Procedural learning,consolidation, and transfer of a new skill in Developmental Coordination Disorder

The aim of this study was to explore the differences in procedural learning abilities between children with DCD and typically developing children by investigating the steps that lead to skill automatization (i.e., the stages of fast learning, consolidation, and slow learning). Transfer of the skill to a new situation was also assessed. We tested 34 children aged 6–12 years with and without DCD on a perceptuomotor adaptation task, a form of procedural learning that is thought to involve the cerebellum and the basal ganglia (regions whose impairment has been associated with DCD) but also other brain areas including frontal regions. The results showed similar rates of learning, consolidation, and transfer in DCD and control children. However, the DCD children's performance remained slower than that of controls throughout the procedural task and they reached a lower asymptotic performance level; the difficulties observed at the outset did not diminish with practice.     

Externalized memory in slime mould and the extended (non-neuronal) mind

The hypothesis of extended cognition (HEC) claims that the cognitive processes that materially realise thinking are sometimes partially constituted by entities that are located external to an agent’s body in its local environment. We show how proponents of HEC need not claim that an agent must have a central nervous system, or physically instantiate processes organised in such a way as to play a causal role equivalent to that of the brain if that agent is to be capable of cognition. Focusing on the case of spatial memory, we make our argument by taking a close look at the striking example of Physarum Polycephalum plasmodium (i.e., slime mould) which uses self-produced non-living extracellular slime trails to navigate its environment. We will argue that the use of externalized spatial memory by basal organisms like Physarum is an example of extended cognition. Moreover, it is a possible evolutionary precursor to the use of internal spatial memory and recall in animals thus demonstrating how extended cognition may have emerged early in evolutionary history.     

“Changing the Text”: Modeling Council Capacity to Produce Institutionalized Change

Collaboration is a ubiquitous approach to change, but is notoriously difficult and not definitively linked to desirable outcomes. Not surprisingly, the collaboration literature is replete with numerous facilitators and barriers to collaborative efforts. The current study aimed to develop a parsimonious model of factors influencing the success of collaborative efforts both internal and external to the council, including, (a) features of the council environment, (b) intermediate outcomes including the empowerment of members in the council context and the degree to which councils have generated social capital and (c) the extent to which collaborative efforts are occurring in a community context supportive of their aims. In particular, this study examines whether these factors affect the extent to which councils are positioned to achieve institutionalized change, or changes "in the text" that govern front line providers' (e.g., police, advocates) practices in the community response to intimate partner violence. Results suggest that perceived member empowerment, generation of social capital, and supportive community context are the most important predictors of the extent to which councils foster shifts in institutionalized change. Features of the council environment are only indirectly related to the degree to which institutionalized change is ultimately fostered as mediated by the generation of social capital. This suggests that the ability of members to act as change agents and the extent to which those in power support council efforts figure more prominently to facilitate or constrain council efforts than council functioning itself.     

Norms and conventions

One can think of the traditional logic of blame as involving three intuitively plausible claims: (1) blame is justified only if one is deserving of blame, (2) one is deserving of blame only if one is relevantly in control of the relevant causal antecedents, and (3) one is relevantly in control only if one has libertarian freedom. While traditional compatibilism has focused on rejecting either or both of the latter two claims, an increasingly common strategy is to deny the link between blame and desert expressed in (1). While I think there is something right about many of these accounts of blame, I deny that the logic of blame can be divorced from the logic of desert. On my view, blame does have a conceptual connection to desert, but its justification is practical rather than theoretical, as the libertarian condition is a matter of adopting a stance towards a person rather than having a belief about her and the “true” causes of her action. I argue that blame fundamentally requires interacting with a person from the participant perspective and that the participant perspective, understood in terms of second-personal address, involves an ontological commitment to freedom.     

基于直线临摹的ADHD儿童眼手协调能力研究

ADHD儿童在精细动作方面通常伴随眼手协调运动障碍。以往采用的研究方法多为定性研究,且未在ADHD儿童的运动协调性与同龄正常儿童的差异上得出统一结论。本研究针对精细动作中眼手协调能力进行定量分析。实验要求被试在计算机触摸屏上分别临摹水平线、垂直线和斜线,通过记录临摹直线与呈现直线的偏差程度和拐点数,以分析ADHD儿童眼手协调能力与正常儿童之间的差异。结果表明,ADHD儿童在眼手协调和空间知觉能力上与正常儿童存在显著性差异。此外,本研究表明,改进的定量方法具有良好的可行性。     

Catching With Both Hands: An Evaluation of Neural Cross-Talk and Coordinative Structure Models of Bimanual Coordination

