Deliberate Control of Continuous Motor Performance

The authors examined the means by which people vary movement parameters to satisfy more than 1 constraint at a time in a repetitive motor task. The authors expected that when participants (N = 12) were simultaneously confronted with spatial and temporal constraints in an ellipse-drawing task, they would either exploit the intrinsic amplitude-frequency relationships or activate less natural control regimes to prioritize their movement goals. By focusing on local amplitude and frequency errors and parameter changes from 1 movement to the next, the authors distinguished parameter changes that reflected exploitation of biomechanics from those that required deliberate control. The findings demonstrated that at low movement speeds, participants can pursue multiple movement goals simultaneously; at higher speeds, their capacity to satisfy multiple task goals is reduced. The authors used a new method of inferring deliberate control from movement kinematics in the present study.     

Deliberate control of continuous motor performance

The authors examined the means by which people vary movement parameters to satisfy more than 1 constraint at a time in a repetitive motor task. The authors expected that when participants (N = 12) were simultaneously confronted with spatial and temporal constraints in an ellipse-drawing task, they would either exploit the intrinsic amplitude-frequency relationships or activate less natural control regimes to prioritize their movement goals. By focusing on local amplitude and frequency errors and parameter changes from 1 movement to the next, the authors distinguished parameter changes that reflected exploitation of biomechanics from those that required deliberate control. The findings demonstrated that at low movement speeds, participants can pursue multiple movement goals simultaneously; at higher speeds, their capacity to satisfy multiple task goals is reduced. The authors used a new method of inferring deliberate control from movement kinematics in the present study.     

Control of velocity and position in single joint movements

Previous research on single joint movements has lead to the development of models of control that propose that movement speed and distance are controlled through an initial pulsatile signal that can be modified in both amplitude and duration. However, the manner in which the amplitude and duration are modulated during the control of movement remains controversial. We now report two studies that were designed to differentiate the mechanisms used to control movement speed from those employed to control final position accuracy. In our first study, participants move at a series of speeds to a single spatial target. In this task, acceleration duration (pulse-width) varied substantially across speeds, and was negatively correlated with peak acceleration (pulse-height). In a second experiment, we removed the spatial target, but required movements at the three speeds similar to those used in the first study. In this task, acceleration amplitude varied extensively across the speed targets, while acceleration duration remained constant. Taken together, our current findings demonstrate that pulse-width measures can be modulated independently from pulse-height measures, and that a positive correlation between such measures is not obligatory, even when sampled across a range of movement speeds. In addition, our findings suggest that pulse-height modulation plays a primary role in controlling movement speed and specifying target distance, whereas pulse-width mechanisms are employed to correct errors in pulse-height control, as required to achieve spatial precision in final limb position.     

Children’s coding of human action: cognitive factors influencing imitaation in 3‐year‐old

We used imitation as a tool for investigating how young children code action. The study was designed to examine the errors children make in re‐enacting manual gestures they see. Thirty‐two 3‐year‐old children served as subjects. Each child was shown 24 gestures, generated by systematically crossing four factors: visual monitoring, spatial endpoint, movement path, and number of hands. The results showed no difference as a function of whether the children could visually monitor their own responses. Interestingly, children made significantly more errors when the adult's action terminated on a body part than they did when the same movement terminated near the body part. There were also significantly more errors when the demonstrated act involved crossing midline than when it did not, and more errors when it involved one hand rather than two hands. Our hypothesis is that human acts are coded in terms of goals. The goals are hierarchically organized, and because young children have difficulty simultaneously integrating multiple goals into one act they often re‐enact the goals that are ranked higher, which leads to the errors observed. We argue that imitation is an active reconstruction of perceived events and taps cognitive processing. We suggest that the goal‐based imitation in 3‐year‐olds is a natural developmental outgrowth of the perceptual–motor mapping and goal‐directed coding of human acts found in infancy.     

