Retroactive interference effects of mentally imagined movement speed

In two retroactive interference experiments, we assessed the effect of mentally imagined movement speed on subsequent motor performance. All participants performed a sequential motor action at three speeds during a baseline test and a retention test. During the retention interval of Experiment 1, the participants (n = 50) physically performed the action at a slow speed, physically performed it at a fast speed, imagined it at a slow speed, imagined it at a fast speed, or performed a no-practice control task. In Experiment 2, the participants (n = 24) imagined the movement, overtly vocalized words, or both, all at a slow speed. The results revealed that the speed of the imagined motor action affected the speed of subsequent performance in the retention test and that imagery and physical practice were functionally equivalent. The results are consistent with Lang's bio-informational theory.     

The role of interference and task similarity on the acquisition, retention, and transfer of simple motor skills

The aim of the present study was to determine if two levels of task similarity influenced acquisition, retention, and transfer performance of three simple motor skills. Sixty right-handed subjects were randomly assigned to one of five (n = 12) experimental conditions. Each subject performed 72 trials during acquisition. Twenty-four trials were recorded for each movement task. Following a 5-min unfilled retention interval, subjects performed 4 trials on each task before completing 12 transfer trials of a novel movement. Contextual interference effects for acquisition and retention were supported for low but not high similarity tasks. Further, the results suggest that a different memory representation exists for high and low similarity tasks.     

双任务中内隐运动技能学习对提高保持成绩的作用

本实验研究的目的是,调查在双任务条件下一个运动系列能否被不觉察地掌握,内隐学习是否比外显学习更有效地增加保持.36名实验对象被随机分为内隐学习组或外显学习组.要求所有被试通过敲击一个键盘上的F和J键,来移动计算机屏幕上的横杆,去接住一个下落的小球.一个固定的5种小球下落曲线的系列被安插在每组15次练习的中段.同时,实验参加者需要数每组练习中的所听到的嘟嘟声的数目,以作为第二项任务.在掌握该技能后的24小时进行3次保持测验.ANOVA分析发现固定小球下落曲线段的接球成绩随着练习的增加而提高,但是练习对随机段没有作用.尽管两种练习条件下,运动技能学习成绩没有差异,但内隐学习组比外显学习组在模拟接球的保持测试和第二项任务中表现较准确.这些结果显示内隐学习是一个改善运动技能长期记忆的有效手段,并且与外显学习相比,它在练习中占用较少的认知资源.     

Motor expertise interacts with physical enactment to enhance action memory

Previous research on action memory showed the advantage for performing the action in memorising the action phrases. We tested if performing the action would help participants with or without motor expertise to memorise the novel action poses. Thirty novel action poses performed by an expert were photographed to constitute memory and interference stimuli. Eighty college students observed to remember the randomly displayed stimuli; however, half were asked to perform the displayed stimuli. Both free-recall and recognition tests were administered immediately and 24 h after the memory task. The results showed that acting was better than observing for memorising the novel action poses, which not only promoted the absolute retention but also alleviated the retention loss caused by interference. Motor expertise enhanced the overall memory performance by promoting a deeper motor encoding. Based on our results, novices should act with (rather than just observe) the model to learn novel motor skills.     

Enhancing motor learning through dyad practice: contributions of observation and dialogue

It has been shown that practice in dyads, as compared to individual practice, can enhance motor learning and increase the efficiency of practice (as two participants can be trained at the same time; Shea, Wulf, & Whitacre, 1999). The dyad practice protocol used by Shea et al. included both observation and dialogue between partners. Thus, it was not clear whether the learning benefits of dyad practice were due to observation, dialogue, or both. The present study examined the individual and interactive effects of observation and dialogue. The task used was speed cup stacking. Participants practiced under one of four conditions: observation/dialogue, observation/no dialogue, no observation/dialogue, and no observation/no dialogue. The two conditions that included observational practice were more effective (i.e., produced faster movement times) than the two conditions without it, both during practice and on a retention test performed under individual performance conditions. This suggests that the learning advantages of dyad practice are primarily due to the opportunity to observe another learner.     

Enhancing Motor Learning Through Dyad Practice

Abstract

It has been shown that practice in dyads, as compared to individual practice, can enhance motor learning and increase the efficiency of practice (as two participants can be trained at the same time; Shea, Wulf, &; Whitacre, 1999). The dyad practice protocol used by Shea et al. included both observation and dialogue between partners. Thus, it was not clear whether the learning benefits of dyad practice were due to observation, dialogue, or both. The present study examined the individual and interactive effects of observation and dialogue. The task used was speed cup stacking. Participants practiced under one of four conditions: observation/dialogue, observation/no dialogue, no observation/dialogue, and no observation/no dialogue. The two conditions that included observational practice were more effective (i.e., produced faster movement times) than the two conditions without it, both during practice and on a retention test performed under individual performance conditions. This suggests that the learning advantages of dyad practice are primarily due to the opportunity to observe another learner.     

