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.     

On the Nature of the Probe Reaction-Time Task to Uncover the Attentional Demands of Movement

McLeod (1980) reported some findings which showed that no phase of a movement was more attention-demanding than the other phases, contrary to all the results previously reported (e.g., Ells, 1973; Glencross, 1980). However, McLeod used a paradigm in which the two tasks were serial. Each task consisted of a series of 50 reaction time (RT) trials and/or 50 aiming movement trials. In addition to this, the interval of time between a response and the following signal within each series was constant. In order to try to replicate McLeod’s findings, two experiments were conducted in which the response-signal interval was manipulated. The hypothesis was that time certainty associated with a constant interval would facilitate the allocation of time and would thus artificially reduce the interference between tasks. In Experiment I, manual responses were used for the RT task; in Experiment II, they were vocal. Manipulation of the response-signal interval does not change one of the conclusions reached by McLeod: when the RT task involves vocal responses and the results on the RT task are analyzed in terms of response rather than stimulus arrival during the movement, then there is no phase of the movement which is more attention-demanding than the other phases. However, the results of Experiment II in which both the vocal RT task and the movement task significantly deteriorated in the dual-task condition were taken as an indication that the movement studied involved central attentional demands.     

On the nature of the probe reaction-time task to uncover the attentional demands of movement

McLeod (1980) reported some findings which showed that no phase of a movement was more attention-demanding than the other phases, contrary to all the results previously reported (e.g., Ells, 1973; Glencross, 1980). However, McLeod used a paradigm in which the two tasks were serial. Each task consisted of a series of 50 reaction time (RT) trials and/or 50 aiming movement trials. In addition to this, the interval of time between a response and the following signal within each series was constant. In order to try to replicated McLeod's findings, two experiments were conducted in which the response-signal interval was manipulated. The hypothesis was that time certainty associated with a constant interval would facilitate the allocation of time and would thus artificially reduce the interference between tasks. In Experiment 1, manual responses were used for the RT task; in Experiment II, they were vocal. Manipulation of the response-signal interval does not change one of the conclusions reached by McLeod: when the RT task involves vocal responses and the results on the RT task are analyzed in terms of response rather than stimulus arrival during the movement, then there is no phase of the movement which is more attention-demanding than the other phases. However, the results of Experiment II in which both the vocal RT task and the movement task significantly deteriorated in the dual-task condition were taken as an indication that the movement studied involved central attentional demands.     

The role of working memory capacity in implicit and explicit sequence learning of children: Differentiating movement speed and accuracy

This study investigated the role of working memory capacity on implicit and explicit motor sequence learning in young children. To this end, a task was utilized that required a gross motor response (flexing the elbow) and that could differentiate between movement speed (i.e., reaction time and movement time) and movement accuracy. Children aged 7–9 years practiced a serial reaction time task that involved the production of a fixed sequence of elbow flexions of prescribed magnitude across two consecutive days. Children in the explicit group were informed about the presence of the sequence and were shown this sequence, while children in the implicit group were not made aware of the sequence. Additionally, children's verbal and visuospatial working memory capacity was assessed. Results of day 1 regarding movement speed revealed no evidence of sequence learning for either group, but movement accuracy results suggested that sequence learning occurred for the implicit group. For both groups, only improvements in movement accuracy were consolidated on day 2, indicating both general and sequence specific learning. Working memory capacity did not correlate with learning in either of the groups. Children in the explicit group accumulated more sequence knowledge compared to children in the implicit group, but this knowledge did not translate to more or better sequence learning. The minimal differences found between the implicit and explicit condition and the absence of a role for working memory capacity add to the increasing evidence that the observed differences between implicit and explicit sequence learning in adults may be less distinct in children.     

The effect of state anxiety on the online and offline control of fast target-directed movements

In target-directed aiming, afferent information is used to adjust limb trajectories during movement execution (i.e. online) and to enhance the programming of subsequent trials (i.e. offline). The objective of the present study was to determine the influence of state anxiety on both online and offline afferent information processing for the first time. Participants practiced either a directional aiming task (Experiment 1) or an amplitude aiming task (Experiment 2) without anxiety before being transferred to a high anxiety condition. In both experiments, results revealed that anxiety resulted in a decrement in performance. Furthermore, use of afferent information to adjust movement trajectories online was disrupted when movements were performed with anxiety, whereas there were no differences in the offline processing of afferent information between the low anxiety and high anxiety conditions.     