Parameterization of movement execution in children with developmental coordination disorder

The Rhythmic Movement Test (RMT) evaluates temporal and amplitude parameterization and fluency of movement execution in a series of rhythmic arm movements under different sensory conditions. The RMT was used in combination with a jumping and a drawing task, to evaluate 36 children with Developmental Coordination Disorder (DCD) and a matched control group. RMT errors in space and in time were significantly larger for children with DCD. Omission of sensory information decreased the accuracy of movement parameterization in children with DCD more than in the control group, suggesting that children with DCD have more problems in building up an internal representation of the movement. Errors in time correlated significantly with the jumping and drawing task, while errors in space did not. Deficits of temporal movement parameterization might be one of the underlying causes of poor motor performance in some children with DCD.     

The effect of amplitude and accuracy requirements on movement time in children

The object of this study was to investigate how children control their movements, through- the analysis of Fitts' Law on subjects 5, 7, 9, and 11 yr of age. Children had to perform rapid alternative pointing movements between two targets, varying in width and distance (level of difficulty of the task). The analysis of movement time showed that, as children grow up, movement speed increased and was gradually less affected by the level of difficulty of a given task; moreover the respective effects of accuracy and amplitude requirements on movement time changed with age, resulting in distinct evolutive patterns. The results are thereby discussed in relation to the respective development of both programming and guiding components of movement in children. A few observations about ocular strategies during the task were also noted.     

Movement Control Strategies in a Dynamic Balance Task in Children With and Without Developmental Coordination Disorder

Abstract

Our study aimed to analyze movement control strategies using predefined criteria for amplitude and differences in these strategies between children with and without DCD. Children with (n?=?28) and without DCD (n?=?15) were included. A video-observation-tool was used to score the moving body parts during a Wii Fit slalom task over multiple time points. Two-step cluster analysis was used to extract distinct movement strategies. Two different movement strategies were identified that were independently validated by a measure of task performance and a subjective mark of quality of the movement. Initial differences between groups and changes over time toward the more successful strategy were found in both groups, albeit in a different percentage. This study shows that the more efficient movement strategy is seen in the majority of the TD children and only in a small number of children with DCD, even after practice.     

小学生系列回忆中移动和重复错误特征的研究

以小学一、三、五年级学生为被试,以同音汉字为实验材料,要求被试完成系列回忆任务。实验发现：移动错误随年级的增高而减少,年级差异显著;移动错误出现最多的是在移动距离为1个和2个的时候,移动距离差异显著;重复错误年级差异和移动距离差异均不明显。     

Individual differences in motor development during early childhood: An MEG study

In a previous study, we reported the first measurements of pre‐movement and sensorimotor cortex activity in preschool age children (ages 3–5 years) using a customized pediatric magnetoencephalographic system. Movement‐related activity in the sensorimotor cortex differed from that typically observed in adults, suggesting that maturation of cortical motor networks was still incomplete by late preschool age. Here we compare these earlier results to a group of school age children (ages 6–8 years) including seven children from the original study measured again two years later, and a group of adults (mean age 31.1 years) performing the same task. Differences in movement‐related brain activity were observed both longitudinally within children in which repeated measurements were made, and cross‐sectionally between preschool age children, school age children, and adults. Movement‐related mu (8–12 Hz) and beta (15–30 Hz) oscillations demonstrated linear increases in amplitude and mean frequency with age. In contrast, movement‐evoked gamma synchronization demonstrated a step‐like transition from low (30–50 Hz) to high (70–90 Hz) narrow‐band oscillations, and this occurred at different ages in different children. Notably, pre‐movement activity (‘readiness fields’) observed in adults was absent in even the oldest children. These are the first direct observations of brain activity accompanying motor responses throughout early childhood, confirming that maturation of this activity is still incomplete by mid‐childhood. In addition, individual children demonstrated markedly different developmental trajectories in movement‐related brain activity, suggesting that individual differences need to be taken into account when studying motor development across age groups.     

