Modeling parallelization and flexibility improvements in skill acquisition: from dual tasks to complex dynamic skills

Emerging parallel processing and increased flexibility during the acquisition of cognitive skills form a combination that is hard to reconcile with rule-based models that often produce brittle behavior. Rule-based models can exhibit these properties by adhering to 2 principles: that the model gradually learns task-specific rules from instructions and experience, and that bottom-up processing is used whenever possible. In a model of learning perfect time-sharing in dual tasks (Schumacher et al., 2001), speedup learning and bottom-up activation of instructions can explain parallel behavior. In a model of a complex dynamic task (Carnegie Mellon University Aegis Simulation Program [CMU-ASP], Anderson et al., 2004), parallel behavior is explained by the transition from serially organized instructions to rules that are activated by both top-down (goal-driven) and bottom-up (perceptually driven) factors. Parallelism lets the model opportunistically reorder instructions, leading to the gradual emergence of new task strategies.     

Determinants of Children's Primary Health Care Use

We review factors that influence children's use of primary health care services. Predictors of pediatric health care use include child health status, child mental health, parent and family functioning, demographic characteristics, and access to health care services. Health services research is marked by inconsistencies due to varying approaches to measurement, population sampling, and analysis, and models that do not incorporate situational factors. We present recommendations for practicing clinicians and discuss suggestions for future research to help identify additional factors that may influence a parent's decision to seek help from pediatric physicians. Health care use is determined by multiple factors, and complex models will lead to improved strategies for maximizing health status and establishing optimal pediatric care.     

Motor sequence learning in children with recovered and persistent developmental stuttering: preliminary findings

PurposePrevious studies have associated developmental stuttering with difficulty learning new motor skills. We investigated non-speech motor sequence learning in children with persistent developmental stuttering (CWS), children who have recovered from developmental stuttering (CRS) and typically developing controls (CON).MethodsOver the course of two days, participants completed the Multi-Finger Sequencing Task, consisting of repeated trials of a10-element sequence, interspersed with trials of random sequences of the same length. We evaluated motor sequence learning using accuracy and response synchrony, a timing measure for evaluation of sequencing timing. We examined error types as well as recognition and recall of the repeated sequences.ResultsCWS demonstrated lower performance accuracy than CON and CRS on the first day of the finger tapping experiment but improved to the performance level of CON and CRS on the second day. Response synchrony showed no overall difference among CWS, CRS and CON.Learning scores of repeated sequences did not differ from learning scores of random sequences in CWS, CRS and CON. CON and CRS demonstrated an adaptive strategy to response errors, whereas CWS maintained a high percentage of corrected errors for both days.ConclusionsOur study examined non-speech sequence learning across CWS, CRS and CON. Our preliminary findings support the idea that developmental stuttering is not associated with sequence learning per se but rather with general fine motor performance difficulties.     

不良生活经历对大学生冷酷无情特质的影响：有调节的中介效应

为考察不良生活经历对大学生冷酷无情特质的影响机制,采用问卷法调查了湖南省4所学校1872名大学生。结果发现：（1）心理弹性在不良生活经历与大学生冷酷无情特质之间具有部分中介效应,不良生活经历既对冷酷无情特质产生直接影响,也能通过心理弹性对冷酷无情特质产生间接影响;（2）社会支持利用度对心理弹性的中介作用具有调节效应,它调节了中介过程的前半路径和后半路径。因此,不良生活经历对大学生冷酷无情特质的影响具有调节的中介效应。     

The Ecology of Adolescent Substance Abuse Service Utilization

This paper presents an ecological-community model toward the explanation of variation in patterns of substance abuse (SA) service utilization among adolescents who are enrolled in Tennessee's Medicaid program (TennCare). Guided by a theoretical framework that draws from the social ecology work of Bronfenbrenner and health services utilization models promoted by Aday and Andersen, we apply a social indicators approach toward explaining the impact of community ecology on identification of SA and treatment engagement. Both county-level rates and individual-level treatment utilization are examined and hierarchical linear modeling is incorporated to examine the individual-in-community phenomenon. This study is an expansion of previous service utilization research and suggests that explanations of youth's service utilization must necessarily include not only individual, familial, and service system characteristics, but community factors, as well.     

