance is measured by assessing the accuracy of the participants’ choices as a function of the...

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Detalhes bibliográficos
Autores: Marcos Sanmartín, Encarni, Cos Aguilera, Ignasi, Girard, Benoît, Verschure, Paul F. M. J.
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2015
País:España
Recursos:Universitat Pompeu Fabra
Repositorio:Repositorio Digital de la UPF
OAI Identifier:oai:repositori.upf.edu:10230/26295
Acesso em linha:http://hdl.handle.net/10230/26295
http://dx.doi.org/10.1371/journal.pone.0144841
Access Level:acceso abierto
Palavra-chave:Decision making
Vision
Musculoskeletal system
Sensory perception
Ellipses
Cognition
Elbow
Shoulders
Descrição
Resumo:Perceptual decision making has been widely studied using tasks in which subjects are asked to discriminate a visual stimulus and instructed to report their decision with a movement. In these studies, performance is measured by assessing the accuracy of the participants’ choices as a function of the ambiguity of the visual stimulus. Typically, the reporting movement is considered as a mere means of reporting the decision with no influence on the decision-making process. However, recent studies have shown that even subtle differences of biomechanical costs between movements may influence how we select between them. Here we investigated whether this purely motor cost could also influence decisions in a perceptual discrimination task in detriment of accuracy. In other words, are perceptual decisions only dependent on the visual stimulus and entirely orthogonal to motor costs? Here we show the results of a psychophysical experiment in which human subjects were presented with a random dot motion discrimination task and asked to report the perceived motion direction using movements of different biomechanical cost. We found that the pattern of decisions exhibited a significant bias towards the movement of lower cost, even when this bias reduced performance accuracy. This strongly suggests that motor costs influence decision making in visual discrimination tasks for which its contribution is neither instructed nor beneficial.