Practice variability and children's motor behavior

This research investigated Schmidt's variability-of-practice prediction and the breadth-of-a-movement class. Schmidt's hypothesis was tested by varying the parameters of ball and distance in overarm throwing. Breadth-of-a-movement class was tested by employing two novel tasks not previously used in variability-of-practice designs. 203 kindergarten and first-grade subjects were randomly assigned to one of four conditions, three experimental and one control. Experimental subjects performed 45 trials in their respective training conditions, weight, distance, weight/distance, in one session. Two novel striking tasks were administered to all subjects pre- and posttest to assess the variability-of-practice hypothesis, and the generalizability of overarm throwing and striking. Variability-of-practice in the overarm throw appeared to strengthen the striking schemas of the kindergarten boys. Results suggest some support for the inclusion of throwing and striking in a single-movement class. The concept, breadth of movement class, however, requires further study.     

Stimulus segmentation in the visual search task

Four experiments were conducted in order to study the segmentation process in a visual search task with relevant stimuli (target and distractors) randomly distributed among textural elements. The basic idea was that a parallel segmentation process of the relevant stimuli would contribute to the overall reaction time independently of the contribution of the number of relevant stimuli. In the first experiment, with relevant stimuli and textural elements that differed in the orientation of their component lines, texture presence interacted with number of relevant stimuli and with target presence. These results were not favorable to the parallel segmentation hypothesis. In the second and third experiments, in which the relevant and the textural stimuli differed in orientation and in the luminance contrast of their component lines, the results support a parallel segmentation process for the higher contrast conditions. In these experiments, the effect of texture presence was greater on target-absent than on target-present trials. Experiment 4 shows that the search can be restricted to the high-contrast relevant stimuli when the number of these stimuli is constant and the number of textural stimuli changes from trial to trial. The present results suggest that the relevant stimuli can be segmented in parallel and then submitted to a restricted analysis, even when they are scattered among textural stimuli.     

Experimentally manipulated change in children's proactive and reactive aggressive behavior

The current study assessed the effectiveness of two behavior manipulations created to differentially lower aggressive responses in a laboratory task. It was hypothesized that the reactive anger manipulation would have the greatest effect for reactive aggressive behavior and the instrumental manipulation would significantly affect proactive aggressive behavior and slightly affect the reactive behavior. Fifty participants played pinball in competition for points against an unknown peer, whose responses were actually controlled by the experimenter. Participants could push a noise button, sending the peer an annoying noise; a tilt button, interfering with the opponent's game; or a no answer button, offering a pro‐social alternative to aggression. After playing four rounds, participants were randomly assigned to either a reactive anger or a positive instrumental manipulation group; they then played pinball again for four rounds. Results indicate that the instrumental manipulation significantly lowered aggressive responses for both reactive and proactive behavior. The reactive manipulation effected aggressive responses only for use of the noise button and produced significantly lower levels of anger. Aggr. Behav. 29:215–227, 2003. © 2003 Wiley‐Liss, Inc.     

Stimulus salience and relational task performance

Previous research has inferred relational processing from infants' increased attention to stimuli containing different elements following habituation to a series of stimuli containing identical elements. This finding was replicated, but infants were also found to prefer the different-element stimuli without prior habituation. Infants' performance on this task may be attributed to stimulus salience rather than relational processing.     

Stimulus and response chunking in the Hebb Digits task

Using the Hebb Digits task, an incidental sequential learning paradigm, the effects of chunking of both the presentation and response phases of performance were examined. In the first experiment, consistent stimulus chunking increased learning, and performance was at an equivalent level to this when consistent chunking of both stimuli and responses was present. Consistent chunking of the responses alone did not significantly improve learning over a baseline condition where neither stimuli nor responses were chunked. The disruption of response organization in a second experiment, through a random response condition, failed to impact learning in non-chunked and stimulus chunked conditions. A third experiment found that response chunking did benefit learning in a condition where stimuli were presented in random chunks. A final experiment suggested extended processing of the digits could not account for performance gains in the stimulus chunking condition. Overall, the results suggest that the enhanced effects of chunking on learning were stimulus-driven rather than response-driven, except under conditions that constrained a consistent pattern of stimulus organization.     

Mothers' beliefs and children's long-term cognitive change: A developmental task interpretation

A longitudinal study was used to explore the following hypotheses concerning the relation between mothers' beliefs, their use of high distancing utterances and children's cognitive development: (1) beliefs moderate the impact of high-distancing utterances on children's development, and (2) beliefs reflect mothers' normative expectations that motivate themselves and their children to try to satisfy them. The participants consisted of 34 children and their mothers and teachers. Results for the motherchild dialogues indicated that the distancing–cognitive performance relationship was strongest for children whose mothers had the most positive beliefs. In addition, mothers' beliefs about a 4-year-old child were more strongly related to children's cognitive performance at ages 6 and 10 than to cognitive performance at age 4. Characteristics of both verbal parent–child and verbal teacher–child interactions at age 4 supported a developmental task interpretation of these findings.     

