The transfer of movement sequences: effects of decreased and increased load

A number of recent experiments have demonstrated that a movement structure develops during the course of learning a movement sequence that provides the basis for transfer. After learning a movement sequence participants have been shown to be able to effectively produce the sequence when movement demands require that the sequence be rescaled in amplitude or produced with an unpractised set of effectors. The purpose of the present experiment was to determine whether participants, after learning a complex 16-element movement sequence with a 0.567-kg load, could also effectively produce the sequence when the load was decreased (0.0 kg) or increased (1.134 kg). The results indicated that participants were able to effectively compensate for decreased and increased load with virtually no changes in performance characteristics (displacement, velocity, acceleration, and pattern of element durations) while electromyographic (EMG) signals demonstrated that smaller (reduced load) or larger forces (increased load) were spontaneously generated to compensate for the change in load. The muscle activation patterns of the biceps and triceps as well as the level of coactivation appeared to be generally upscaled to generate and dissipate the changes in force requirement needed to compensate for the increased load.     

The role of eye movements in motor sequence learning

An experiment that utilized a 16-element movement sequence was designed to determine the impact of eye movements on sequence learning. The participants were randomly assigned to two experimental groups: a group that was permitted to use eye movements (FREE) and a second group (FIX) that was instructed to fixate on a marker during acquisition (ACQ). A retention test (RET) was designed to provide a measure of learning, and two transfer tests were designed to determine the extent to which eye movements influenced sequence learning. The results demonstrated that both groups decreased the response time to produce the sequence, but the participants in the FREE group performed the sequence more quickly than participants of the FIX group during the ACQ, RET and the two transfer tests. Furthermore, continuous visual control of response execution was reduced over the course of learning. The results of the transfer tests indicated that oculomotor information regarding the sequence can be stored in memory and enhances response production.     

Exploring the kinaesthetic sensitivity of skilled performers for implementing movement instructions

The capability to effectively control or adapt a movement pattern based on instructional feedback is essential for effective motor skill learning in high-level sport, as it is in other domains such as rehabilitation or music. Despite this, little is known about the capabilities of skilled athletes to use kinematic feedback to purposefully modify complex movements. This study examined the accuracy with which skilled junior tennis players could translate specific kinematic feedback into appropriate modifications of their service actions. Participants were required to either increase or decrease maximum knee flexion or shift impact position laterally by incremental amounts. Further, participants were required to execute their serve with the smallest increase and decrease in these kinematic components as they could consciously produce. Inherent variability within the desired target parameters was calculated to add context to the athlete’s accuracy. Results demonstrated that while participants had considerable control over their movements, only some instructions were executed with accuracy greater the variability normally present within their movement. As the required change in knee flexion and impact position increased, absolute accuracy of implementation decreased. These findings are discussed with reference to the smallest controllable changes produced by the athletes and the variability within their actions.     

Re-examining the effects of verbal instructional type on early stage motor learning

The present study investigated the differential effects of analogy and explicit instructions on early stage motor learning and movement in a modified high jump task. Participants were randomly assigned to one of three experimental conditions: analogy, explicit light (reduced informational load), or traditional explicit (large informational load). During the two-day learning phase, participants learned a novel high jump technique based on the ‘scissors’ style using the instructions for their respective conditions. For the single-day testing phase, participants completed both a retention test and task-relevant pressure test, the latter of which featured a rising high-jump-bar pressure manipulation. Although analogy learners demonstrated slightly more efficient technique and reported fewer technical rules on average, the differences between the conditions were not statistically significant. There were, however, significant differences in joint variability with respect to instructional type, as variability was lowest for the analogy condition during both the learning and testing phases, and as a function of block, as joint variability decreased for all conditions during the learning phase. Findings suggest that reducing the informational volume of explicit instructions may mitigate the deleterious effects on performance previously associated with explicit learning in the literature.     

