Examining changes in corticospinal excitability and balance performance in response to social-comparative feedback.

BACKGROUND: Social-comparative feedback informs an individual that their performance was better or worse than the group. Previous studies have found that compared to knowledge of results alone, social-comparative feedback produces a valence response that results in larger improvements in balance performance. However, the neural processes contributing to these motor improvements have not yet been examined. RESEARCH QUESTION: Does social-comparative feedback alter corticospinal excitability and consequently, balance performance? METHODS: Thirty-six healthy young adults stood and maintained their balance on a stabiliometer for eight trials. After three of the trials, the neutral (i.e., only knowledge of results) group received their performance feedback (i.e., time on balance) while the other two groups also received positive (i.e., performed better than the group) or negative (i.e., performed worse than the group) social-comparative feedback. To measure corticospinal excitability, soleus motor-evoked potentials were elicited using transcranial magnetic stimulation at the beginning of the experiment, after the presentation of feedback, and at the end of the experiment. Pre- and post- ratings of confidence, perceived skill, motivation, and anxiety were also collected. RESULTS: The negative feedback group reported decreases in perceived skill (43 ± 29%) and balance confidence (26 ± 28%), while the positive group reported a 13 ± 17% increase in perceived skill. Despite these group differences in feedback perception, all three groups improved their balance performance by ≈35% (p < 0.001) by the eighth trial. However, this improvement in balance performance was not matched by any changes in corticospinal excitability over time (19.2 ± 55.9% change; p = 0.340) or between groups (p = 0.734). SIGNIFICANCE: Our findings suggest that social-comparative feedback, as presented in this study, does not affect corticospinal excitability and balance performance differently than knowledge of results (neutral feedback) alone. More arousing and more frequent forms of social-comparative feedback may be necessary for observing larger changes in the functional or neural control of balance.

Measuring Investment in Learning: Can Electrocardiogram Provide an Indication of Cognitive Effort During Learning?

Heart rate variability (i.e., low frequency:high frequency ratio) was measured to differentiate invested cognitive effort during the acquisition and retention of a novel task. Participants (12 male, M = 25.1 year, SD = 3.6; 12 female, M = 22.8 year, SD = 1.1) were required to produce Braille equivalents of English letter primes on a standardized keyboard in proactive or retroactive conditions (groups, each n = 12). The correct Braille response was either provided before (i.e., proactively) or after (i.e., retroactively) the participant's response. During acquisition, participants in the proactive group demonstrated shorter study time, greater recall success, and reported lower cognitive investment. Participants in the proactive and retroactive groups did not statistically differ in heart rate variability. For retention, the retroactive group showed greater recall success, lower perceived cognitive effort investment, and lower heart rate variability. The results highlight the usefulness of heart rate variability in discriminating the cognitive effort invested for a recently acquired skill.

Accuracy of Subjective Performance Appraisal is Not Modulated by the Method Used by the Learner During Motor Skill Acquisition.

The present experiment examined whether the method of subjectively appraising motor performance during skill acquisition would differentially strengthen performance appraisal capabilities and subsequent motor learning. Thirty-six participants (18 men and 18 women; M age = 20.8 years, SD = 1.0) learned to execute a serial key-pressing task at a particular overall movement time (2550 ms). Participants were randomly separated into three groups: the Generate group estimated their overall movement time then received knowledge of results of their actual movement time; the Choice group selected their perceived movement time from a list of three alternatives; the third group, the Control group, did not self-report their perceived movement time and received knowledge of results of their actual movement time on every trial. All groups practiced 90 acquisition trials and 30 no knowledge of results trials in a delayed retention test. Results from the delayed retention test showed that both methods of performance appraisal (Generate and Choice) facilitated superior motor performance and greater accuracy in assessing their actual motor performance compared with the control condition. Therefore, the processing required for accurate appraisal of performance was strengthened, independent of performance appraisal method.

The influence of instruction on arm reactions in individuals with Parkinson's disease.

The purpose of this study was to examine whether explicit instruction would facilitate arm reactions in individuals with Parkinson's disease (PD). Individuals with (n = 10) and without (n = 15) PD responded to unexpected support-surface translations. To recover their balance, participants were required to either respond naturally (react natural) or to reach toward a nearby handrail (explicit instruction). Arm reactions were quantified from electromyographic (EMG) and arm kinematic recordings. Results showed that while explicit instruction led to earlier and larger arm reactions, the benefits were not different between individuals with and without PD. Specifically, when explicitly instructed to reach toward a handrail, shoulder EMG responses were 4% earlier (p = .005) and 32% larger (p < .001) compared to when instructed to react naturally. A 44% greater peak wrist medio-lateral velocity (p < .001) and a 29% greater peak shoulder abduction angular velocity (p < .001) were also observed when participants were instructed to direct their arms toward a handrail after an unexpected support-surface translation. Explicit instruction also led to a higher frequency of handrail contact and a 49 ms earlier time to handrail contact compared to the react natural condition (p = .015). These results suggest that providing instruction to promote arm movement may help reduce falls in older adults with and without PD.

