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Biomedical subjects

R A Magill

Publications and source records attributed to R A Magill.

15 recordsLinked to original sources
PubMed1998

Temporal and spatial adaptations during the acquisition of a reversal movement.

Adjustments of the biphasic movement in a coincidence anticipation task were studied using an erroneous knowledge of results (KR) paradigm. Forty participants received either no KR, correct KR, erroneous (+100 ms) KR, or 100 trials of correct KR followed by 50 trials of erroneous KR. Kinematic analyses revealed that for this 100-50 KR group the extension part of the movement was temporally adjusted under the influence of erroneous KR. Although accompanied by a decrease in movement amplitude, this did not account for the temporal shift in movement outcome, because all groups showed a reduction in amplitude. It is argued that changing external time constraints mainly results in temporal adaptations. However, spatial adaptations do play a role in kinematic changes during acquisition.

Adaptation, Physiological↗
PubMed1998

1997 C. H. McCloy Research Lecture: Knowledge is more than we can talk about: implicit learning in motor skill acquisition.

This article discusses the acquisition of knowledge about environmental regulatory features that guide the selection and execution of movements involved in performing open motor skills. First, empirical evidence related to the visual search characteristics of skilled and novice performers is considered to demonstrate that learning environmental regulatory features is an important part of performing an open motor skill. Then, the hypothesis is proposed and discussed that environmental regulatory features can, and probably should, be learned implicitly, which means the features can be learned and used, even though the learner is not consciously aware of the specific characteristics of those features. This article also discusses laboratory-based experiments that provide evidence supporting this hypothesis and presents implications for developing instructional strategies and practice conditions.

Humans↗
PubMed1998

Benefits of providing cognitive performance strategies to novice performers learning a complex motor skill.

Verbal reports were collected from experienced performers during acquisition trials of a novel throwing task and summarized as cognitive performance strategies. These strategies were incorporated in the practice regimen of 8 novices with no sport experience who learned the same task. A control group of 8 novices practiced the task without the experts' cognitive performance strategies. The performance of the novices who used the strategies was similar to that of the experts and significantly better than the performance of the control novices.

Achievement↗
PubMed1996

The contextual interference effect in parameter modifications of the same generalized motor program.

This study extended previous work (Sekiya, Magill, Sidaway, & Anderson, 1994) by examining whether the contextual interference (CI) effect could be found when task variations were controlled by the same generalized motor program (GMP) but differentiated on the basis of overall force parameter modifications. A subsidiary aim of this study was to determine how the amount of practice influenced the CI effect. During 2 acquisition sessions and 2 retention sessions, participants (N = 24) performed 3 task variations in either a blocked (low CI) or serial (high CI) condition. The task variations shared the same relative force structures but differed in the amount of overall force that had to be produced. Analysis of a general error measure revealed a strong CI effect, indicating that overall force parameter modifications of the same GMP created the CI effect. Analyses of various dependent measures, which dissociated GMP from parameter components with regard to force characteristics, revealed that parameter learning, but not GMP learning, was enhanced by high CI practice. No CI effect occurred in any aspect of timing characteristics. The amount of practice used in the present study did not influence the efficacy of the CI effect.

Adult↗
PubMed1994

The effects of erroneous knowledge of results on transfer of anticipation timing.

Previous research has shown that erroneous knowledge of results (KR) biased subjects' performance during retention trials for an anticipation timing task (Buekers, Magill, & Hall, 1992). The present experiment extended that work by investigating effects on novel transfer. During acquisition, three groups received either correct KR, erroneous KR, or 50 trials of correct KR followed by 25 trials of erroneous KR, where KR was the anticipation timing error in milliseconds. Erroneous KR was the actual timing error + 100 ms. One day later, subjects performed 15 trials without KR at each of two novel trackway speeds. Results showed that the bias acquired by the All-Erroneous KR condition during acquisition generalized across novel trackway speeds while the Mixed-Correct and Erroneous KR condition yielded a nonsignificant trend toward a response bias.

Adult↗
PubMed1994

The contextual interference effect for skill variations from the same and different generalized motor programs.

