Conceptions of Ability Affect Motor Learning

ABSTRACT

The authors examined the effects of induced conceptions of ability on motor learning. Participants in 3 groups practiced a balance task after receiving instructions suggesting that the task would reflect an inherent ability (IA group), represent an acquirable skill (AS group), or no ability-related instructions (control group). Across 2 days of practice, the AS and IA groups showed greater improvement in performance compared with the control group. For the retention test on Day 3, the AS group tended to demonstrate generally more effective balance performance than the control group and increasingly greater effectiveness compared with the IA group. Moreover, AS group participants made higher-frequency (reflexive) movement adjustments than participants of the other 2 groups, indicating a greater automaticity in the control of their movements. Thus, learning was enhanced by instructions portraying the task as a learnable skill, rather than revealing a fixed inherent capacity or no instructions (control group).     

Social-comparative feedback affects motor skill learning

This study examined motivational effects of feedback on motor learning. Specifically, we investigated the influence of social-comparative feedback on the learning of a balance task (stabilometer). In addition to veridical feedback (error scores reflecting deviation from the target horizontal platform position) about their own performance after each trial, two groups received false normative information about the “average” score of others on that trial. Average performance scores indicated that the participant's performance was either above (better group) or below (worse group) the average, respectively. A control group received veridical feedback about trial performance without normative feedback. Learning as a function of social-comparative feedback was determined in a retention test without feedback, performed on a third day following two days of practice. Normative feedback affected the learning of the balance task: The better group demonstrated more effective balance performance than both the worse and control groups on the retention test. Furthermore, high-frequency/low-amplitude balance adjustments, indicative of more automatic control of movement, were greater in the better than in the worse group. The control group exhibited more limited learning and less automaticity than both the better and the worse groups. The findings indicate that positive normative feedback had a facilitatory effect on motor learning.     

Learning complex upper-limb movements through practicing movement elements

Upper-limb complex movements constitute a major part of our daily activities. Research shows complex movements are generated by sequences of movement elements represented by a unimodal bell-shaped velocity curve. We utilized this understanding in the field of motor skill acquisition and hypothesized that practicing a movement element of a complex movement trajectory will facilitate the performance on the respective complex movement trajectory. To test this, we designed an experiment where the control group learned a full complex trajectory, whereas the two elemental groups learned two different movement elements of the complex trajectory. The two main outcome measures explaining the performance were accuracy and speed. The elemental groups, after training on movement elements, significantly improved their speed and accuracy when tested on the full complex trajectory. The result illustrated that training on a movement element of a complex trajectory benefited the performance of the full complex trajectory. The two elemental groups showed similar improvements in the performance of the complex motor skill, despite obtaining training on different movement elements of the same complex movement. The findings show that complex movements can be learned by practicing their movement elements.     

EMG and motor performance changes with practice of a forearm movement by children

The purpose of this research was to investigate changes in the control of movement, using EMG and kinematic variables, over practice by children. Children in three age groups, 7, 9, and 11 yr., performed 60 trials of an elbow-flexion movement. Correct movements consisted of a 60 degrees angular movement of the forearm in 800 msec. The analysis of biceps brachii and triceps brachii muscle EMG activity, movement displacement and timing error, and movement velocity patterns indicated changes in motor performance with practice. All age groups improved performance with practice and also exhibited a decrease in biceps EMG activity with practice. Only movement-time error and time to peak triceps muscle activity differed between the age groups. The 11-yr.-old group significantly altered the timing of the antagonistic response to stop the movement over the practice session. This change is suggested to be related to the greater information-processing ability of these children and the development of appropriate movement strategies to perform the movement task successfully. Other changes observed in the EMG data appear similar to changes observed in studies of adults.     

Developmental features of rapid aiming arm movements across the lifespan

Using a lifespan approach, the authors investigated developmental features of the control of ballistic aiming arm movements by manipulating movement complexity, response uncertainty, and the use of precues. Four different age groups of participants (6- and 9-year-old boys and girls and 24- and 73-year-old men and women, 20 participants in each age group) performed 7 types of rapid aiming arm movements on the surface of a digitizer. Their movement characteristics such as movement velocity, normalized jerk, relative timing, movement linearity, and intersegment intervals were profiled. Analyses of variance with repeated measures were conducted on age and task effects in varying movement complexity (Study 1), response uncertainty (Study 2), and precue use (Study 3) conditions. Young children and senior adults had slower, more variant, less smooth, and less linear arm movements than older children and young adults. Increasing the number of movement segments resulted in slower and more variant responses. Movement accuracy demands or response uncertainty interacted with age so that the 6- and 74-year-old participants had poorer performances but responded similarly to the varying treatments. Even though older children and young adults had better performances than young children and senior adults, their arm movement performance declined when response uncertainty increased. The analyses suggested that young children's and senior adults' performances are poorer because less of their movement is under central control, and they therefore use on-line adjustments. In addition, older children and young adults use a valid precue more effectively to prepare for subsequent movements than do young children and senior adults, suggesting that older children and young adults are more capable of organizing motor responses than are young children and senior adults.     