Kelso, Southard, and Goodman (1979) and Marteniuk and MacKenzie (1980) have each proposed a different theoretical model for bimanual coordination. In the model of Kelso et al., a close temporal relationship between the hands in a bimanual task is predicted, even when each hand is required to move different distances. In Marteniuk and MacKenzie's model, separate motor commands are issued so that each limb will arrive simultaneously at the specified movement endpoint, leading to low temporal associations between limbs. In most previous work on bimanual coordination, manual aiming tasks with differing constraints have been used by subjects in individual studies. In this study, the usefulness of existing models for predicting performance in a real-world catching task in which the required movement pattern was constrained by ball flight characteristics was examined. Eleven university students caught tennis balls with both hands in the following 3 conditions: Condition 1. Ball projected to the right shoulder area (left hand moved a greater distance than the right); Condition 2. Ball projected to center of the chest area, (both hands moved same distance); and Condition 3. Ball projected to left shoulder area (right hand moved a greater distance). Kinematic data (time to peak velocity, movement initiation time) indicating significant cross-correlations between the left and right limbs in all 3 conditions concurred with the data of Kelso et al. (1979) on manual aiming. Timing appeared to be an essential variable coordinating bimanual interceptive actions. Although the limbs moved at different speeds when each was required to move different distances, times to peak velocity showed strong associations, suggesting the presence of a coordinative structure.     

Spatial Conceptual Influences on the Coordination of Bimanual Actions: When a Dual Task Becomes a Single Task

When the left and right hands produce 2 different rhythms simultaneously, coordination of the hands is difficult unless the rhythms can be integrated into a unified temporal pattern. In the present study, the authors investigated whether a similar account can be applied to the spatial domain. Participants (N = 8) produced a movement trajectory of semicircular form in single-limb and bimanual conditions. In the bimanual tasks, 1 limb moved above the other in the frontal plane. Bimanual unified tasks were constructed so that the spatial paths to be produced by the 2 limbs could be easily conceptualized as parts of a unified circle pattern. Bimanual distinct tasks availed a less obvious spatial pattern that would unify the 2 tasks. Performance of the spatial patterns was more accurate in the unified task, despite similar demands placed on the coordination dynamics between the limbs in the 2 cases (e.g., the phase relations). The authors conclude that a dual task becomes a single task, and interlimb interference is reduced, when the spatial patterns produced by the 2 hands form a geometric arrangement that can be conceptualized as a unified representation.     

A Note on the Conscious Controls of Motor Units by Children Under Six

A simple form of training the conscious control of motor units in skeletal muscle has been demonstrated in a series of children under age 6. Easy boredom is the chief deterrent in the very young. So long as a child understands and cooperates, he can learn to isolate single units in a period of about 30 min.     

Moving the Arm at Different Rates: Slow Movements are Avoided

Qualitative and quantitative changes characterize locomotion and rhythmic interlimb coordination at different speeds. Legs and hands do not move more or less quickly; they also adopt different relative coordination patterns. In the present article, the authors asked whether similar transitions occur for unimanual hand movements when speed is slowed below the preferred speed. Participants moved a handheld dowel back and forth between 2 large circular targets in time with a metronome at periods between 370 ms and 1667 ms. The authors analyzed the kinematics of participants’ movements at each period and found that proportional dwell time and number of peaks in the velocity profile increased as driving periods increased. Path lengths and peak velocities remained relatively constant for driving periods exceeding 800 ms. Participants made only gradual changes to their movement parameters, so that they went from a continuous mode to a more discrete mode of behavior for longer driving periods. Thus, unlike for rhythmic bimanual movements or locomotory patterns, there are quantitative but no clear qualitative changes for unimanual movements. The results suggest that participants tried to move close to their preferred tempo at different rates, and that they avoided moving slowly.     

Bimanual Training Reduces Spatial Interference

The authors investigated whether training can reduce bimanual directional interference by using a star-line drawing paradigm, Participants (N = 30) were required to perform rhythmical arm movements with identical temporal but differing directional demands. Moreover, the effectiveness of part-task training in which each movement was practiced in isolation was compared with that of whole-task training in which only combined movements were performed. Findings revealed that bimanual training substantially reduced spatial interference, but unimanual training did not. The authors therefore concluded that the spatial coupling of the limbs is not implemented in a rigid way; instead, the underlying neural correlate can undergo plastic changes induced by training. Moreover, the practical implication that emerged from the present study is that athletic, musical, or ergonomic skills that require a high degree of interlimb coordination are best served by whole-task practice.