Knowledge of Results for Motor Learning: Relationship Between Error Estimation and Knowledge of Results Frequency

The authors of the present study investigated the apparent contradiction between early and more recent views of knowledge of results (KR), the idea that how one is engaged before receiving KR may not be independent of how one uses that KR. In a 2 × 2 factorial design, participants (N = 64) practiced a simple force-production task and (a) were required, or not required, to estimate error about their previous response and (b) were provided KR either after every response (100%) or after every 5th response (20%) during acquisition. A no-KR retention test revealed an interaction between acquisition error estimation and KR frequencies. The group that received 100% KR and was required to error estimate during acquisition performed the best during retention. The 2 groups that received 20% KR performed less well. Finally, the group that received 100% KR and was not required to error estimate during acquisition performed the poorest during retention. One general interpretation of that pattern of results is that motor learning is an increasing function of the degree to which participants use KR to test response hypotheses (J. A. Adams, 1971; R. A. Schmidt, 1975). Practicing simple responses coupled with error estimation may embody response hypotheses that can be tested with KR, thus benefiting motor learning most under a 100% KR condition. Practicing simple responses without error estimation is less likely to embody response hypothesis, however, which may increase the probability that participants will use KR to guide upcoming responses, thus attenuating motor learning under a 100% KR condition. The authors conclude, therefore, that how one is engaged before receiving KR may not be independent of how one uses KR.     

Reduced-Frequency Concurrent and Terminal Feedback: A Test of the Guidance Hypothesis

In 2 experiments, the authors manipulated the frequency of concurrent feedback to discern the effects on learning. In each experiment, participants (N = 48, Experiment 1; N = 36, Experiment 2) attempted to reproduce a criterion force-production waveform (5 s in duration) presented on the computer monitor. Consistent with the guidance hypothesis, the results of Experiment 1 indicated very strong guiding effects of concurrent feedback and strong dependence on the feedback, as indicated by participants' extremely poor performance upon feedback withdrawal in retention. As predicted by the guidance hypothesis, dependence on the feedback was reduced as a result of reducing the frequency of the concurrent feedback. The results of Experiment 2 indicated that one can enhance learning by providing concurrent and terminal feedback on 1 trial, with no feedback on the subsequent trial. In that way, the strong guiding effects of concurrent feedback could be realized and the beneficial effects of terminal feedback could also be achieved.     

Intentional Teaching Facilitates Young Children's Comprehension and Use of a Symbolic Object

Children are exposed to symbolic objects that they have to learn to use very early in life. The authors’ aim was to examine whether it is possible to intentionally teach young children the symbolic function of an object. They employed a search task in which children had to use a map to find a toy. Experiment 1 revealed that with no instruction 3-year-, 10-month-old children were quite successful; 3-year-, 6-month-olds showed a divided performance; and 3-year-, 0-month-olds failed. With this baseline, Experiment 2 compared the performance of 3-year-, 0-month-olds in three different conditions: no-instruction, complete instruction (before the task begins), and teaching (complete instruction plus corrective feedback); only children in the teaching condition succeeded. However, children 6 months younger, 2-year-, 6-month-olds, failed despite teaching that was provided (Study 3). This research shows that at some points in development instruction is not enough; intentional teaching in communicative contexts is the mechanism that boosts symbolic understanding in early childhood.     

The Impact of Real and Illusory Perturbations on the Early Trajectory Adjustments of Goal-Directed Movements

Examinations of goal-directed movements reveal a process of control that operates to make adjustments on the basis of the expected visual afference associated with the limb's movement. This experiment examined the impact of perturbations to the perceived and actual velocity of aiming movements when each was presented alone or in tandem with the other. Perturbations to perceived velocity were achieved by translating the background over which aiming movements were performed. An aiming stylus that discharged air either in the direction of the movement or in the direction opposite the movement generated the actual velocity perturbations. Kinematic analyses of the aiming movements revealed that only the actual perturbation influenced the control of early movement trajectories. The results are discussed with respect to the influence that visual information has on the control exerted against physical perturbations. Speculations are raised regarding how potential for perturbations influences the strategies adopted for minimizing their impact.     