Exploring how arm movement moderates the effect of task difficulty on balance performance in young and older adults

Emerging evidence highlights that arm movements exert a substantial and functionally relevant contribution on quiet standing balance control in young adults. Ageing is associated with “non-functional” compensatory postural control strategies (i.e., lower limb co-contraction), which in turn, may increase the reliance on an upper body strategy to control upright stance. Thus, the primary purpose of this study was to compare the effects of free versus restricted arm movements on balance performance in young and older adults, during tasks of different difficulty. Fifteen young (mean ± SD age; 21.3 ± 4.2 years) and fifteen older (mean ± SD age; 73.3 ± 5.0 years) adults performed bipedal, semi-tandem and tandem balance tasks under two arm position conditions: restricted arm movements and free arm movements. Centre of pressure (COP) amplitude and frequency were calculated as indices of postural performance and strategy, respectively. Especially in older adults, restriction of arm movement resulted in increased sway amplitude and frequency, which was primarily observed for the mediolateral direction. Further, increasing balance task difficulty raised the arm restriction cost (ARC; a new measure to quantify free vs. restricted arm movement differences in postural control) that was more prominent in older adults. These findings indicate the ARC provides a measure of reliance on the upper body for balance control and that arm movement is important for postural control in older adults, especially during tasks of greater difficulty.     

Developmental Features of Rapid Aiming Arm Movements Across the Lifespan

Using a lifespan approach, the authors investigated developmental features of the control of ballistic aiming arm movements by manipulating movement complexity, response uncertainty, and the use of precues. Four different age groups of participants (6- and 9-year-old boys and girls and 24- and 73-year- old men and women, 20 participants in each age group) performed 7 types of rapid aiming arm movements on the surface of a digitizer. Their movement characteristics such as movement velocity, normalized jerk, relative timing, movement linearity, and intersegment intervals were profiled. Analyses of variance with repeated measures were conducted on age and task effects in varying movement complexity (Study 1), response uncertainty (Study 2), and precue use (Study 3) conditions. Young children and senior adults had slower, more variant, less smooth, and less linear arm movements than older children and young adults. Increasing the number of movement segments resulted in slower and more variant responses. Movement accuracy demands or response uncertainty interacted with age so that the 6- and 74-year-old participants had poorer performances but responded similarly to the varying treatments. Even though older children and young adults had better performances than young children and senior adults, their arm movement performance declined when response uncertainty increased. The analyses suggested that young children's and senior adults' performances are poorer because less of their movement is under central control, and they therefore use on-line adjustments. In addition, older children and young adults use a valid precue more effectively to prepare for subsequent movements than do young children and senior adults, suggesting that older children and young adults are more capable of organizing motor responses than arc young children and senior adults.     

Training of efficient oculomotor strategies enhances skill acquisition

The present study investigated the hypothesis that efficient oculomotor behaviours can be acquired through practice on a series of simple tasks and can be transferred subsequently to a complex visuomotor task, such as a video game. Each of two groups of subjects were exposed to a different set of simple tasks, or drills. One group, the efficient eye movement experimental group, received training designed to minimize eye movements and optimize scan path behaviours, whereas a second group of subjects, the inefficient eye movement experimental group, received training designed to increase the frequency of eye movements. Oculomotor training was interspersed with practice on the video game. Performance of these two experimental groups in the video game was compared to a control group playing the video game but receiving no specific training and matched for total time in the experiment. The group receiving efficient oculomotor training exhibited significantly superior performance in the video game and fewer foveations than either the inefficient or control groups, which did not differ from each other. Overall there was a significant inverse correlation between the number of foveations in the game and game score. The results of this study are discussed in terms of their implications for the importance of oculomotor training in the acquisition of any complex perceptual motor task.     