Fine motor deficiencies in children with developmental coordination disorder and learning disabilities: an underlying open-loop control deficit

Thirty-two children with Developmental Coordination Disorder (DCD) and learning disabilities (LD) and their age-matched controls attending normal primary schools were investigated using kinematic movement analysis of fine-motor performance. Three hypotheses about the nature of the motor deficits observed in children with LD were tested: general slowness hypothesis, limited information capacity hypothesis, and the motor control mode hypothesis. Measures of drawing movements were analyzed under different task conditions using a Fitts' paradigm. In a reciprocal aiming task, the children drew straight-line segments between two targets 2.5 cm apart. Three Target Sizes were used (0.22, 0.44, and 0.88 cm). Children used an electronic pen that left no trace on the writing tablet. To manipulate the degree of open-loop movement control, the aiming task was performed under two different control regimes: discrete aiming and cyclic aiming. The kinematic analysis of the writing movements of the 32 children with DCD/LD that took part in the experimental study confirmed that besides learning disabilities they have a motor learning problem as well. Overall, the two groups did not differ in response time, nor did they respond differently according to Fitts' Law. Both groups displayed a conventional trade-off between Target Size and average Movement Time. However, while movement errors for children with DCD/LD were minimal on the discrete task, they made significantly more errors on the cyclic task. This, together with faster endpoint velocities, suggests a reduced ability to use a control strategy that emphasizes the terminal control of accuracy. Taken together, the results suggest that children with DCD/LD rely more on feedback during movement execution and have difficulty switching to a feedforward or open-loop strategy.     

An extended motor network generates beta and gamma oscillatory perturbations during development

This study examines the time course and neural generators of oscillatory beta and gamma motor responses in typically-developing children. Participants completed a unilateral flexion–extension task using each index finger as whole-head magnetoencephalography (MEG) data were acquired. These MEG data were imaged in the frequency-domain using spatial filtering and the resulting event-related synchronizations and desynchronizations (ERS/ERD) were subjected to voxel-wise statistical analyses to illuminate time–frequency specific activation patterns. Consistent with adult data, these children exhibited a pre-movement ERD that was strongest over the contralateral post-central gyrus, and a post-movement ERS response with the most prominent peak being in the contralateral precentral gyrus near premotor cortices. We also observed a high-frequency (∼80 Hz) ERS response that coincided with movement onset and was centered on the contralateral precentral gyrus, slightly superior and posterior to the beta ERS. In addition to pre- and post-central gyri activations, these children exhibited beta and gamma activity in supplementary motor areas (SMA) before and during movement, and beta activation in cerebellar cortices before and after movement. We believe the gamma synchronization may be an excellent candidate signal of basic cortical motor control, as the spatiotemporal dynamics indicate the primary motor cortex generates this response (and not the beta oscillations) which is closely yoked to the initial muscle activation. Lastly, these data suggest several additional neural regions including the SMA and cerebellum are involved in basic movements during development.     

Role of proprioceptive information in movement programming and control in 5 to 11-year old children

The role of proprioceptive inputs in the control of goal-directed movements was examined, by means of the tendon vibration technique, in 5 to 11-year old children performing a serial pointing task. Children pointed, with movements of various amplitudes and at various positions, by alternating wrist flexions and extensions. Tendon vibration was applied to both agonist and antagonist muscles to perturb relevant muscular proprioceptive inputs during the static or dynamic phase of the task, i.e., during stops on targets or during movement execution. Constant and variable amplitude errors as well as constant position error were evaluated. Vibratory perturbation applied during movement execution resulted in a similar reduction in movement amplitude, yielding an increased constant error in all age groups and a systematic position error in the direction of the movement starting point. Perturbing proprioception during static phases preceding movement resulted in an age-related increase in the variable amplitude error, which was maximal in 5-year old children performing extension movements. The results were interpreted in terms of the use of proprioceptive information in the feedforward and feedback based components of movement control in children. In particular, the results indicated (1) developmental changes in the relative weighting of each component, (2) an increased capacity to move from one strategy to the other, depending on the availability of information, and (3) developmental changes from an alternated to an integrated control of amplitude and position in serial pointing.     