Long-term effects of acoustic reafference training (ART)

In sport visual feedback is often used to enhance performance, mostly neglecting the auditory modality. However, athletes produce natural sounds when they move (acoustic reafferences) which they perceive and use to control their movements. We examined the short- and long-term effects of a training intervention on a complex movement by using acoustic reafferences. Natural step sounds produced during hurdling were recorded and played back to the participants immediately before each trial, with an increase (fast group), decrease (slow group), or no manipulation (control group) in the tempo. All groups increased their hurdling performance regarding overall running time, with the slow group showing the best performance development. After a 10-week retention, the fast and slow group further increased performance, whereas the control group declined. The repeated experience with acoustic information associated with the rhythmic pattern of hurdling may have helped developing a cognitive representation of that movement, especially regarding long-term effects.     

What determines limb selection for reaching?

While motor dominance appears to drive limb selection for reaching movements at the midline and ipsilateral (dominant) side, this study examined the possible determinants associated with what drives the programming of movements in response to stimuli presented in contralateral space. Experiment 1 distinguished between object proximity and a hemispheric bias for using the hand on the same side as the stimulus by comparing imagined and actual reaching with arms uncrossed and crossed. Experiment 2 examined the role of comfort in limb selection via participants reaching for a cube under two conditions: 1- and multiple-df movements. The first experiment demonstrated a proximity effect; participants preferred to keep their arms crossed to reach with the hand closest to the stimulus rather than uncrossing their arms to support a bias. Comfort was eliminated when participants continued to prefer the nondominant hand, even though they were able to reach with the dominant hand at all positions using only a 1-df movement. In summary, we offer evidence suggesting that limb selection in response to stimuli presented in contralateral hemispace is determined primarily by information related to the proximity between the stimulus and the hand.     

Systematically increasing contextual interference is beneficial for learning sport skills

Abstract

To better understand the contextual interference effect, in two experiments we investigated a form of practice schedule that provided novices with systematic increases in contextual interference. This new type of practice schedule was compared with traditional blocked and random scheduling for two types of sports skills. In Experiment 1, we tested the hypothesis that practising variations of the same task with systematic increases in contextual interference would lead to superior performance compared with blocked or random scheduling. Participants practised golf putting tasks following a blocked, random or increasing schedule, which involved initial blocked trials, followed by serial practice trials, and ended with random scheduling. Participants who followed the increasing schedule had superior retention test performance. In Experiment 2, we tested if these learning benefits were observed when learning tasks controlled by different generalized motor programs. Participants practised three different basketball passes (chest, overhead, single arm) in a blocked, random or increasing schedule. Participants practising with gradual increases in contextual interference performed better on retention and transfer tests than participants practising with blocked or random scheduling. The results of these two experiments indicate that a practice schedule offering systematic increases in contextual interference facilitates skill learning.     

Divided attention in bimanual aiming movements: effects on movement accuracy

The role of focusing attention on one limb or both limbs in a bimanual aiming task was investigated in two experiments. Participants were prompted to focus attention on either limb (Experiment 1) or were free to choose their attentional strategy (Experiment 2). Fifty-two college-aged participants made quick, bimanual lever reversals in the sagittal plane over 20 degrees and 60 degrees in 210 ms to the reversal point. In both experiments, spatial accuracy was better when participants focused their attention on a single limb compared to the nonattended limb and when they paid attention to both limbs. However, no differences were shown on a no-knowledge of results (KR) retention test when participants paid attention to both limbs. In the second experiment, differences were maintained on a no-KR retention test when participants continued to select their own attentional strategy, although the statistical effect was smaller than in the first experiment. The findings suggested that the movement parameter selection process benefited from attentional focus.     

Detecting and correcting errors in rapid aiming movements: effects of movement time, distance, and velocity

According to closed-loop accounts of motor control, movement errors are detected by comparing sensory feedback to an acquired reference state. Differences between the reference state and the movement-produced feedback results in an error signal that serves as a basis for a correction. The main question addressed in the current study was how distance, movement time, and velocity influence both spatial or temporal error detection. Forty college-aged participants (30 women and 10 men) performed rapid aiming movements over 30 degrees or 50 degrees in either 210 ms or 350 ms without vision. The participants verbally estimated the distance moved and the movement time during acquisition before knowledge of results was given and during an immediate retention test without knowledge of results. Spatial and temporal objective-subjective correlations were greater in the 210-ms condition compared to the 350-ms condition, but were not related to movement velocity.     