Magill and Hall (1990) hypothesized that the contextual interference (CI) effect is found only when task variations to be learned are governed by different generalized motor programs (GMPs). The present experiments examined their hypothesis by requiring subjects to learn variations of a tapping task that had either different (Experiment 1) or the same (Experiment 2) relative timing structure. In each experiment, subjects (N = 36) performed 270 acquisition trials with knowledge of results (KR) in either a blocked or a serial order. One day later, subjects performed 30 retention trials without KR. In data analyses, errors due to parameter modifications were dissociated from errors due to GMP construction to examine which process was responsible for the CI effect. In both experiments, parameter learning created a CI effect while GMP learning failed to produce a CI effect. In the light of these findings, a modification is proposed to the Magill and Hall (1990) hypothesis that takes into account these distinct processes in motor learning.

Adult↗
PubMed1989

Preparation and control of rapid, multisegmented responses in simple and choice environments.

Research investigating the preparation and control of rapid, multisegmented responses typically has assumed complete programming of the response occurring prior to movement initiation and has made use of a simple reaction time (RT) paradigm. A notable exception is Rosenbaum's work which proposed the Hierarchical Editor (HED) model that is specifically directed toward the control of movements in the choice environment. The purposes of this study were to investigate the assumption of complete programming prior to movement initiation and to compare predictions of the HED model with other programming models. Three experiments are reported in which subjects were required to tap either one, two, or three plates as rapidly as possible in either a simple or choice RT situation. The results were very consistent in these experiments even with several modifications in apparatus and methodology. Of particular interest were effects of movement complexity on RT and movement time (MT) for the first and second segments of the movement (M1 and M2). Choice RT (CRT) results consistently showed no increases in RT as the number of movement segments increased but showed significant increases in M1. For simple RT situations, however, there were small but consistent increases in RT as well as increases in M1 with increases in the number of movement parts. For both CRT and SRT results, small but nonsignificant increases were noted for M2. These results provide evidence for incomplete programming prior to response initiation. Although the SRT data can be accommodated by Henry's theory, the HED model appears to offer the best overall fit for the results.

Choice Behavior↗
PubMed1983

Distinctions in variability of motor output between learning disabled and normal children.

This study measured the differences in motor output between groups of 8- and 10-yr.-old learning disabled and normal boys. Variability of motor output was investigated by having children learn an alternating tapping task to a criterion of a specified number of taps per minute and then having them transfer to more difficult tapping tasks with the same rhythmic beat but requiring more distance to move or more accuracy. Results suggest variability of motor output distinguishes normal and learning disabled boys.

Attention↗
PubMed1979

Correlations among perceptual-motor ability, self-concept and reading achievement in early elementary grades.

This study investigated the correlation among measures of perceptual-motor abilities, self-concept, and reading achievement and determined whether perceptual-motor ability and self-concept can predict reading achievement in the early elementary grades. A total of 105 boys and 108 girls from the first, and second and third grades were tested on the stabilometer, a modified Minnesota Manual Dexterity Test, a tapping test, the Primary Self-concept Inventory, and the Science Research Associates Assessment Survey. Intercorrelations across grade levels tended to be low and nonsignificant. The multiple regression procedures yielded no strong predictions of reading achievement. These findings tended to confirm the specificity of perceptual-motor ability, self-concept, and reading achievement.

Achievement↗
PubMed1978

Variability of prior practice in learning and retention of a novel motor response.

The schema theory prediction that variability of practice would influence the strength of the motor response schema was investigated. Three groups of subjects, defined by much, little, or no variability of distances moved in prior practice on a linear-slide apparatus, completed 12 initial practice trials. Subjects then had 10 trials to estimate a novel distance from a new starting point. Knowledge of results was provided on the first three trials and withdrawn on the last seven trials. No differences in accuracy of production of the novel distance were noted although evidence for a stronger-schema by the group with little variability was noted on the second transfer trial. On the trials on which knowledge of results was withdrawn this stronger schema group maintained performance while the other two groups showed a decrement in performance.

Female↗
PubMed1975

Is the reaction time-movement time relationship 'essentially zero'?

It was hypothesized that, if RM-MT correlations are "essentially zero," then the magnitude of that correlation should not be subject to variation due to the manipulation of various experimental variables. In this experiment, Ss were tested with either RT-MT together or done separately. Results indicated significant relationships for 18 males but not for 18 females. The "essentially zero" position was discussed as being procedurally specific.

Adult↗