Voluntary control of pelvic frontal rotations in belly dance experts

The present study investigated how belly dance experts perform the “hip shimmy”, a complex rhythmic dance movement consisting in a voluntary oscillation of the pelvis exclusively in the frontal plane with maximised amplitude, with no movement of the upper trunk. The aims of this study were to 1) assess whether the amplitude and stability of the pelvic movement can be maximised in certain postural and frequency conditions; and 2) investigate in a 1 to 3 Hz range whether it is indeed possible to oscillate the pelvis only in the frontal plane and to dissociate this one-axis pelvic rotation from potential spontaneous upper-trunk oscillations. Nineteen belly dance experts performed this task in three frequencies and three knee bending postures. Eight joint angles were calculated using the kinematic data of 20 markers over the entire body collected with a motion capture system. Mean amplitude, frequency, and spatial and temporal variability of frontal pelvic oscillations were analysed to characterise motor performance and movement stability. Five Continuous Relative Phases (CRP) were computed to identify the modes and stability of coordination patterns. The results showed that a low posture enhances amplitude performance and that the pelvic oscillation amplitude tended to decrease at 3 Hz, although between-condition differences remained small. Temporal stability was highest at 2 Hz and significant inter-individual differences emerged at 3 Hz. CRP analysis revealed an unpreventable coupling between pelvis and upper-trunk oscillations in the frontal and transversal planes. A consistent antiphase coordination between transversal pelvis and upper-trunk may have been caused by anatomical and counter-balancing constraints. In the frontal plane, multiple stable pelvis-upper trunk patterns including inphase, out-of-phase and antiphase evolved to antiphase predominance and inphase disappearance upon reaching 3 Hz. In sum, increasing frequency highlighted the concomitance of two control phenomena: the inter-individual differentiation in performance and standardisation of the possible pelvis-upper-trunk patterns.     

Developmental dynamics between mathematical performance,task motivation,and teachers' goals during the transition to primary school

Background. It has been suggested that children's learning motivation and interest in a particular subject play an important role in their school performance, particularly in mathematics. However, few cross‐lagged longitudinal studies have been carried out to investigate the prospective relationships between academic achievement and task motivation. Moreover, the role that the classroom context plays in this development is largely unknown. Aims. The aim of the study was to investigate the developmental dynamics of maths‐related motivation and mathematical performance during children's transition to primary school. The role of teachers' pedagogical goals and classroom characteristics on this development was also investigated. Sample. A total of 196 Finnish children were examined four times: (0) in October during their preschool year; (1) in October and (2) April during their first grade of primary school; and (3) in October during their second grade. Method. Children's mathematical performance was tested at each measurement point. Task motivation was examined at measurement points 2, 3, and 4 using the Task‐value scale for children. First‐grade teachers were interviewed in November about their pedagogical goals and classroom characteristics. Results and conclusions. The results showed that children's mathematical performance and related task motivation formed a cumulative developmental cycle: a high level of maths performance at the beginning of the first grade increased subsequent task motivation towards mathematics, which further predicted a high level of maths performance at the beginning of the second grade. The level of maths‐related task motivation increased in those classrooms where the teachers emphasized motivation or self‐concept development as their most important pedagogical goal.     

Perfectionism and efficiency: Accuracy,response bias,and invested time in proof-reading performance

Investigating problem-solving performance, Ishida, H. (2005). College students’ perfectionism and task-strategy inefficience: Why their efforts go unrewarded? Japanese Journal of Social Psychology, 20, 208–215. Found high levels of perfectionism were associated with lower efficiency. Aiming to replicate and further explore this finding, the present study investigated how two dimensions of perfectionism (high standards, discrepancy between expectations and performance) predicted efficiency in proof-reading performance. N = 96 students completed a proof-reading task involving the detection of spelling, grammar, and format errors. When error-detection performance was subjected to signal detection analysis, high standards correlated positively with the number of incorrectly detected errors (false alarms). Moreover, when task-completion time was taken into account, high standards were negatively correlated with efficiency (accuracy/time). In comparison, discrepancy correlated negatively with the number of correctly detected errors (hits) and positively with a conservative response bias. The findings show that perfectionistic standards are associated with reduced efficiency demonstrating the importance of considering invested time, errors, and response bias when investigating the relationship between perfectionism and performance.     