Effects of different swimming race constraints on turning movements

The aim of this study was to investigate the effects of different swimming race constraints on the evolution of turn parameters. One hundred and fifty-eight national and regional level 200-m (meters) male swimming performances were video-analyzed using the individualized-distance model in the Open Comunidad de Madrid tournament. Turn (p < .001, ES = 0.36) and underwater distances (p < .001, ES = 0.38) as well as turn velocity (p < .001, ES = 0.69) significantly dropped throughout the race, although stroke velocity and underwater velocity were maintained in the last lap of the race (p > .05). Higher expertise swimmers obtained faster average velocities and longer distances in all the turn phases (p < .001, ES = 0.59), except the approach distance. In addition, national level swimmers showed the ability to maintain most of the turn parameters throughout the race, which assisted them in improving average velocity at the end of races. Therefore, the variations in the turning movements of a swimming race were expertise-related and focused on optimizing average velocity. Turning skills should be included in the swimming race action plan.     

Task-specificity of balance training

Despite much research on balance training, it is still unclear whether balance training leads to highly task-specific adaptations or rather non-specific adaptations. Hence, in this study we examined whether balance training increased performance only in the balance task that was trained or also in non-trained tasks. Forty healthy participants (28 m 12 f, 25 ± 4 years, 177 ± 10 cm, 73 ± 14 kg) were assigned to one of two training groups (TGs) or a control group. Both TGs completed six sessions over 2 weeks, only the training device differed. Before and after the training, performance in the trained task as well as in additional untrained tasks was recorded. ANOVAs showed that each TG outperformed the other groups only in the task they had trained (e.g., task trained by TG1: +225% in TG1, only +41% and +30% in TG2 and control, group * time interaction, p < 0.001; Untrained task 1: TG1 +48%, TG2 +48%, and control +30%, no significant interaction, p = 0.72). In summary, 2 weeks of balance training resulted in highly task-specific effects, no transfer even to very similar tasks was observed. Therefore, we recommend identifying and training exactly those tasks that need improvement, and test the efficacy of training programs using specific tests instead of general tests with limited functional relevance.     

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.     

Judgments of learning are significantly higher following feedback on relatively good versus relatively poor trials despite no actual learning differences

Studies have consistently shown that prospective metacognitive judgments of learning are often inaccurate because humans mistakenly interpret current performance levels as valid indices of learning. These metacognitive discrepancies are strongly related to conditions of practice. Here, we examined how the type of feedback (after good versus poor trials) received during practice and awareness (aware versus unaware) of this manipulation affected judgments of learning and actual learning. After each six-trial block, participants received feedback on their three best trials or three worst trials and half of the participants were made explicitly aware of the type of feedback they received while the other half were unaware. Judgments of learning were made at the end of each six-trial block and before the 24-h retention test. Results indicated no motor performance differences between groups in practice or retention; however, receiving feedback on relatively good compared to relatively poor trials resulted in significantly higher judgments of learning in practice and retention, irrespective of awareness. These results suggest that KR on relatively good versus relatively poor trials can have dissociable effects on judgments of learning in the absence of actual learning differences, even when participants are made aware of their feedback manipulation.     

Expecting to teach enhances motor learning and information processing during practice

Recent research has revealed that having learners study and practice a motor skill with the expectation of having to teach it enhances motor learning. However, the mechanisms underlying this effect remain unknown. We attempted to replicate this effect and elucidate the mechanisms underlying it. Thus, participants studied golf putting instructions and practiced putting either with the expectation of having to teach another participant how to putt or the expectation of being tested on their putting. During this acquisition phase, participants’ motivation, anxiety, and information processing (the duration they took preparing each putt) were indexed as possible mechanisms underlying a motor learning effect. One day and seven days after the acquisition phase, learning was assessed by testing all participants on their golf putting. Results revealed that expecting to teach enhanced motor learning, replicating the original finding. Moreover, expecting to teach increased the duration participants took preparing each putt, which was correlated with superior motor learning. Thus, results suggest expecting to teach enhances motor learning by increasing information processing during practice.