T. D. Lee | PubMed Health

PubMed1995

Relative Phase Alterations During Bimanual Skill Acquisition.

The purposes of the research reported here were (a) to examine changes in relative phase during the acquisition of a new coordination pattern and (b) to determine the effect of learning this pattern on the ability to perform other coordination patterns. Ten subjects practiced an upper limb coordination task that required a 90 degrees phase offset and different amplitudes for each arm. A gross approximation of the mean relative phase for the intended coordination pattern occurred quickly, but the attainment of stability occurred much more gradually. These results were accompanied by changes in pattern stability across practice and on various transfer tests. Learning of the new coordination pattern also affected the stability of the antiphase mode, but this effect was only temporary.

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PubMed1994

Reducing Knowledge of Results About Relative Versus Absolute Timing: Differential Effects on Learning.

The purpose of the present experiment was to examine further earlier suggestions that a reduced relative frequency of knowledge of results (KR) can enhance the learning of generalized motor programs (GMPs) but at the same time degrade parameter learning, compared with giving KR after every trial (Wulf & Schmidt, 1989; Wulf, Schmidt, & Deubel, 1993). In contrast to these earlier studies, here KR was given separately for relative timing and absolute timing. Subjects practiced three movement patterns that required the same relative timing but different absolute movement times. KR was provided on 100% or 50% of the practice trials for relative timing or absolute timing, respectively. In retention and transfer tests, the groups that had had 50% KR about relative timing demonstrated more effective learning of the relative-timing structure, that is, GMP learning, than the groups that had had 100% KR about relative timing. The KR frequency had no effect on parameterization during retention; yet, when transfer to a task with a novel overall duration was required, the groups given 100% KR about absolute timing were more accurate in parameterization than the groups provided with 50% KR about absolute timing. Thus, the reduced relative KR frequency enhanced GMP learning but had no beneficial effect, or even a degrading effect, on parameter learning. The differential effects of a reduced KR frequency on the learning of relative timing and absolute timing also provide additional support for the dissociation of GMP and parameterization processes.

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