Nonlinear visuomotor transformations: Locus and modularity

Participants in two experiments moved a mouse-like device to the right to move a cursor on a computer screen to a target position. The cursor was invisible during motion but reappeared at the end of each movement. The relationship between the amplitudes of the cursor movement and the mouse movement was exponential in Experiment 1 and logarithmic in Experiment 2 for two groups of participants, while it was linear for the control groups in both experiments. The results of both experiments indicate that participants adjusted well to the external transformation by developing an internal model that approximated the inverse of the external transformation. We introduce a method to determine the locus of the internal model. It indicates that the internal model works at a processing level that either preceded specification of movement amplitude, or had become part of movement amplitude specification. Limited awareness of the nonlinear mouse–cursor relationship and the fact that a working-memory task had little effect on performance suggest that the internal model is modular and not dependent on high-level cognitive processes.     

Nonlinear visuomotor transformations: locus and modularity

Participants in two experiments moved a mouse-like device to the right to move a cursor on a computer screen to a target position. The cursor was invisible during motion but reappeared at the end of each movement. The relationship between the amplitudes of the cursor movement and the mouse movement was exponential in Experiment 1 and logarithmic in Experiment 2 for two groups of participants, while it was linear for the control groups in both experiments. The results of both experiments indicate that participants adjusted well to the external transformation by developing an internal model that approximated the inverse of the external transformation. We introduce a method to determine the locus of the internal model. It indicates that the internal model works at a processing level that either preceded specification of movement amplitude, or had become part of movement amplitude specification. Limited awareness of the nonlinear mouse-cursor relationship and the fact that a working-memory task had little effect on performance suggest that the internal model is modular and not dependent on high-level cognitive processes.     

反馈对注意缺损多动障碍儿童错误监控能力的影响

研究选取了注意缺损多动障碍(ADHD)儿童39名,正常儿童40名,采用两项选择任务,考察在无反馈和有反馈的情况下,ADHD儿童的错误监控能力是否存在缺损。结果发现,(1)无论是否提供反馈,与正常儿童相比,ADHD儿童的错误察觉能力正常,但是错误更正能力落后,这可能是由于ADHD儿童动作调节控制能力落后导致的;(2)反馈提高了ADHD儿童和正常儿童的认知加工速度,但同时降低了他们的警醒水平,导致错误监控能力下降。     

Career decidedness as a predictor of subjective well-being

Forming, pursing, and achieving life tasks constitute important determinants of subjective well-being (SWB). A principal life task for emerging adults involves deciding about career goals. Prior research indicates that depression predicts SWB and may be linked to lower levels of career decidedness. We tested whether or not career decidedness predicts SWB above and beyond the influence of depression and other personality traits. We also examined whether or not career decidedness partially mediates depression's influence on SWB when controlled for personality effects. Undergraduate students (N = 181; 65% female, 52% Asian) responded to measures of career decidedness, SWB, and personality. Results largely confirmed predictions. A partial mediator model indicated a direct relationship between decidedness and SWB not moderated by grade level, and an inverse relationship between the depression facet of neuroticism and both career decidedness and SWB. Findings further support career interventions to increase decidedness during the first year of college.     

How do use and comprehension of mental-state language relate to theory of mind in middle childhood?

This study investigates the relationship between mental-state language and theory of mind in primary school children. The participants were 110 primary school students (mean age = 9 years and 7 months; SD = 12.7 months). They were evenly divided by gender and belonged to two age groups (8- and 10-year-olds). Linguistic, metacognitive and cognitive measures were used to assess the following competencies: verbal ability, use of mental-state terms, understanding of metacognitive language, understanding of second-order false beliefs, and emotion comprehension. Correlations between children’ use of mental-state language and their performance on theory-of-mind tasks were moderate, whereas correlations between children's comprehension of such language and ToM abilities were high. In addition, regression analyses showed that comprehension of metacognitive language was the variable which best explained children's performance on both false belief tasks and an emotion comprehension test when verbal ability and age were controlled for.