Authors: Zsolt Palatinus James A Dixon Damian G KeltyStephen
Publish Date: 2012/11/27
Volume: 41, Issue: 8, Pages: 1625-1634
Abstract
Movement science has traditionally understood highdimensional fluctuations as either antithetical or irrelevant to lowdimensional control However fluctuations incident to changeful sometimes unpredictable stimulation must somehow reshape lowdimensional aspects of control through perception The movement system’s fluctuations may reflect cascade dynamics in which manysized events interact nonlinearly across many scales Cascades yield fractal fluctuations and fractality of fluctuations may provide a window on the interactions across scale supporting perceptual processes To test these ideas we asked adult human participants to judge whole or partial length for unseen rods with and without added masses The participants’ only experience with the objects came from supporting them across their shoulders during quiet standing First the degree of fractal temporal correlations in trialbytrial series of planar Euclidean displacements in center of pressure COP significantly improved prediction of subsequent trialbytrial judgments above and beyond prediction by traditional predictors of haptic perception and conventional measures of COP variability Second comparison with linear surrogate data indicated the presence of nonlinear interactions across scale in these time series These results demonstrate that highdimensional fluctuations may serve a crucial role in the cascade dynamics supporting apparently lowdimensional control strategies
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