Exploring the relationship between new word learning and short-term memory for serial order recall,item recall,and item recognition

We reexplored the relationship between new word learning and verbal short-term memory (STM) capacities, by distinguishing STM for serial order information, item recall, and item recognition. STM capacities for order information were estimated via a serial order reconstruction task. A rhyme probe recognition task assessed STM for item recognition. Item recall capacities were derived from the proportion of item errors in an immediate serial recall task. In Experiment 1, strong correlations were observed between item recall and item recognition, but not between the item STM tasks and the serial order task, supporting recent theoretical positions that consider that STM for item and serial order rely on distinct capacities. Experiment 2 showed that only the serial order reconstruction task predicted independent variance in a paired associate word–nonword learning task. Our results suggest that STM capacities for serial order play a specific and causal role in learning new phonological information.     

The irrelevant sound effect in short-term memory: Is there developmental change?

With two experiments, effects of irrelevant speech and classroom noise on serial recall of common nouns presented pictorially were investigated in children and adults. Experiment 1 used fixed list lengths for children (first graders) and adults. Experiment 2 used list lengths adjusted to participants' (second–third graders, adults) individual spans. In both experiments, children and adults were equally impaired by irrelevant speech. This contrasts with a related study (differences in methodology) by Elliott (2002), who reported severe increase in the detrimental impact of irrelevant speech with decreasing age. In both experiments, classroom noise had no effect in overall analyses. For Experiment 1, however, separate group analyses revealed impairment in children. Results suggest that effects of irrelevant sounds on serial recall stem from two separate mechanisms: Specific interference due to the sounds' automatic access to short-term memory, and/or attention capture. Only for the latter there is developmental change.     

Age-related changes in children's use of external representations.

This study explored children's use of external representations. Experiment 1 focused on representations of self: Self-recognition was assessed by a mark test as a function of age (3 vs. 4 years), delay (5 s vs. 3 min), and media (photographs vs. drawings). Four-year-olds outperformed 3-year-olds; children performed better with photographs than drawings; and there was no effect of delay. In Experiment 2, 3- and 4-year-olds used a delayed video image to locate a sticker on themselves (self task) or a stuffed animal (other task). The 2 tasks were positively correlated with age and vocabulary partialed out. Experiment 3 used a search task to assess whether children have particular difficulty using external representations that conflict with their expectations: 3- and 4-year-olds were informed of an object's location verbally or through video: on half of the trials, this information conflicted with children's initial belief. Three-year-olds performed worse than 4-year-olds on conflict trials, indicating that assessments of self and other understanding may reflect children's ability to reason about conflicting external representations.     

What can we learn about immediate memory from the development of children's free recall?

We ask the question: Which aspects of immediate memory performance improve with age? In two studies, we reexamine the widely held view that primary memory capacity estimates derived from children's immediate free recall are age invariant. This was done by assessing children's immediate free-recall accuracy while also measuring the order in which they elected to recall items (Experiment 1) and by encouraging children to begin free recall with items from towards the end of the presented list (Experiment 2). Across samples aged between 5 and 8 years we replicated the previously reported age-related changes in free-recall serial position functions when aggregated across all trials of the standard task, including an absence of age differences in the recency portion of this curve. However, we also show that this does not reflect the fact that primary memory capacity is constant across age. Instead, when we incorporate order of report information, clear age differences are evident in the recall of list-final items that are output at the start of a participant's response. In addition, the total amount that individuals recalled varied little across different types of free-recall tasks. These findings have clear implications for the use of immediate free recall as a means of providing potential indices of primary memory capacity and in the study of the development of immediate memory.     

The role of timing deviations and target position uncertainty on temporal attending in a serial auditory pitch discrimination task

Listeners were presented with sequences of tones that ascended in semitone intervals. On each trial a single target tone in the sequence was displaced in pitch, and listeners were required to indicate whether the target tone was higher or lower than its normal pitch. Task constraints, specifically target serial position uncertainty and the probabilistic relationship between time deviations and target tones, were varied in order to determine the impact of task constraints on temporal attending strategy. When listeners had no advance knowledge of the serial position of the target, and early and late targets provided information regarding target serial position, performance was better for early and late target trials than for on-time target trials (Experiment 1). When listeners had no advance knowledge of the serial position of the target, and early and late temporal deviations provided no information regarding target serial position, performance for late target trials was superior to that for early and on-time target trials (Experiment 2). Finally, when target serial position uncertainty was eliminated, performance was equivalent across all three levels of target timing (early, on time, late). The results indicate that performance profiles based on stimulus timing properties are affected by various task constraints as well as by stimulus properties.     