Influence of Speed and Accuracy Constraints on Motor Learning for a Trajectory-Based Movement

This study investigated the influences of task constraint on motor learning for a trajectory-based movement considering the speed–accuracy relationship. In the experiment, participants practiced trajectory-based movements for five consecutive days. The participants were engaged in training with time-minimization or time-matching constraints. The results demonstrated that the speed–accuracy tradeoff was not apparent or was weak in the training situation. When the participants practiced the movement with a time-minimization constraint, movement errors did not vary, whereas the movement time decreased. With the time-matching constraint, the errors decreased as a session proceeded. These results were discussed in terms of the combination of signal-dependent noises and exploratory search noises. It is suggested that updating spatial and temporal factors does not appear to occur simultaneously in motor learning.     

Randomised controlled pilot trial of mindfulness training for stress reduction during pregnancy

This randomised controlled pilot trial tested a six-week mindfulness-based intervention in a sample of pregnant women experiencing high levels of perceived stress and pregnancy anxiety. Forty-seven women enrolled between 10 and 25 weeks gestation were randomly assigned to either a series of weekly Mindful Awareness Practices classes (n = 24) with home practice or to a reading control condition (n = 23). Hierarchical linear models of between-group differences in change over time demonstrated that participants in the mindfulness intervention experienced larger decreases from pre-to post-intervention in pregnancy-specific anxiety and pregnancy-related anxiety (PRA) than participants in the reading control condition. However, these effects were not sustained through follow-up at six weeks post-intervention. Participants in both groups experienced increased mindfulness, as well as decreased perceived stress and state anxiety over the course of the intervention and follow-up periods. This study is one of the first randomised controlled pilot trials of a mindfulness meditation intervention during pregnancy and provides some evidence that mindfulness training during pregnancy may effectively reduce PRA and worry. We discuss some of the dilemmas in pursuing this translational strategy and offer suggestions for researchers interested in conducting mind-body interventions during pregnancy.     

Implicit sequence learning in a continuous pursuit-tracking task

Assessing implicit learning in the continuous pursuit-tracking task usually concerns a repeated segment of target displacements masked by two random segments, as referred to as Pew’s paradigm. Evidence for segment learning in this paradigm is scanty and contrasts with robust sequence learning in discrete tracking tasks. The present study investigates this issue with two experiments in which participants (N = 56) performed a continuous tracking task. Contrary to Pew’s paradigm, participants were presented with a training sequence that was continuously cycled during 14 blocks of practice, but Block 12 in which a transfer sequence was introduced. Results demonstrate sequence learning in several conditions except in the condition that was obviously the most similar to previous studies failing to induce segment learning. Specifically, it is shown here that a target moving too slowly combined with variable time at which target reversal occurs prevents sequence learning. In addition, data from a post-experimental recognition test indicate that sequence learning was associated with explicit perceptual knowledge about the repetitive structure. We propose that learning repetition in a continuous tracking task is conditional on its capacity to (1) allow participants to detect the repeated regularities and (2) restrict feedback-based tracking strategies.     

Autonomy facilitates repeated maximum force productions

Performer autonomy (or self-control) has consistently been shown to enhance motor learning, and it can also provide immediate benefits for motor performance. Autonomy is also a key variable in the OPTIMAL theory of motor learning (Wulf & Lewthwaite, 2016). It is assumed to contribute to enhanced expectancies and goal-action coupling, affecting performance effectiveness and efficiency. The purpose of the present study was to examine whether providing autonomy support by giving performers choices would enhance their ability to maintain maximum force levels. Participants were asked to repeatedly produce maximum forces using a hand dynamometer. After 2 initial trials with the dominant and non-dominant hand, stratified randomization was used to assign participants with the same average maximum force to one of two groups, choice or yoked control groups. Choice group participants were able to choose the order of hands (dominant, non-dominant) on the remaining trials (3 per hand). For control group participants, hand order was determined by choice-group counterparts. Maximum forces decreased significantly across trials in the control group, whereas choice group participants were able to maintain the maximum forces produced on the first trial. We interpret these findings as evidence that performer autonomy promotes movement efficiency. The results are in line with the view that autonomy facilitates the coupling of goals and actions (Wulf & Lewthwaite, 2016).     

