Why do children perseverate when they seem to know better: Graded working memory,or directed inhibition?

Children sometimes have trouble switching from one task to another, despite demonstrating an awareness of current task demands. This behavior could reflect problems either directly inhibiting previously relevant information or sufficiently activating graded working memory representations for the current task. We tested competing predictions from each account, using a computerized card-sorting task in which we assessed children’s task switching abilities and their response speed to simple questions about current task demands. All children answered these questions correctly, but children who successfully switched tasks responded more quickly to questions than did children who perseverated on previous tasks, even after factoring out processing speed and age. This reaction time difference supports graded working memory accounts, with stronger representations of current task demands aiding both task-switching and responses to questions. This result poses a challenge for directed inhibition accounts, because nothing needs to be inhibited to answer simple questions that lack conflicting information.     

Predictors of time-based prospective memory in children

This study identified age differences in time-based prospective memory performance in school-aged children and explored possible cognitive correlates of age-related performance. A total of 56 7- to 12-year-olds performed a prospective memory task in which prospective memory accuracy, ongoing task performance, and time monitoring were assessed. Additional tests of time estimation, working memory, task switching, and planning were performed. Results showed a robust relationship between age and prospective memory performance even after controlling for ongoing task performance. Developmental differences in time monitoring were also observed, with older children generally adopting a more strategic monitoring strategy than younger children. The majority of age-related variance in prospective memory task performance could be explained by cognitive resources, in particular planning and task switching. In contrast, no further independent contribution of time estimation was observed. Findings are in line with the development of strategic behavior, as well as executive functioning, in school-aged children.     

Asymmetrical switch costs in children

Switching between tasks produces decreases in performance as compared to repeating the same task. Asymmetrical switch costs occur when switching between two tasks of unequal difficulty. This asymmetry occurs because the cost is greater when switching to the less difficult task than when switching to the more difficult task. Various theories about the origins of these asymmetrical switch costs have emerged from numerous and detailed experiments with adults. There is no documented evidence of asymmetrical switch costs in children. We conducted a series of studies that examined age-related changes in asymmetrical switch costs, within the same paradigm. Similarities in the patterns of asymmetrical switch costs between children and adults suggested that theoretical explanations of the cognitive mechanisms driving asymmetrical switch costs in adults could be applied to children. Age-related differences indicate that these theoretical explanations need to incorporate the relative contributions and interactions of developmental processes and task mastery.     

Early development of subcortical regions involved in non-cued attention switching

This study examined the cognitive and neural development of attention switching using a simple forced-choice attention task and functional magnetic resonance imaging Fourteen children and adults made discriminations among stimuli based on either shape or color. Performance on these trials was compared to performance during blocked trials requiring all color or all shape discriminations. Magnetic resonance echo planar images were acquired during performance of the task. Both children and adults showed robust bilateral activity of the caudate nucleus when switching attention between color and shape discriminations that correlated negatively with mean response latency on these trials. However, neither switching costs nor caudate activity correlated with age, suggesting early development of the underlying neural circuitry involved in switching between salient stimulus sets. Overall, children and adults differed in performance and patterns of brain activity on the task, with adults responding more accurately and faster than children, and recruiting more prefrontal and parietal regions. These results suggest an important role of subcortical regions (i.e. caudate nucleus) in non-cued attention switching, with increasing recruitment of cortical regions with age.     

On the nature of the relationship between processing activity and item retention in children

The concept of working memory emphasizes the interrelationship between the transient retention of information and concurrent processing activity. Three experiments address this relationship in children between 8 and 17 years of age by examining forgetting when a processing task is interpolated between presentation and recall of the memory items. Unlike previous studies, delivery of interpolated stimuli was under computer control and responses to these stimuli were timed. There were consistent effects of the duration of the interpolated task, but no effects of either its difficulty or similarity to memory material and no qualitative developmental differences in task performance. The absence of an effect of difficulty provides no support for models of working memory in which limited capacity is shared between the dual functions of processing and storage, but is compatible with an alternative "task switching" account. However, task switching did not explain developmental differences in recall. Other aspects of the results suggest that there can be interactions between processing and storage but it is argued that these cannot be straightforwardly explained in terms of either task switching or resource sharing.     