What response times tell of children's behavior on the balance scale task

Analysis of accuracy of responses to balance scale problems gives a global idea of the cognitive processes that underlie problem-solving behavior on this task. We show that response times (RTs) provide additional detailed information about the kind and duration of these processes. We derive predictions about the RTs from Siegler's (1981) model for the balance scale task, including the counterintuitive prediction that young adults are slower than children in solving particular balance scale problems. The predictions were tested in a study in which 191 6- to 22-year-old participants were presented with a computerized balance scale task. RTs were analyzed with regression models. In addition to qualitative differences between items, we also modeled quantitative differences between items in the regression models. Analyses supported the predictions and provided additional knowledge on the rules. Rule II was reformulated as a rule that always involves the encoding, but not always the correct application of the distance cue. RTs provided evidence for the use of a buggy-rule and not an addition-rule. Finally, a relation between rule inconsistency and increased RT was found.     

Perceptual effect on motor learning in the serial reaction-time task

Although the Serial Reaction-Time Task has been an effective tool in studying procedural learning, there is still a debate as to whether learning in the task is effector-based, stimulus-based, or response-based. In this article, the authors contribute to this debate by contrasting response- and stimulus-based learning by manipulating them selectively and simultaneously. Results show that (a) participants learned response sequences in the absence of stimulus-specific perceptual sequence information but (b) not stimulus sequences without corresponding response information. In a third condition, response sequence and stimulus frequency information were in conflict, and each effect decreased learning in the other domain. Overall, our findings show that learning in these tasks is primarily motor-based, but it is also constrained by relatively salient perceptual information. Together with earlier findings in the literature, the findings also suggest a task and stimulus-arrangement-specific interaction between motor and perceptual learning, where relevance and salience of the specific information plays a crucial role.     

Attention as a cueing function during kindergarten children's dimensional change task performance

The purpose of this experiment is to test whether shift flexibility in kindergarten children is a joint function of rule‐usage and inhibition of attention. Sixty‐six children were given either a distraction or facilitation condition in a computerized version of the dimensional change card sort task. In the distraction condition, the background of the post‐shift matching stimulus was inconsistent with the relevant matching dimension. In the facilitation condition, the background of the post‐shift matching stimulus was consistent with the relevant matching dimension. Results revealed that children made few errors in the standard version of the shift task, thereby supporting Cognitive complexity and control theory's contention that 5‐year‐old children shift easily across dimensions due to their use of higher‐order setting rules to solve contradictions. The proportion of errors increased however in the distraction condition suggesting that attention to the background interfered with children's ability to shift between dimensions. Therefore, these data provide evidence that refocusing attention to dimensions along with rule‐use processes affect shift flexibility and argue for the inclusion of both factors into theoretical accounts of shift performance. Copyright © 2009 John Wiley & Sons, Ltd.     

Stimulus similarity decrements in children's working memory span

Two experiments investigated the impact of the relationship between processing and storage stimuli on the working memory span task performance of children aged 7 and 9 years of age. In Experiment 1, two types of span task were administered (sentence span and operation span), and participants were required to recall either the products of the processing task (sentence-final word, arithmetic total) or a word or digit unrelated to the processing task. Experiment 2 contrasted sentence span and operation span combined with storage of either words or digits, in tasks in which the item to be remembered was not a direct product of the processing task in either condition. In both experiments, memory span was significantly greater when the items to be recalled belonged to a different stimulus category from the material that was processed, so that in sentence span tasks, number recall was superior to word recall, and in operation span tasks, word recall was superior to number recall. Explanations of these findings in terms of similarity-based interference and response competition in working memory are discussed.     

Stimulus comparison strategies and task demands in successive discrimination

This research isolates two distinct strategies used to identify stimuli presented at different rates in successive discrimination tasks. The short-term strategy (used at rapid rates) compares current stimuli to immediately prior stimuli present in sensory or other short-term storage, whereas the long-term strategy (used at slow rates) compares current stimuli to a standard stimulus in long-term memory. In Experiment 1, subjects detected a medium-duration tone amid both long and short distractors. Analysis of false alarms indicated that strategy choice is strongly influenced by event rate, and therefore by the presence or absence of sensory traces of preceding stimuli. Experiment 2 was designed to force subjects to use the short-term strategy (to detect targets, present stimuli had to be compared to their immediate predecessors), and varied the event rate. Subjects were able to maintain a high level of performance throughout the task only at the fastest event rate. This pattern of results suggested that when the task demanded it, subjects could use a particular strategy, but if the event rate (and consequently the availability or otherwise of relevant memorial traces) was not favourable to that strategy, then performance was disadvantaged.     

Stimulus and response anticipation in a serial reaction task

When subjects are confronted with sequences of stimuli that are constructed according to certain rules, they tend to improve their performance in terms of lower error rates and/or faster reaction times as compared to random sequences of the same stimuli, even if they are not able to report the regularities of events.     

A neo-Piagetian investigation of the serial position effect in children's motor learning

Children's serial motor skill acquisition was studied within a neo-Piagetian framework. High and low M-processors performed on a curvilinear repositioning task. A primacy-recency effect was evidenced for both groups on the age-related task, while a recency effect occurred for only the high M-processors on the task one stage beyond the developmental processing capacity of the subjects. High M-processors were more accurate and less variable than low M-processors. Although low M-processors performed better on the more complex task than on the simpler one, their performance never exceeded that of the high M-processors. Implications of these results for future research were discussed.