汉语发展性阅读障碍儿童的视知觉学习*

研究采用知觉学习经典范式中的视觉搜索任务探讨汉语发展性阅读障碍儿童的知觉学习过程。研究考察了阅读障碍儿童与正常儿童在简单搜索任务、复杂搜索任务和限制时间的复杂搜索任务上的知觉学习特点。结果发现,阅读障碍儿童在复杂搜索任务中初始搜索时间显著长于正常控制组;在限制时间的复杂搜索任务中更进一步发现阅读障碍儿童的反应正确率显著低于正常控制组儿童;而且两组儿童视觉搜索任务的正确率与汉语阅读的识字量成绩存在显著相关。上述结果表明,汉语发展性阅读障碍儿童存在复杂搜索的知觉学习缺陷,这种缺陷可能在某种程度上与儿童的阅读技能发展有关。     

Multiple roles for time in short-term memory: evidence from serial recall of order and timing

Three experiments are reported that examine the relationship between short-term memory for time and order information, and the more specific claim that order memory is driven by a timing signal. Participants were presented with digits spaced irregularly in time and postcued (Experiments 1 and 2) or precued (Experiment 3) to recall the order or timing of the digits. The primary results of interest were as follows: (a) Instructing participants to group lists had similar effects on serial and timing recall in inducing a pause in recall between suggested groups; (b) the timing of recall was predicted by the timing of the input lists in both serial recall and timing recall; and (c) when the recall task was precued, there was a tendency for temporally isolated items to be more accurately recalled than temporally crowded items. The results place constraints on models of serial recall that assume a timing signal generates positional representations and suggest an additional role for information about individual durations in short-term memory.     

Sequence‐specific procedural learning deficits in children with specific language impairment

This study tested the procedural deficit hypothesis of specific language impairment (SLI) by comparing children's performance in two motor procedural learning tasks and an implicit verbal sequence learning task. Participants were 7‐ to 11‐year‐old children with SLI (n = 48), typically developing age‐matched children (n = 20) and younger typically developing children matched for receptive grammar (n = 28). In a serial reaction time task, the children with SLI performed at the same level as the grammar‐matched children, but poorer than age‐matched controls in learning motor sequences. When tested with a motor procedural learning task that did not involve learning sequential relationships between discrete elements (i.e. pursuit rotor), the children with SLI performed comparably with age‐matched children and better than younger grammar‐matched controls. In addition, poor implicit learning of word sequences in a verbal memory task (the Hebb effect) was found in the children with SLI. Together, these findings suggest that SLI might be characterized by deficits in learning sequence‐specific information, rather than generally weak procedural learning.     

Reliance on visual and verbal information across ontological kinds: What do children know about animals and machines?

In two experiments, we systematically examined the reliance on visual (external shape and features) and verbal (origins and internal structure) information in isolation, and together in the identification of animals and machines by 3-, 4-, and 5-year-olds, and adults. Experiment 1 examined the use of visual and verbal information independently in a visual classification task, a verbal classification task, and an induction task. Experiment 2 examined the relative weighting of visual and verbal information in an induction task and a categorization task. The three most important findings from Experiment 1 were that (a) children and adults can use either visual or verbal information to distinguish animals from machines; (b) all age groups classified items with mixed visual information as machines, a tendency that increased with age; and (c) with age, children became increasingly able to induce non-obvious properties, especially the non-obvious properties of machines. The findings from Experiment 2 indicate that the youngest and oldest participants relied on both visual and verbal information in the identification of animals and machines in categorization and induction tasks. Five-year-olds, however, relied only on visual information. As in Experiment 1, we observed a tendency to judge items with contrasting information as machines, suggesting that individuals utilize a more strict definition (both visually and verbally) for the category of animals. We discuss the implication of these results with respect to developmental differences in the use of perceptual and conceptual information across the ontological distinction between artifacts and natural kinds.     

