To study the acquisition of perceptual-motor skills as an instance of dynamic pattern formation, we examined the evolution of postural sway and eye and head movements in relation to changes in performance, while 13 novices practiced 3-ball cascade juggling for 9 weeks. Ball trajectories, postural sway, and eye and head movements were recorded repeatedly. Performance improved exponentially, both in terms of the number of consecutive throws and the degree of frequency and phase locking between the ball trajectories. These aspects of performance evolved at different time scales, indicating the presence of a temporal hierarchy in learning. Postural sway, and eye and head movements were often 3:2 and sometimes 3:1 frequency locked to the ball trajectories. As a rule, the amplitudes of these oscillatory processes decreased exponentially at rates similar to that of the increase in the degree of phase locking between the balls. In contrast, the coordination between these oscillatory processes evolved exponentially at different time scales, apart from some erratic evolutions. Collectively, these findings indicate that skill acquisition in the perceptual-motor domain involves multiple time scales and multiform dynamics, both in terms of the development of the goal behavior itself and the evolution of the processes subserving this goal behavior.
Raoul Huys, Andreas Daffertshofer and Peter J. Beek
Yeou-Teh Liu, Tsung-Yu Hsieh and Karl M. Newell
Recent studies have shown more than one time scale of change in the movement dynamics of practice. Here, we decompose the drift and diffusion dynamics in adaptation to performing discrete aiming movements with different space-time constraints. Participants performed aiming movements on a graphics drawing board to a point target at 5 different space-time weightings on the task outcome. The drift was stronger the shorter the time constraint whereas noise was U-shaped across the space-time conditions. The drift and diffusion of adaptation in discrete aiming movements varied as a function of the space-time constraints on performance outcome and the spatial, temporal, or space-time measure of performance outcome. The findings support the postulation that the time scale of movement adaptation is task dependent.
Satyajit Ambike, Daniela Mattos, Vladimir Zatsiorsky and Mark Latash
Cyclic isometric finger-force patterns established using visual feedback show systematic drifts when the feedback is removed. Force changes at multiple time scales and in opposite directions have been reported. For further characterization of these drifts, healthy subjects produced isometric, cyclic finger force with and without visual feedback at various initial amplitudes and frequencies. We hypothesized that on feedback removal, the amplitude will be attracted toward a preferred value that is frequency dependent. We found that the amplitude always increased after feedback removal. The magnitude of the amplitude increase changed with initial frequency, but it was invariant over the explored range of initial amplitudes. Thus, the existence of a preferred amplitude of force oscillations was not supported. We interpret these results within the referent configuration and the referent configuration back-coupling hypotheses. These data will inform a mathematical model of finger-force drifts. However, currently, they raise more questions than they answer, and a coherent account of finger-force drifts remains a challenge.
Ruud J. R. Den Hartigh, Ralf F. A. Cox, Christophe Gernigon, Nico W. Van Yperen and Paul L. C. Van Geert
The aim of this study was to examine (1) the temporal structures of variation in rowers’ (natural) ergometer strokes to make inferences about the underlying motor organization, and (2) the relation between these temporal structures and skill level. Four high-skilled and five lower-skilled rowers completed 550 strokes on a rowing ergometer. Detrended Fluctuation Analysis was used to quantify the temporal structure of the intervals between force peaks. Results showed that the temporal structure differed from random, and revealed prominent patterns of pink noise for each rower. Furthermore, the high-skilled rowers demonstrated more pink noise than the lower-skilled rowers. The presence of pink noise suggests that rowing performance emerges from the coordination among interacting component processes across multiple time scales. The difference in noise pattern between high-skilled and lower-skilled athletes indicates that the complexity of athletes’ motor organization is a potential key characteristic of elite performance.
* Benoît G. Bardy * Thomas A. Stoffregen * Reinoud J. Bootsma * 4 2004 8 2 174 187 10.1123/mcj.8.2.174 Multiple Time Scales and Multiform Dynamics in Learning to Juggle Raoul Huys * Andreas Daffertshofer * Peter J. Beek * 4 2004 8 2 188 212 10.1123/mcj.8.2.188 Contextual Interference: Single
Adam C. King
account the multiple time scales of the CoP trajectories to provide a complexity index (CI) of each CoP trajectory through a coarse grain analysis of each time series. 15 , 16 The implementation of MultiEn uses a same entropy calculation and computes the regularity of successive, smoothed time series (eg
Yumeng Li, Melissa A. Mache and Teri A. Todd
physiological complexity. 18 Multiscale entropy is a nonlinear analysis tool to quantify complexity or irregularity of a time-series signal over multiple time scales. Compared with approximate entropy and sample entropy, multiscale entropy quantifies the overall complexity of a system and allows researchers to
Ing-Shiou Hwang, Chia-Ling Hu, Wei-Min Huang, Yi-Ying Tsai and Yi-Ching Chen
production . Journal of Neurophysiology, 84 ( 4 ), 1708 – 1718 . PubMed ID: 11024063 doi: 10.1152/jn.2000.84.4.1708 Sosnoff , J.J. , & Newell , K.M. ( 2005 ). Intermittent visual information and the multiple time scales of visual motor control of continuous isometric force production . Perception
Karl M. Newell
skills confirming that our time scale divisions of phylogenetic/ontogenetic and chronological age for analysis are primarily conveniences of description. Figure 2 —Multiple time scales of development. This figure depicts an elaborated form of Waddington’s landscape. Adapted by Thelen and Smith ( 1994
Bimanual Action John J. Buchanan, Texas A&M University; Inchon Park, Korea Institute of Sports Science; Austin T. McCulloch, Texas A&M University Motor skills are encoded in both motor and spatial representations. Consolidation as a process operates on multiple time-scales. Short time scales are defined as