Learning effects of self-controlled practice scheduling for children and adults: are the advantages different?

The benefit of providing learners control over their repetition schedule during multi-task learning has been limited to adult samples. Recently, differences in self-controlled strategies, such as frequent requests for knowledge of results by children (10 years) compared to adults have been reported. The purpose of the present experiment was to assess the benefits of a self-controlled repetition schedule during multi-task learning for children compared to adults. Twenty-four children (M age = 11.7 yr., SD = 2.0) and 24 adults (M age = 22.0 yr., SD = 2.2) completed 36 acquisition (12 per sequence) and 12 retention trials (4 per sequence) over two days for a key-pressing task. Half the adults (n = 12) and half the children (n = 12) chose the order in which to practice the three sequences during acquisition. The remaining participants practiced under the repetition schedule of a self-controlled counterpart. The dependent variables were the total time to complete the trial and the success of the motor trial (successful or unsuccessful). No differences were observed in the total number of times participants switched from one sequence to another in acquisition for the children and adults in the self-controlled condition. In retention, the proportion of error trials did not differ between the children and adults. The main effect for self-controlled vs yoked conditions indicated superior learning for the self-controlled conditions independent of age.

Self-controlled KR schedules: does repetition order matter?

The impact of an experimenter-defined repetition schedule on the utility of a self-controlled KR context during motor skill acquisition was examined. Participants were required to learn three novel spatial-temporal tasks in either a random or blocked repetition schedule with or without the opportunity to control their KR. Results from the retention period showed that participants provided control over their KR schedule in a random repetition schedule demonstrated superior learning. However, performance measures from the transfer test showed that, independent of repetition schedule, learners provided the opportunity to control their KR schedule demonstrated superior transfer performance compared to their yoked counterparts. The dissociated impact of repetition schedule and self-controlled KR schedules on retention and transfer is discussed.

Self-controlled knowledge of results: age-related differences in motor learning, strategies, and error detection.

Research has demonstrated that a self-controlled KR schedule is advantageous for motor learning; however, the usefulness of a self-controlled KR context in older adults remains unknown. To address this gap in knowledge, we examined whether (1) the learning benefits of a self-controlled KR schedule are modulated by the age of the learner; (2) practicing in a self-controlled KR context concurrently strengthens the learner's error detection mechanism, and (3) the KR strategy during acquisition changes as a function of practice trials completed and age. As a function of age, participants were quasirandomly assigned to either the self-control or yoked group resulting in four experimental groups (Self-Young, Yoked-Young, Self-Old, and Yoked-Old). The results revealed the Self-Young group: (1) demonstrated superior retention performance than all other groups (p<.05); (2) was more accurate in estimating motor performance than all other groups during retention (p<.05), and (3) self-reported a switch in their strategy for requesting KR during acquisition based on the number of practice trials completed. Collectively, our findings suggest that older adults do not demonstrate the same learning benefits of a self-controlled KR context as younger adults which may be attributed to differences in KR strategies.

Knowing the good from the bad: does being aware of KR content matter?

Previous researchers have suggested that providing KR based on only successful (i.e., good trials) trials enhances learning compared to providing KR on unsuccessful trials (i.e., poor trials). However, the learners were unaware the content of their KR display was based entirely on their successful or unsuccessful trials. Thus, the purpose of the present experiment was to determine whether learning after providing KR after relatively good trials would persist if participants were aware of their KR content. All participants propelled a slider with their non-dominant hand to a pre-determined distance on a linear slide. Participant's vision was occluded before, during and after their motor action. Similar to previous research, all participants were provided KR on three trials in a series of 6 trial blocks regarding their three best (KR good) or three worst (KR poor) trials in the block, and were either aware (good-aware; poor-aware) or unaware (good-unaware, poor-unaware) of content in their KR display. The retention results showed the groups aware of their KR content demonstrated superior learning to the groups unaware of their KR content. These findings suggest that in addition to the motivational components of KR, awareness of the KR content directly impacted motor skill acquisition not whether KR was presented on good trials or poor trials.

