Learning a complex motor skill from video and point-light demonstrations

The aim of this study was to compare the learning process of a highly complex ballet skill following demonstrations of point-light and video models. 16 participants divided into point-light and video groups (ns = 8) performed 160 trials of a pirouette, equally distributed in blocks of 20 trials, alternating periods of demonstration and practice, with a retention test a day later. Measures of head and trunk oscillation, coordination disparity from the model, and movement time difference showed similarities between video and point-light groups; ballet experts' evaluations indicated superiority of performance in the video over the point-light group. Results are discussed in terms of the task requirements of dissociation between head and trunk rotations, focusing on the hypothesis of sufficiency and higher relevance of information contained in biological motion models applied to learning of complex motor skills.     

Subjects' skill and biphasic effects of met-enkephalin upon the acquisition and retention of a perceptual motor task

The effects of met-enkephalin on the acquisition and retention over 10 days of a perceptual motor skill were investigated. Mice were randomly assigned to either one of two experimental groups (1-mg or 3-mg injections per 1-kg of body weight of met-enkephalin) or one of two control groups (dH2O injections). During the acquisition phase of the study, they were separated into "slow" and "fast" learners on the basis of their skill in negotiating a water maze. The results indicated an inhibitory effect of met-enkephalin in the 3-mg condition in the retention phase of the experiment. Subjects' skill was not implicated as a critical factor in retention of this simple task.     

A microcomputer-based tracking task for examination of the spatial and temporal organization of perceptual motor skill

A microcomputer-based tracking task is described in detail. The program that controls this task was written in Pascal and 6502 assembler language and was designed to run on an Apple IIe computer. The program was designed to allow the experimenter to vary such parameters as the velocity of the stimulus signal. In addition, several indicants of performance are recorded simultaneously and are averaged over selected time intervals during each trial. The paper also illustrates the applications of this particular computer program in the study of motor control and learning.     

Subjective time and perceptual skill

Subjective time estimation was hypothesized as correlated with the number of discrete events one discerns per interval and one's attentiveness, interest in the experience, and efficiency. It was predicted that one who recognizes many discrete events per interval and rates high on these personality traits tends to underestimate time. For personality attributes, tapped by questionnaire, high scores denote an individual who shows the predicted characteristics of underestimaters. Estimations were made of a 3-min. tone of 191 Hz by 40 college men. Pearson correlation between questionnaire scores and time estimates was -.30. All 8 subjects with scores below 100 overestimated.     

Attentional demands following perceptual skill training

Practicing simple visual tasks induces substantial improvement. We investigated whether increased efficiency is accompanied by automaticity and immunity to across-task interference. We found that although practice speeds orientation feature detection, it does not abolish susceptibility to interference from introduction of concurrent central-letter identification, which takes priority. Yet following training with each task, observers successfully managed to perform the tasks concurrently. The effectiveness of separate training implies that the role of improved intertask coordination in achieving concurrent performance was minor. Indeed, even when initial training was concurrent, improvement on the two tasks was sequential, and the higher-priority (central) task was learned first. However, automatic processing was not accomplished either, because increasing the difficulty of the higher-priority task interfered with performance of both tasks. What appears to be orchestrated posttraining performance is actually mainly an emergent property of speeded initial processes rather than either eliminated bottlenecks or improved central executive management.     

H-reflexes during a motor skill acquisition task

H-reflex amplitudes were studied during the acquisition of a motor skill involving coordinated isometric plantarflexion at the ankle joints as subjects learned to trace a triangular pattern on an oscilloscope screen by controlling plantarflexion torque applied against load cells. Torque feedback was presented on a subject oscilloscope with the right foot controlling a vertical cursor and the left foot a horizontal cursor. Eleven subjects reached criterion performance. H-reflexes were recorded from the right soleus and timed to the initiation of soleus muscle activity to plantarflex the foot. Average time to complete one trial decreased from 9 sec. in the prelearning block to 4 sec. postlearning. No single learning strategy was evident as subjects varied widely in their levels of H-reflex amplitude, but during postlearning, H-reflex amplitude became consistent within subjects as tracing performance became faster and accurate.     