注意负荷对内隐序列学习的影响研究

运用次级任务研究范式,采用符号计数的次级任务和歧义序列中的次级条件序列,将内隐序列学习分为单任务组和双任务组,统一在单任务条件下测试。结果发现:(1)两组被试内隐学习成绩差异不显著;(2)双任务组被试在学习组块和测试组块的内隐学习差异也不显著。结果进一步支持了在次级任务占用注意资源的条件下内隐学习仍然可以正常地获得、内隐序列学习不受注意负荷影响的观点。     

Separate movement planning and spatial assimilation effects in sequential bimanual aiming movements

This study extended earlier work by showing spatial assimilations in sequential bimanual aiming movements when the participant preplanned only the first movement of a two-movement sequence. Right-handed participants (n=20, aged 18 to 22 years) made rapid lever reversals of 20 degrees and 60 degrees singly and sequentially with an intermovement interval of 2.5 sec. Following blocked single practice of both movements in each hand (15 trials each), two sets of 30 sequential practice trials were completed. The sequences began with either the long or the short movement and the participant always knew the goal of the first movement. During the intermovement interval, the experimenter gave instructions to complete the sequence with a short movement, a long movement, or no movement in a random order. Compared to the single trials, both movements in the sequence overshot the short-distance and undershot the long-distance goal. Spatial errors increased when a change in the movement goal was required for the second movement in the sequence. The experiment demonstrated that separate planning of sequential aiming movements can reduce spatial assimilation effects, but interference due to practice organization and switching the task's goal must also be overcome in order to produce accurate aiming movements.     

Spatial assimilation effects in sequential movements: effects of parameter value switching and practice organization

In Experiment 1, the author extended earlier work by investigating spatial assimilations in sequential aiming movements when participants were able to preplan only the 1st movement of a 2-movement sequence. Right-handed participants (N = 20) aged 18-22 years tried unimanual rapid lever reversals of 20 degrees and 60 degrees with an intermovement interval of 2.5 s. Following the 1st movement, participants made a same-distance movement, different-distance movement, or no movement in a randomly determined order. Participants overshot the short-distance target and undershot the long-distance target for both movements in the sequence, but the errors were greater when the 2nd movement differed from the 1st one. In Experiment 2, right-handed participants (N = 20) demonstrated greater assimilation effects after random practice than after blocked practice of both same-distances (20 degrees -20 degrees and 60 degrees -60 degrees ) and different-distances (20 degrees -60 degrees and 60 degrees -20 degrees ) sequences, although spatial errors were greater in different-distances conditions than in same-distances conditions. Overall, the experiments showed that parameter-value switching and practice organization are 2 major sources of spatial inaccuracy in sequential aiming movements.     

Transfer of movement sequences: bigger is better

Experiment 1 was conducted to determine if proportional transfer from "small to large" scale movements is as effective as transferring from "large to small." We hypothesize that the learning of larger scale movement will require the participant to learn to manage the generation, storage, and dissipation of forces better than when practicing smaller scale movements. Thus, we predict an advantage for transfer of larger scale movements to smaller scale movements relative to transfer from smaller to larger scale movements. Experiment 2 was conducted to determine if adding a load to a smaller scale movement would enhance later transfer to a larger scale movement sequence. It was hypothesized that the added load would require the participants to consider the dynamics of the movement to a greater extent than without the load. The results replicated earlier findings of effective transfer from large to small movements, but consistent with our hypothesis, transfer was less effective from small to large (Experiment 1). However, when a load was added during acquisition transfer from small to large was enhanced even though the load was removed during the transfer test. These results are consistent with the notion that the transfer asymmetry noted in Experiment 1 was due to factors related to movement dynamics that were enhanced during practice of the larger scale movement sequence, but not during the practice of the smaller scale movement sequence. The findings that the movement structure is unaffected by transfer direction but the movement dynamics are influenced by transfer direction is consistent with hierarchal models of sequence production.     