Understanding Self-Controlled Motor Learning Protocols through the Self-Determination Theory.

The purpose of the present review was to provide a theoretical understanding of the learning advantages underlying a self-controlled practice context through the tenets of the self-determination theory (SDT). Three micro-theories within the macro-theory of SDT (Basic psychological needs theory, Cognitive Evaluation Theory, and Organismic Integration Theory) are used as a framework for examining the current self-controlled motor learning literature. A review of 26 peer-reviewed, empirical studies from the motor learning and medical training literature revealed an important limitation of the self-controlled research in motor learning: that the effects of motivation have been assumed rather than quantified. The SDT offers a basis from which to include measurements of motivation into explanations of changes in behavior. This review suggests that a self-controlled practice context can facilitate such factors as feelings of autonomy and competence of the learner, thereby supporting the psychological needs of the learner, leading to long term changes to behavior. Possible tools for the measurement of motivation and regulation in future studies are discussed. The SDT not only allows for a theoretical reinterpretation of the extant motor learning research supporting self-control as a learning variable, but also can help to better understand and measure the changes occurring between the practice environment and the observed behavioral outcomes.

Decreasing the proportion of self-control trials during the acquisition period does not compromise the learning advantages in a self-controlled context.

The present experiment examined the learning effects of participants self-controlling their receipt of knowledge of results (KR) on all or half of their acquisition trials (50%). For participants who were provided 50% self-control, the first half of their acquisition period consisted of receiving KR on all trials, or according to a faded-KR schedule. Participants practiced a sequential timing task. The results showed that independent of practice condition, participants who self-controlled their KR during the acquisition period demonstrated superior performance compared to the respective yoked conditions in the retention and transfer portion of the experiment. These results extend previous research by suggesting that decreasing the proportion of self-control trials does not compromise learning in a self-controlled context.

Self-regulated frequency of augmented information in skill learning.

The authors examined the effects of self-regulating task information, identical in content, either before (proactive) or after (retroactive) a motor action. Participants were required to learn unique typographical script used to enter data into a personal data assistant. Consistent with previous findings, presenting task information proactively during acquisition facilitated performance, but presenting task information retroactively resulted in superior learning as measured in retention tests. However, those who self-regulated proactive task information demonstrated learning that was equivalent to those who received retroactive task information. These results suggest that when task information is equated, the learning benefits associated with self-regulation are independent of the timing of when the augmented information is made available during practise.

Learner regulated knowledge of results during the acquisition of multiple timing goals.

The purpose of the present experiment was to examine the advantages of a learner controlled KR schedule during the acquisition of three novel sequential timing tasks. The self-regulated group requested KR when necessary during the acquisition period while participants in the yoked condition replicated the KR schedule of a self-regulated counterpart, without the choice. The self-regulated condition demonstrated superior performance in retention and transfer, with a relative KR frequency similar for all three sequences. Similar to Chiviacowsky and Wulf (2002), learners also demonstrated a preference for KR after perceived good trials, independent of defined task difficulty. Thus, the results extend previous research by suggesting a generalized learning strategy by performers acquiring multiple motor task goals.

Examining the proactive and retroactive placement of augmented information for learning a novel computer alphabet.

The timing of augmented information, either prior to or following a memory retrieval attempt has profound, and opposing, influences on immediate performance and retention. This effect was investigated in 2 experiments in which participants learned typographical symbols used to enter information into a personal data assistant. The effects of the spacing of the second of 2 repetitions (Experiment 1) and the number of retrieval attempts during practice (Experiment 2) failed to modify the relative effectiveness of the timing of augmented information--proactive information (prior to retrieval attempt) facilitated practice but degraded retention relative to retroactive information (after retrieval attempt). The theoretical roles of the timing of augmented information relative to the functions of retrieval practice were discussed.

Learning a new human-computer alphabet: the role of similarity and practice.

Two purposes motivated this study: (a) to quantify the difficulty in learning various symbols of the alphabet used to enter data into a personal digital assistant (PDA), and (b) to investigate the interaction of item difficulty with practice conditions that promote varying levels of cognitive effort. Levels of compatibility between members of the PDA alphabet and English were quantified through introspective ratings in Experiment 1 and objective performance measures in Experiment 2. Three levels of item compatibility were learned under conditions of proactive or retroactive augmented information in Experiment 3. Contrary to expectations, the item similarity effect did not interact with practice schedules--a retroactive augmented information condition resulted in degraded levels of acquisition performance, but superior retention levels, compared to the proactive condition. These findings are discussed in terms of the relative merits of cognitive effort in skill acquisition.