Self-controlled concurrent feedback and the education of attention towards perceptual invariants

The present study investigates the effects of different types of concurrent feedback on the acquisition of perceptual-motor skills. Twenty participants walked through virtual corridors in which rhythmically opening and closing sliding doors were placed. The participants aimed to adjust their walking speed so as to cross the doors when the doors were close to their maximal aperture width. The highest level of performance was achieved by learners who practiced the task with unambiguous self-controlled concurrent feedback, which is to say, by learners who could request that feedback at wish. Practice with imposed rather than self-controlled feedback and practice without concurrent feedback were shown to be less effective. Finally, the way in which the self-controlled concurrent feedback was presented was also found to be of paramount importance; if the feedback is ambiguous, it may even prevent participants from learning the task. Clearly, unambiguous self-controlled feedback can give rise to higher levels of performance than other feedback conditions (compared to imposed schedule) but, depending on the way it is presented, the feedback can also prevent the participants from learning the task.In the discussion it is argued that unambiguous self-controlled concurrent feedback allows learners to more rapidly educate their attention towards more useful perceptual invariants and to calibrate the relation between perceptual invariants and action parameters.     

Action-dependent perceptual invariants: from ecological to sensorimotor approaches

Ecological and sensorimotor theories of perception build on the notion of action-dependent invariants as the basic structures underlying perceptual capacities. In this paper we contrast the assumptions these theories make on the nature of perceptual information modulated by action. By focusing on the question, how movement specifies perceptual information, we show that ecological and sensorimotor theories endorse substantially different views about the role of action in perception. In particular we argue that ecological invariants are characterized with reference to transformations produced in the sensory array by movement: such invariants are transformation-specific but do not imply motor-specificity. In contrast, sensorimotor theories assume that perceptual invariants are intrinsically tied to specific movements. We show that this difference leads to different empirical predictions and we submit that the distinction between motor equivalence and motor-specificity needs further clarification in order to provide a more constrained account of action/perception relations.     

Becoming aware of motor skill

Conscious processes have a complex relationship to skilled motor performance. Past work has shown that some types of motor skill can be learned without any contribution from conscious processes. New work indicates that if those unconscious processes are disabled, conscious processes might step in to make up for the deficit.     

Scaling a motor skill through observation and practice

The authors examined the proposal that a motor skill is scaled through physical practice and not through observation of a model. In 4 groups, participants (N = 32) did or did not imitate a model bowling a ball to a target 8 m away. In an assessment phase, those groups did or did not observe the same model bowling a ball to a target 4 m away. Participants who viewed a model in the assessment phase were more accurate and consistent in terms of bowling accuracy than were those who did not. Their shoulder and wrist velocity profiles were more similar to those of the 4-m model than were those of the no-model group. Participants who had previous practice and viewed a demonstration were more accurate at scaling the wrist of the bowling arm. Observing a demonstration facilitates the acquisition of control-related features of a movement. Furthermore, early acquisition of coordination aids the use of velocity information for scaling the endpoint of the primary effector.     

Configural response learning: the acquisition of a nonpredictive motor skill

This study examined the representational nature of configural response learning using a task that required simultaneous keypresses with 2 or 3 fingers, similar to the production of chords on the piano. If the benefits of learning are related to the retrieval of individual stimulus-response mappings, performance should depend on the frequencies of the individual responses forming each chord. Alternatively, learning may involve the encoding of configural information concerning the relationship between the chord elements. In Experiment 1, training was restricted to a subset of the 120 possible 3-element chords. Probe blocks included the practiced chords, chords composed of novel configurations of practiced elements (reconfigured), and chords that contained a new element (new). Practiced chords were performed faster than reconfigured chords, indicating learning involves the encoding of configural information. Experiment 2 showed that learning was not restricted to configurations within each hand. Experiments 3 and 4 demonstrated that learning was largely response based.     

Speech motor skill and stuttering

The authors review converging lines of evidence from behavioral, kinematic, and neuroimaging data that point to limitations in speech motor skills in people who stutter (PWS). From their review, they conclude that PWS differ from those who do not in terms of their ability to improve with practice and retain practiced changes in the long term, and that they are less efficient and less flexible in their adaptation to lower (motor) and higher (cognitive-linguistic) order requirements that impact on speech motor functions. These findings in general provide empirical support for the position that PWS may occupy the low end of the speech motor skill continuum as argued in the Speech Motor Skills approach (Van Lieshout, Hulstijn, & Peters, 2004).     

Context-dependent motor skill and the role of practice

Research has shown that retrieval of learned information is better when the original learning context is reinstated during testing than when this context is changed. Recently, such contextual dependencies have also been found for perceptual-motor behavior. The current study investigated the nature of context-dependent learning in the discrete sequence production task, and in addition examined whether the amount of practice affects the extent to which sequences are sensitive to contextual alterations. It was found that changing contextual cues-but not the removal of such cues-had a detrimental effect on performance. Moreover, this effect was observed only after limited practice, but not after extensive practice. Our findings support the notion of a novel type of context-dependent learning during initial motor skill acquisition and demonstrate that this context-dependence reduces with practice. It is proposed that a gradual development with practice from stimulus-driven to representation-driven sequence execution underlies this practice effect.