Search

There is evidence that actions are planned by anticipation of their external effects, with the strength of this effect being dependent on the amount of prior practice. In Experiment 1, skilled soccer players performed a kicking task under four conditions: planning in terms of an external action effect (i.e., ball trajectory) or in terms of body movements, either with or without visual error feedback. When feedback was withheld, a ball focus resulted in more accurate outcomes than a body focus. When visual feedback was allowed, there was no difference between these two conditions. In Experiment 2, both skilled and novice soccer players were tested with the addition of a control condition and in the absence of visual feedback. For both groups there was evidence that a ball focus was more beneficial for performance than a body focus, particularly in terms of movement kinematics where correlations across the joints were generally higher for body rather than ball planning. Most skilled participants reported that ball planning felt more normal than body planning. These experiments provide some evidence that actions are planned in terms of their external action effects, supporting the common-coding hypothesis of action planning. [ABSTRACT FROM AUTHOR]

The importance of action-effects for the performance of a soccer kick was examined. Novice, intermediate, and skilled players performed a soccer chip task with the intention of getting the ball over a height barrier to a near or far ground-level target under three conditions: full vision, no vision following ball contact with and without knowledge of results (KR). The removal of vision of the ball trajectory resulted in increased radial error, irrespective of the presence or absence of KR but in a skill-level and target dependent manner. At the near target, novice participants relied on ball trajectory information. Intermediate performers were affected by its removal across both target conditions, whereas skilled participants were not affected by the removal of ball vision. Variability in knee-ankle coordination significantly decreased when vision of the ball trajectory was removed, irrespective of KR and skill level. Although across skill level there was evidence that action-effects information is used to execute the action when it is available, only at the lower levels of skill did this information aid outcome attainment. There was no evidence to suggest that with increasing skill the dependence on this information increases. [ABSTRACT FROM AUTHOR]

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 perceptualmotor 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. [ABSTRACT FROM AUTHOR]