Effects of repeated retention tests on learning a single timing task

The purpose of the present study was to investigate the possibility that administering an initial retention test would influence any subsequent retention tests administered to the same participants. Participants performed 40 practice trials of a four-segment key-pressing task with a movement time goal of 925 ms. Participants were then administered either two retention tests (Day 1-Day 1 group, 10 min and 20 min after practice; Day 1-Day 2 group, 10 min and 24 hr after practice; Day 2-Day 2 group, 23 hr 50 min and 24 hr after practice) or one retention test (Day 1-Control group, 20 min after practice; Day 2-Control group, 24 hr after practice). The first test had a deleterious effect on performing the second test for the Day 2-Day 2 group, which would be expected if the task representation was updated and re-encoded at the time of recall using diminished information. This finding suggests that researchers should be cautious about using repeated retention tests that are administered 1 day after practice. In addition, teachers and coaches should consider administering a test under gamelike conditions following practice of a new technique. Otherwise, performance of the new technique may be degraded or perturbed at the time of later performances.     

Benefits of an external focus of attention: common coding or conscious processing?

We conducted two experiments to assess the effect attentional focus has on learning a complex motor skill and subsequent performance under secondary task loading. Participants in Experiment 1 learnt a golf putting task (300 practice trials) with a single instruction to either focus on their hands (internal focus) or the movement of the putter (external focus). No group differences were evident during learning or retention. Differences between the groups were only apparent under secondary task load; the external group's performance remained robust, while the internal group suffered a drop in performance. Verbal protocols demonstrated that the internal group accumulated significantly more internal knowledge and more task-relevant knowledge in general than the external group. Experiment 2 was designed to establish whether greater internal focus knowledge or greater explicit rule build up in general was responsible for performance breakdown. Two groups were presented with a set of six internal or external rules. Again, no performance differences were found during learning or retention. During the secondary task, both groups experienced performance deterioration. It was concluded that accumulation of explicit rules to guide performance was responsible for the internal group's breakdown in performance under secondary task loading and may be responsible for some of the performance differences reported previously.     

Distribution of practice and metacognition in learning and long-term retention of a discrete motor task

This study examined judgments of learning and the long-term retention of a discrete motor task (golf putting) as a function of practice distribution. The results indicated that participants in the distributed practice group performed more proficiently than those in the massed practice group during both acquisition and retention phases. No significant differences in retention performance were found as a function of three retention intervals (1, 7, and 28 days). Echoing actual acquisition scores, participants in the distributed practice group predicted more proficient retention performance than did those in the massed practice group. Although all participants predicted more proficient performance than was actually achieved, the difference between predicted and actual performance failed to reach significance.     

The Role of Interference and Task Similarity on the Acquisition,Retention, and Transfer of Simple Motor Skills

Abstract

The aim of the present study was to determine if two levels of task similarity influenced acquisition, retention, and transfer performance of three simple motor skills. Sixty right-handed subjects were randomly assigned to one of five (n = 12) experimental conditions. Each subject performed 72 trials during acquisition. Twenty-four trials were recorded for each movement task. Following a 5-min unfilled retention interval, subjects performed 4 trials on each task before completing 12 transfer trials of a novel movement. Contextual interference effects for acquisition and retention were supported for low but not high similarity tasks. Further, the results suggest that a different memory representation exists for high and low similarity tasks.     

The Effect of Knowledge of Results Delay and the Subjective Estimation of Movement Form on the Acquisition and Retention of a Motor Skill

Abstract

This study examined the effects of knowledge of results (KR) delay and subjective estimation of movement form on the acquisition and retention of a motor skill. During acquisition, four groups of participants performed 60 trials of a throwing accuracy task under the following conditions: (a) immediate KR, (b) delayed KR, (c) immediate KR + form estimation, and (d) delayed KR + form estimation. Retention tests of throwing accuracy and outcome error estimation in the absence of visual KR were administered 5 min and 24 hours following acquisition. Throwing accuracy was significantly higher during acquisition but significantly lower during retention for immediate-KR participants than for delayed-KR participants. However, participants who estimated their movement form during acquisition produced significantly higher throwing accuracy and lower estimation error during retention than those who did not.     