Exploring the contributions of declarative and procedural information to training: A test of the procedural reinstatement principle

According to the procedural reinstatement principle, procedural information leads to strong retention but limited transfer, whereas declarative information leads to poor retention but robust transfer. To test this principle in Experiment 1, participants were trained to perform a serial response task in one of 3 conditions (declarative, procedural, mixed) and were subsequently tested in either the same or another condition. Required responses were identical in the three conditions; they differed only in the emphasis given to declarative or procedural information. Consistent with the procedural reinstatement principle, in terms of response time procedural information was more durable than declarative information. In Experiment 2, transfer was assessed using procedural and declarative conditions, but participants transferred between response sequences within those conditions. Although there was transfer in response time between sequences with procedural information, the greatest magnitude of transfer was found in one direction with declarative information, consistent with the procedural reinstatement principle.     

Phonological deficits: Beneath the surface of reading-acquisition problems

Summary In Experiment 1, the performance of young retarded readers on speech-segmentation tasks was compared with the performance of normal subjects matched for chronological age (CA) and with subjects matched for reading age (RA). Retarded readers were poorer than both control groups in consonant deletion, while there was no difference between the groups on a rhyme-judgement task and a syllabic-vowel-reproduction task. In Experiment 2, another group of reading retarded children was compared with CA and RA controls on the classification of pseudowords, either by common phoneme or by overall phonetic similarity. The retarded readers made fewer classifications based on common phoneme than both control groups, while there was no difference between the groups in classifications based on overall phonetic similarity. In Experiment 3, adult developmental dyslexics were compared with normal adults in the tasks of Experiments 1 and 2. The dyslexics made fewer classifications based on a common phoneme than the normals, while no difference was found in classifications based on overall phonetic similarity.     

面孔吸引力和信息正确性对幼儿选择性信任的影响

实验1采用3×2×2 的混合设计, 考察4~6岁幼儿获取全新信息时基于面孔吸引力的选择性信任及其特点。结果显示：(1) 4~6岁的男孩和女孩均表现出对高面孔吸引力者的选择性信任。(2)在选择性信任程度方面：5岁比4岁高, 而4岁和6岁之间、5岁和6岁之间则相同; 女孩在询问任务中比男孩表现出更高的选择性信任, 在赞同任务中则相同。那么, 幼儿的这种选择性信任是否受到信息正确性的调节?为此, 实验2采用2×3的被试间设计, 探讨信息提供者提供信息的正确性对4~6岁幼儿基于面孔吸引力的选择性信任的影响。结果显示：在正确性为50% vs. 50%条件下, 幼儿未对信息提供者产生选择性信任; 在正确性为25% vs. 75%条件下, 幼儿对提供较大正确性信息的低面孔吸引力者产生了选择性信任。研究结果表明：(1)在信息缺乏时, 4~6岁幼儿普遍存在有偏见的选择性信任; 女孩比男孩更易受到社会偏见因素的影响。(2)在信息明确时, 4~6岁幼儿也能做出相对理性的选择性信任。     

Irrelevant response effects improve serial learning in serial reaction time tasks

Tones were introduced into a serial reaction time (SRT) task to serve as redundant response effects. Experiment 1 showed that the tones improved serial learning with a 10-element stimulus sequence, but only if the tone effects were mapped onto the responses contingently. Experiment 2 demonstrated that switching to noncontingent response-effect mapping increased SRT only when participants had previously adapted to contingent response-effect mapping. In Experiment 3, the beneficial influence of contingent tone effects on serial learning occurred only when there was sufficient time between the response effects and the next imperative stimuli. The results are discussed in terms of the ideomotor principle. It is claimed that an internal representation of the to-be-produced tone effects develops and gains control over the execution of the response sequence.     

Multi-Task Study of the Effects of Task Load and Gender on the Development of Visual Field Asymmetries

This study was designed to examine whether the developmental course of visual hemispheric asymmetry is affected by task load and whether gender differences occur with age. Three experiments were performed according to the additive structure of reaction time: “go/no-go” task, “choice-reaction-time” task, and “category-sort” task. Children in three different age groups (7- to 8-years, 10 years, and 13 year olds) were presented lists of words using a visual half-field procedure. Results revealed that in the go/no-go task (Experiment 1), left hemispheric superiority for processing of word stimuli was evident at all three developmental ages, but no gender differences appeared. However, in the choice-reaction-time task (Experiment 2), and the category-sort task (Experiment 3), left hemispheric superiority was displayed by 7- to 8- and 10-year-old males, but not by 13-year-old males. In contrast, girls did not show the left hemispheric advantage at any of the developmental ages. It was concluded that visual hemispheric asymmetry exists in children at an early age, but the magnitude of asymmetry is dependent on age, gender, and task load.     

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.