Proportional and nonproportional transfer of movement sequences

Two experiments were designed to determine participants' ability to transfer a learned movement sequence to new spatial locations. A 16-element dynamic arm movement sequence was used in both experiments. The task required participants to move a horizontal lever to sequentially projected targets. Experiment 1 included 2 groups. One group practised a pattern in which targets were located at 20, 40, 60, and 80° from the start position (long sequence). The other group practised a pattern with targets at 20, 26.67, 60, and 80° (mixed sequence). Both groups were tested 24 hours later on the long, mixed, and short sequence. The short sequence was considered a proportional transfer for the long acquisition group because all the amplitudes between targets were reduced by the same proportion. Nonproportional transfer occurred when the amplitudes between targets did not have the same proportions as those for their practice sequence (e.g., long sequence to mixed sequence or vice versa). The results indicated that participants could effectively transfer to new target configurations regardless of whether the transfer required proportional or nonproportional spatial changes to the movement pattern. Experiment 2 assessed the effects of extended practice on proportional and nonproportional spatial transfer. The data indicated that while participants can effectively transfer to both proportional and nonproportional spatial transfer conditions after 1 day of practice, they are only effective at transferring to proportional transfer conditions after 4 days of practice. The results are discussed in terms of the mechanism by which response sequences become increasingly specific over extended practice in an attempt to optimize movement production.     

Effects of concurrent monitoring on cognitive load and performance as a function of task complexity

For self‐regulated learning to be effective, students or trainees need to be able to accurately monitor their performance while they are working on a task, use the outcomes as input for self‐assessment of that performance after completing the task and select an appropriate new learning task in response to that assessment. From a cognitive load perspective, monitoring can be seen as a secondary task that may become hard to maintain and hamper performance on the primary task under high load conditions. The experiment presented here investigated the effects of concurrent performance monitoring on cognitive load and performance as a function of task complexity. Results showed that monitoring significantly decreased performance and increased cognitive load on complex, but not on simple tasks. The findings are discussed in terms of theoretical consequences and instructional design for self‐regulated learning. Copyright © 2010 John Wiley & Sons, Ltd.     

内隐序列学习不受注意负荷的影响:来自眼动的证据

利用眼动记录方法,采用内隐序列学习的观察范式,通过操纵注意负荷高和低,考察内隐序列学习是否需要注意参与。结果发现:(1)在高、低注意负荷条件下都出现了内隐序列学习效应;(2)高注意负荷条件下眼跳反应时长于低注意负荷条件下的;(3)高、低注意负荷序列内隐序列学习量差异不显著,表明内隐序列学习不受注意负荷影响。     

The influence of visual flow and perceptual load on locomotion speed

Visual flow is used to perceive and regulate movement speed during locomotion. We assessed the extent to which variation in flow from the ground plane, arising from static visual textures, influences locomotion speed under conditions of concurrent perceptual load. In two experiments, participants walked over a 12-m projected walkway that consisted of stripes that were oriented orthogonal to the walking direction. In the critical conditions, the frequency of the stripes increased or decreased. We observed small, but consistent effects on walking speed, so that participants were walking slower when the frequency increased compared to when the frequency decreased. This basic effect suggests that participants interpreted the change in visual flow in these conditions as at least partly due to a change in their own movement speed, and counteracted such a change by speeding up or slowing down. Critically, these effects were magnified under conditions of low perceptual load and a locus of attention near the ground plane. Our findings suggest that the contribution of vision in the control of ongoing locomotion is relatively fluid and dependent on ongoing perceptual (and perhaps more generally cognitive) task demands.     