Developmental trends in speed accuracy trade-off in 6-10-year-old children performing rapid reciprocal and discrete aiming movements

Cyclic tasks are performed better than discrete tasks in adults but it is unknown whether this advantage is present in children as well. Three age groups of participants (6, 8, and 10 years old) executed cyclic and discrete aiming movements to two differently sized target using a Fitts task to examine the developmental effects on speed/accuracy trade-off. Children showed the same advantage of cyclic over discrete movements as previously demonstrated for adults but at a slower speed. The slope of the speed accuracy trade-off was similar in the three age groups in the cyclic as compared to the discrete control mode, suggesting that children learn both tasks equally well in this age range. The index of performance (IP) increased with age but not differently for the two control modes. Children showed clear differences between the kinematics of discrete and cyclic movements and these differences were similar to those seen in adults. Cyclic movements were faster, had higher IP, showed fewer changes in velocity and were more ballistic. Thus movement execution was different between the two tasks, consistent with the hypothesis that cyclic tasks make use of neural oscillators. The slower movement speed in young children is consistent with their limited ability to use open loop control.     

Training compliance control yields improved drawing in 5–11 year old children with motor difficulties

There are a large number of children with motor difficulties including those that have difficulty producing movements qualitatively well enough to improve in perceptuo-motor learning without intervention. We have developed a training method that supports active movement generation to allow improvement in a 3D tracing task requiring good compliance control. Previously, we tested a limited age range of children and found that training improved performance on the 3D tracing task and that the training transferred to a 2D drawing test. In the present study, school children (5–11 years old) with motor difficulties were trained in the 3D tracing task and transfer to a 2D drawing task was tested. We used a cross-over design where half of the children received training on the 3D tracing task during the first training period and the other half of the children received training during the second training period. Given previous results, we predicted that younger children would initially show reduced performance relative to the older children, and that performance at all ages would improve with training. We also predicted that training would transfer to the 2D drawing task. However, the pre-training performance of both younger and older children was equally poor. Nevertheless, post-training performance on the 3D task was dramatically improved for both age groups and the training transferred to the 2D drawing task. Overall, this work contributes to a growing body of literature that demonstrates relatively preserved motor learning in children with motor difficulties and further demonstrates the importance of games in therapeutic interventions.     

The role of movement speed in learning a visuo-manual coordination in children

Summary The aim of the present study was to investigate the processes underlying aiming movements (motor programming and feedback control), and to explore their modification through learning. Two groups of 6- and 9-year-old children were asked to perform a directional aiming task without visual feedback (open-loop situation). After 15 trials (pretest) all subjects were submitted to a practice session which consisted of three series of trials with visual feedback (closed-loop situation). Half of the subjects had to perform the task at maximum speed (programmed movements), while the other half was required to perform slow movements (feedback-controlled movements). After the practice session all subjects were tested again in the openloop situation without time constraints (posttest). The results showed that during the practice session, accuracy was greater than in the two test conditions. It was greater in the case of slow movements than in the case of rapid ones. Moreover, in the case of rapid movements, it did not improve over the three practice series, while it did improve with slow movements. The difference between pre- and posttests showed that both groups improved their accuracy with practice in all conditions, the greatest improvement being obtained with rapid practice movements in 9-year-old children. It is suggested that different types of feedback (on-line and delayed feedback) contribute in varying degrees to the improvement of the aiming movements. However, the rapid movement condition, which requires a greater efficiency of programming, was found to be more effective for learning than the slow movement condition. The age-related differences found in learning suggest that feedback information can be fully integrated into motor programming only after 6 years of age.     

Effects of receptive language training on receptive and expressive language development

The effects of a six-month training program in receptive language on receptive and expressive language development were investigated. Developmentally retarded preschoolers were pretested and posttested on one standardized test of receptive language and two tests of expressive language. Both the training and control groups participated in a preschool program. In addition, the training group received a two-sequence training program: (1) reinforcement for matching responses to modeling cues and accompanying verbal requests, and (2) reinforcement for appropriate responses to verbal requests alone. The training group demonstrated a significant increase in appropriate responses to verbal request over base-rate performance after the training and also demonstrated a significantly improved posttest performance on one test of expressive language as compared to the control group.The authors wish to thank Mrs. Helen Huggins and the staff of the Aid to Retarded Children's Preschool Training Center, San Francisco, California, for their assistance in this study. A modified version of this paper was presented at the Gatlinburg Conference on Mental Retardation, March, 1974, Gatlinburg, Tennessee.     