Memory and Perceptual Trace Development in Ballistic Timing

Adams’ (1971) closed-loop theory holds that memory and perceptual trace development is a function of the amount of practice with knowledge of results. If knowledge of results is withdrawn before these two memory states are strong performance will worsen, but after substantial practice performance can be maintained and evaluated in the absence of knowledge of results. To test the first prediction, three independent groups were given varying amounts of KR trials prior to early knowledge of results withdrawal. Subjects attempted to produce a 24.13-cm movement in exactly 150 msec. Memory and perceptual trace performance (as reflected in mean absolute and mean absolute estimated error, respectively) were dependent on the amount of knowledge of results practice, and the memory and perceptual trace remained reasonably strong during late knowledge of results withdrawal.     

Visual and Proprioceptive Determinants of Space Perception and Movement

The present study determined the relationship between perception of the upright in 2-dimensional space and movement accuracy. 161 female Ss were administered the Rod and Frame Test, and 30 Ss, whose scores indicated the greatest and least error in perceptual differentiation, were assigned to 2 experimental groups and measured on accuracy of postural pursuit tracking. The effects of direction of movement and visual field conditions on accuracy of performance were determined by a coordinate postural platform and hybrid computer methods. A direct relationship existed between perception of the vertical in space and accuracy of motor responses and that perceptual integration was affected by the direction of movement and the presence of a stable visual field.     

Specificity of Learning in a Video-Aiming Task: Modifying the Salience of Dynamic Visual Cues

The authors investigated whether the salience of dynamic visual information in a video-aiming task mediates the specificity of practice. Thirty participants practiced video-aiming movements in a full-vision, a weak-vision, or a target-only condition before being transferred to the target-only condition without knowledge of results. The full- and weak-vision conditions resulted in less endpoint bias and variability in acquisition than did the target-only condition. Going from acquisition to transfer resulted in a large increase in endpoint variability for the full-vision group but not for the weak-vision or target-only groups. Kinematic analysis revealed that weak dynamic visual cues do not mask the processing of other sources of afferent information; unlike strong visual cues, weak visual cues help individuals calibrate less salient sources of afferent information, such as proprioception.     

Correction of a Technical Error in the Golf Swing: Error Amplification Versus Direct Instruction

Performance errors drive motor learning for many tasks. The authors' aim was to determine which of two strategies, method of amplification of error (MAE) or direct instruction (DI), would be more beneficial for error correction during a full golfing swing with a driver. Thirty-four golfers were randomly assigned to one of three training conditions (MAE, DI, and control). Participants were tested in a practice session in which each golfer performed 7 pretraining trials, 6 training-intervention trials, and 7 posttraining trials; and a retention test after 1 week. An optoeletronic motion capture system was used to measure the kinematic parameters of each golfer's performance. Results showed that MAE is an effective strategy for correcting the technical errors leading to a rapid improvement in performance. These findings could have practical implications for sport psychology and physical education because, while practice is obviously necessary for improving learning, the efficacy of the learning process is essential in enhancing learners' motivation and sport enjoyment.     

Sensory Integration and Response to Balance Perturbation in Overweight Physically Active Individuals

The purpose of this study was to compare sensory integration and response to balance perturbation between physically active normal weight and overweight adults. Physically active young adults were grouped into normal weight (n = 45) or overweight (n = 17) according to the World Health Organization body mass index classification for Asian adults. Participants underwent two balance tests: sensory organization and motor control. Overweight participants presented marginally lower somatosensory score compared to normal weight participants. However, they scored significantly higher in response to balance perturbation. There was no difference in the onset of participants' active response to balance perturbation. Physical activity might have contributed to improved muscle strength and improved the ability of overweight individuals to maintain balance.     

Work and Rest Variables in the Acquisition of Psychomotor Tracking Skill

College students (75 men, 75 women) matched in preliminary performance of 100 sec on the rotary pursuit apparatus were randomly assigned to five experimental groups. Their work/rest ratios, measured in seconds, were: 20/20, 30/30, 60/60, 90/90,120/120. All subjects received 30 min of total practice time after the matching trial. There was a significant practice effect and a significant practice x conditions interaction, but no main effect due to the cycles’ length or number. The decay rate of reactive inhibition (lr) is probably independent of its prior growth level; hence postrest residual lr is proportional to prerest accumulation. Partly because they generated lr in hypothetically greater amounts, women were significantly less proficient on the average than men, and sex interacted with practice. Although males had higher initial and final levels of ability than females, the two sexes’ acquisition curves showed the same rate parameters in our mathematical model.