Scaling Judgments of Lifted Weight: Lifter Size and the Role of the Standard

Animals generally seek to avoid potentially harmful collisions. To perform successful avoidance, actors must correctly perceive the approach of an object and produce an appropriate motor response. Objects can approach from any part of the visual field, but avoidance skills are particularly relevant when threatening approaches occur in peripheral vision. This type of behavior has so far received little attention. Stoffregen and Riccio (1990) found that participants are sensitive to visually simulated impending collision at 0 or 90°. However, motor behavior produced in response to a real object approaching at various angles of eccentricity and at various speeds has not been investigated.

In this study, participants were asked to dodge a ball approaching at 0, 20, 40, 60, or 80° of eccentricity. The ball was travelling at a constant speed of 1.0, 1.5, or 2.0 m/sec. Results showed that time to contact (TTC) at initiation of the avoidant response was similar for 0 and 20° but increased from 20 to 80°. Angle of approach had no effect on participants' movement velocity. Ball speed had an effect on both variables. TTC decreased and participants' movement velocity increased with eccentricity. No interaction was observed between ball speed and eccentricity. These results show that a successful motor response to impending physical collision is possible across a wide range of approach eccentricities. It appears that the speed of the approach was accurately perceived. The speed of avoidant responses was consistent, suggesting that intensity coupling, that is, a coupling of movement velocity with stimulus speed, was not affected by the eccentricity.     

Time delays prior to movement alter the drawing kinematics of elderly adults

Position sense has been found to decay as a function of the time delay the limb remains in a static position prior to movement onset. Position sense has also been found to deteriorate as a function of aging, with increased reliance on vision by the elderly. This study investigated whether the pointing kinematics of elderly adults were differentially affected by delay compared to young adults, and whether visual information could compensate for the effects of delay. Young and elderly adults kept the limb in a static position for 1, 6, or 10 s prior to movement onset, both with and without vision of the limb, initial position, and the movement trajectory. Across groups, delay resulted in increased overall movement duration, decreased peak velocity including a shorter relative time to peak velocity, with decreased distance and duration of the primary submovement. Delay and lack of vision differentially decreased distance of the primary submovement for elderly adults. Vision was able to compensate to some degree for the effects of delay across age groups. The findings provide evidence that decays in position sense as a function of time create difficulties in incorporating the initial limb position in motor planning process in elderly adults.     

Differential allocation of study time: Incomplete compensation for the difficulty of the materials

The results of many experiments have shown that although people distribute their study time depending on the perceived difficulty of the materials, they do not succeed in compensating for this difficulty (e.g., Mazzoni & Cornoldi, 1993). The purpose of this paper was to explore possible ways to induce compensation. The objective difficulty of the items was varied by manipulating their concreteness. In Experiment 1, we explored whether compensation could be increased through practice. In Experiment 2, predictive memory judgements were obtained to determine to what extent participants were sensitive to the characteristics of the material that made it difficult. Finally, in Experiment 3, participants were given instructions designed to achieve complete compensation. Results showed that although participants' judgements of learning and their allocation of time were sensitive to the objective difficulty of the materials, this knowledge was not spontaneously used to compensate. Thus, even with practice participants recalled more easy items than difficult ones. Only instructions that induced greater awareness of the nature of the material were able to produce complete compensation.     

Differential allocation of study time: incomplete compensation for the difficulty of the materials

The results of many experiments have shown that although people distribute their study time depending on the perceived difficulty of the materials, they do not succeed in compensating for this difficulty (e.g., Mazzoni & Cornoldi, 1993). The purpose of this paper was to explore possible ways to induce compensation. The objective difficulty of the items was varied by manipulating their concreteness. In Experiment 1, we explored whether compensation could be increased through practice. In Experiment 2, predictive memory judgements were obtained to determine to what extent participants were sensitive to the characteristics of the material that made it difficult. Finally, in Experiment 3, participants were given instructions designed to achieve complete compensation. Results showed that although participants' judgements of learning and their allocation of time were sensitive to the objective difficulty of the materials, this knowledge was not spontaneously used to compensate. Thus, even with practice participants recalled more easy items than difficult ones. Only instructions that induced greater awareness of the nature of the material were able to produce complete compensation.