Increasing the distance of an external focus of attention enhances learning

Previous studies (e.g., Wulf, H?ss, & Prinz, 1998) have shown that motor learning can be enhanced by directing performers' attention to the effects of their movements ("external focus"), rather than to the body movements producing the effect ("internal focus"). The purpose of the present study was to test the hypothesis that increasing the distance between the body and the action effects might further enhance the learning advantages associated with an external focus of attention. The distance of the external effect was manipulated by instructing three groups of participants learning to balance on a stabilometer to focus on markers attached to the platform located at different distances from their feet. Specifically, two groups were to focus on distant markers on the outside ("far-outside") or inside ("far-inside") of the platform, respectively, whereas another group was instructed to focus on markers close to their feet ("near"). In a retention test administered after two days of practice, all three external-focus groups showed generally more effective balance learning than an internal-focus control group. In addition, the far-outside and far-inside groups demonstrated similar performances, and both were more effective than the near group. Furthermore, the far-outside and far-inside groups showed higher-frequency movement adjustments than the near group. These results suggest that focusing on more distant effects results in enhanced learning by promoting the utilization of more natural control mechanisms. The findings are in line with a "constrained action" hypothesis that accounts for the relatively poorer learning associated with an attentional focus directed towards effects in close proximity to the body, or towards the body itself.     

Practice effects on motor control in healthy seniors and patients with mild cognitive impairment and Alzheimer's disease

This research was designed to test the hypothesis that motor practice can enhance the capabilities of motor control in healthy controls (NC) and patients with a diagnosis of probable Alzheimer's disease (AD) and mild cognitive impairment (MCI), and consequently results in better motor performance. Approximately half of the subjects in the NC (n = 31), AD (n = 28), and MCI (n = 29) either received or did not receive practice on a task of fast and accurate arm movement with a digitizer. Changes in movement time (MT), movement smoothness (jerk), and percentage of primary submovement (PPS) were recorded and compared among the three groups across six blocks of trials (baseline and five training sessions). For all subjects, practice improved motor functions as reflected by faster and smoother motor execution, as well as a greater proportion of programming control. Compared to unaffected matched controls, AD and MCI subjects exhibited a greater reduction in movement jerk due to practice. Movement time and PPS data revealed that motor practice appeared to reduce the use of "on-line" correction adopted by the AD or MCI patients while performing the aiming movements. Evidently, their arm movements were quicker, smoother, and temporally more consistent than their untrained peers. The findings of this study shed light on how MCI and AD may affect motor control mechanisms, and suggest possible therapeutic interventions aimed at improving motor functioning in these impaired individuals.     

Co-regulation of movement speed and accuracy by children with heavy prenatal alcohol exposure

The study investigated how children with heavy prenatal alcohol exposure regulate movement speed and accuracy during goal-directed movements. 16 children ages 7 to 17 years with confirmed histories of heavy in utero alcohol exposure, and 21 nonalcohol-exposed control children completed a series of reciprocal tapping movements between two spatial targets. 5 different targets sets were presented, representing a range of task difficulty between 2 and 6 bits of information. Estimates of percent error rate, movement time, slope, and linear fit of the resulting curve confirmed that for goal-directed, reciprocal tapping responses, performance of the group with prenatal alcohol exposure was described by a linear function, as predicted by Fitts' law, by sacrificing movement accuracy. The index of performance was the same for the two groups: it initially increased, then leveled off for more difficult movements.     

Variability in practice: facilitation in retention and transfer through schema formation or context effects?

The main purpose of the study was to examine whether the effects of variability in practice within a class of movements, that is, enhanced retention and transfer performance relative to constant practice, are due to the formation of motor schemata (Schmidt, 1975) or to contextual interference effects, as suggested by Lee, Magill, and Weeks (1985). Forty-eight subjects were tested on a sequential timing task. One group of subjects (Schema) received variable practice within one movement class, practicing the same phasing pattern with different absolute durations. Practice conditions of another group (Context) involved the same absolute movement durations, as well as a different phasing pattern for each task version. Thus, contextual interference was about the same for both groups but only one group experienced different movement variations of the same class. On a retention test performed on a task version that had been practiced by both groups before as well as on a transfer test with the same phasing pattern but a longer absolute duration, the Schema group performed more effectively than the Context group, thus supporting schema theory. On a transfer task with new phasing requirements, however, the Context group demonstrated performance superior to that of the Schema group. In this case, the Context practice condition seemed to be more transfer-appropriate.     