The effects of augmented kinematic feedback on motor skill learning in rifle shooting

In this study, we examined the effects of augmented kinematic knowledge of performance (KP) on shooting performance and learning. Knowledge of performance described the aiming trajectory of the rifle barrel. The effects of knowledge of performance were evaluated in terms of shooting accuracy (shooting score), variability of the shooting score (root mean square error) and rifle stability (x- and y-deviation of rifle movement). The participants (n = 40) were randomly assigned to one of four groups: no-KP, 50% KP, 100% KP and a control group. The three experimental groups performed 480 shots during a 4 week acquisition phase in which feedback was provided. No-feedback retention tests were administered at 2 and 10 days after acquisition. There were no differences between groups during acquisition. In the 2 day retention test, the mean shooting score of the group receiving 100% knowledge of performance was significantly higher than that of the other groups. Furthermore, variability in shooting score for the 100% KP group was lower than that for the 50% KP and control groups. No significant differences were found in rifle stability between the experimental groups. In summary, a high frequency of kinematic knowledge of performance improved shooting accuracy, but the effect appeared to be temporal, disappearing in the 10 day retention test. Given that a parallel effect was not found in rifle stability, future research should focus on examining the reasons for this improvement in shooting score.     

Composition of practice: influence on the retention of motor skills

The purpose of these experiments was to investigate further the variable practice effect found by Shea and Kohl (1990). Experiment 1 was an initial attempt to determine the locus of the retention benefits demonstrated by subjects provided variable practice experiences. All groups received 20 acquisition blocks consisting of five test trials per block at a target of 150 N. The interval between test trials was either unfilled or filled, with additional trials consisting of the same target force, variable target forces, or practice on an unrelated motor task. The results indicated retention was not incremented (relative to an unfilled interval) by requiring subjects to perform an unrelated motor task in the intertest-trial interval. However, when the interest-trial interval was filled with practice on related motor tasks, retention was significantly improved. Experiment 2 assessed the impact of increasing the number of related motor tasks interpolated between test trials. The results indicated filling the intertest-trial interval with one motor task resulted in large retention benefits relative to an unfilled interval. Further increases in the number of related motor tasks (3) interpolated between test trials resulted in only modest increments to retention. The results were consistent with the elaboration perspective proposed by Shea and Zimny (1983). The elaboration perspective proposes that the simultaneous presence of related items in working memory facilitates interitem elaborative and distinctive processing that ultimately results in retention benefits.     

Forthcoming events

Abstract

We conducted two experiments to assess the effect attentional focus has on learning a complex motor skill and subsequent performance under secondary task loading. Participants in Experiment 1 learnt a golf putting task (300 practice trials) with a single instruction to either focus on their hands (internal focus) or the movement of the putter (external focus). No group differences were evident during learning or retention. Differences between the groups were only apparent under secondary task load; the external group's performance remained robust, while the internal group suffered a drop in performance. Verbal protocols demonstrated that the internal group accumulated significantly more internal knowledge and more task-relevant knowledge in general than the external group. Experiment 2 was designed to establish whether greater internal focus knowledge or greater explicit rule build up in general was responsible for performance breakdown. Two groups were presented with a set of six internal or external rules. Again, no performance differences were found during learning or retention. During the secondary task, both groups experienced performance deterioration. It was concluded that accumulation of explicit rules to guide performance was responsible for the internal group's breakdown in performance under secondary task loading and may be responsible for some of the performance differences reported previously.     

Composition of Practice: Influence on the Retention of Motor Skills

Abstract

The purpose of these experiments was to investigate further the variable practice effect found by Shea and Kohl (1990). Experiment 1 was an initial attempt to determine the locus of the retention benefits demonstrated by subjects provided variable practice experiences. All groups received 20 acquisition blocks consisting of five test trials per block at a target of 150 N. The interval between test trials was either unfilled or filled, with additional trials consisting of the same target force, variable target forces, or practice on an unrelated motor task. The results indicated retention was not incremented (relative to an unfilled interval) by requiring subjects to perform an unrelated motor task in the intertest–trial interval. However, when the intertest–trial interval was filled with practice on related motor tasks, retention was significantly improved. Experiment 2 assessed the impact of increasing the number of related motor tasks interpolated between test trials. The results indicated filling the intertest–trial interval with one motor task resulted in large retention benefits relative to an unfilled interval. Further increases in the number of related motor tasks (3) interpolated between test trials resulted in only modest increments to retention. The results were consistent with the elaboration perspective proposed by Shea and Zimny (1983). The elaboration perspective proposes that the simultaneous presence of related items in working memory facilitates interitem elaborative and distinctive processing that ultimately results in retention benefits.