Fine motor deficiencies in children diagnosed as DCD based on poor grapho-motor ability

A sample of 125 children from grades 4 and 5 of two normal Dutch primary schools were investigated regarding the incidence of handwriting problems and other fine motor disabilities. Handwriting quality was assessed with the concise assessment method for children's handwriting (BHK) and the school questionnaire for teachers (SQT). Two groups of 12 children each were formed, one group of good writers and a group of poor writers selected from the lower performance range. The latter group was investigated in depth by assessing general and fine motor ability using the Movement Assessment Battery for Children (M-ABC test) and the Motor Performance School Readiness Test (MSRT). We hypothesised that poor handwriting is part of a wider neuromotor condition characterised by faster and cruder movements, lack of inhibition of co-movements and poor co-ordination of fine motor skills. To test the theory kinematic measures of drawing movements were collected on the flower-trail-drawing item of the M-ABC test. Moreover, the experimental group of poor writers received physiotherapy during a three-month period and was tested for handwriting proficiency after therapy and again nine months later. The results revealed that 34% of the group of 125 children displayed handwriting problems. The analysis confirmed that serious handwriting problems are accompanied by fine motor deficits. We suggest that in these children an enhanced level of neuromotor noise is compensated for by enhanced phasic stiffness of the limb system. This results in higher movement velocity and fewer velocity peaks. In the children who received physiotherapy the quality of handwriting improved.     

Are the predictions of the dynamic dominance model of laterality applicable to the lower limbs?

Investigation of manual actions has supported the proposition that the right and left cerebral hemispheres have complementary specializations relevant for movement control. To test the extent to which hemisphere specialization affect lower limb control, we compared performance between the legs in two motor tasks. A pedal aiming task was employed to test the notion of left hemisphere specialization for dynamic control, and unipedal balance was employed to test the notion of right hemisphere specialization for impedance control. Evaluation was conducted on young adults, in the contexts of separate (Experiment 1) and integrated (Experiment 2) performance of the probing tasks. Results from the aiming task showed equivalent movement linearity toward the target between the right and left feet across experiments. Analysis of unipedal balance revealed that increased stance stability when supported on the left leg was observed when performing simultaneously the aiming task with the contralateral foot, but not in the context of isolated task performance. These results are inconsistent with the proposition of left hemisphere specialization for dynamic control in the lower limbs, and suggest that specialization of the right hemisphere for impedance control can be observed in balance control when stance is associated with voluntary movements of the contralateral lower limb.     

Accuracy of movement speed and error detection skills in adolescents with cerebral palsy.

People with cerebral palsy (CP) usually have decreased ability to learn new movements and decreased movement speed. This study examined the ability of 10 adolescents with CP (M age = 16.2 yr., SD = 1.9 yr.) to achieve a target speed on an tipper extremity ballistic task and to detect speed errors in their movements, compared to the performance of 10 adolescents with no disability (M age = 15.7 yr., SD = 1.7 yr.). Subjects were instructed to slide a lever along a track in 150 msec., then guess their movement time. Knowledge of results feedback was provided on the first 50 trials except for Trials 11-20 on Day 1. Knowledge of results feedback was withheld on Day 2, Trials 51-60, to assess learning and retention of the skill. Speed Error and Error Detection were compared for two groups of adolescents on Trials 51-60. Independent t tests indicated a significant difference between the two groups for both Speed Error and Error Detection. Examination of individual scores of the adolescents with CP indicated that half scored within the range of the control group, and variability of skills within the group with CP was high. Some individuals with CP have deficits in accuracy of movement speed and error detection unrelated to their severity of CP which may affect their ability to learn new movements.     

Effects of aquatic training on swimming skill development of preschool children

This research investigated the effects of aquatic training on the swimming performance of 126 children, ages 2.5 to 5.5 yr., over 8 mo. Two groups of children were enrolled in an aquatic training program. Group 1 were returning program participants at the beginning of this study, and Group 2 were new participants. The control children (Group 3) received no aquatic training during the research. Subjects performed six categories of swimming tasks at three points in time--1st mo., 4th mo., and 8th mo. The categories were Locomotion: Front, Locomotion: Back, Kicking, Entry: Jump, Diving, and Ring Pick-up. A 2 X 3 X 2 X 3 (sex X group X age X time) repeated-measures analysis of variance procedure showed that returning participants performed each category of swimming tasks at a more advanced level than the other groups at each time of measurement. New participants after training performed five of the categories of tasks at a more advanced level than the control group. Amount of training significantly influenced swimming, and training effects were task-specific when data were interpreted in terms of specific movement characteristics.