不同特征维度下ADHD儿童的任务切换特点

本研究采用双向刺激设置,通过操纵两实验的特征维度,以考察任务维度对ADHD儿童任务切换的影响。结果发现,在两个实验中,相对于正常组儿童,ADHD儿童在任务切换上都表现出缺损。当注意维度相同时,ADHD儿童在固定顺序上的切换损耗大于随机顺序,但在跨维度任务中,ADHD儿童在固定顺序上的切换损耗则小于随机顺序,这与正常儿童的表现模式不一致。该结果表明,工作记忆会对ADHD儿童产生影响,但这取决于任务的特征维度是否一致。     

A COGNITIVE ANTHROPOLOGICAL PERSPECTIVE ON FIRST-GRADERS' CLASSIFICATIONS OF PICTURE

From the theoretical framework of cognitive anthropology based on the work of Charles Frake, this study explored children's classification systems underlying their interactions with illustrated picture storybooks in a classroom context. As a classroom participant-observer, the researcher carried out a classification task where children in a culturally diverse first-grade classroom sorted 15 picture books into piles of books having similar characteristics. It was found that the children classified books by topic, genre, author, culture, emotional response, and physical property of the book. The children's responses were placed in the context of the classroom setting. Some aspects of the children's classification systems were found to be similar to the teacher's way of categorizing books in the classroom library and also her way of classifying books in a book sorting activity.     

The Switch Task for Children: Measuring mental flexibility in young children

Age-related changes in mental flexibility, in the form of task switching, were assessed in 292 children (58–156 months old). Task switching was examined with a new task for young children, the Switch Task for Children (STC). The STC consists of two easy, comparable games and does not require reading skills, which makes it suitable for children younger than 6 years of age. The aims of the present study were: (1) to evaluate the STC; (2) to examine task switching in young children; and (3) to study age-related changes in task switching across childhood. The results indicated that children younger than 6 years are able to switch between two tasks and that general performance increased with age. Young children (58–89 months) displayed a larger global switch cost, that is they made more errors when the tasks were presented randomly compared with a repeated-task baseline, than older children (106–156 months). These findings suggest that the STC is a useful task for detecting task-switching abilities in young children and that the ability to maintain and manipulate two different tasks in working memory, is present, but not yet fully developed, in young children.     

符号数量和非符号数量的空间表征:5岁儿童的SNARC效应和距离效应

对物理刺激的数量信息表征是符号数字表征的前提和基础,据此假设在儿童的SNARC效应发生的时序问题上,非符号数量(如面积)的空间表征早于符号数量(如阿拉伯数字)的空间表征。本研究邀请5岁幼儿完成数字比较和面积比较两类任务,结果发现在数字比较任务中没有出现SNARC效应,但却存在距离效应;在面积比较任务中出现了SNARC效应和距离效应。可以推断,在阿拉伯数字的空间表征出现之前,儿童已经能够对非符号数量信息进行空间表征。     

Effects of two types of activity on the performance of second-, third-, and fourth-grade students on a test of concentration.

The appropriateness of recess in the elementary program continues to be questioned although generally it is believed to be useful by elementary principals despite a dearth of supportive data. This study was a developmental study of the effects of physical activity on concentration. Comparison of passive and directed physical education activities on the concentration of second-, third-, and fourth-grade children was made. The Woodcock-Johnson Test of Concentration showed better performance by the fourth grades and within Grade 4 in favor of the physical activity group. A structured physical activity or a classroom activity immediately prior to a concentration task was not detrimental to children in Grades 2 and 3. Fourth-grade children performed significantly better on a test of concentration after engaging in a physical activity.     

Switching between tasks and responses: a developmental study

Task switching requires the ability to flexibly switch between task rules and responses, and is sensitive to developmental change. We tested the hypothesis that developmental changes in task switch performance are associated with changes in the facilitating or interfering effect of the previously retrieved stimulus-response (S-R) association. Three age groups (7-8-year-olds, 10-12-year-olds and 20-25-year-olds) performed a two-choice reaction time (RT) task in which spatially compatible or incompatible responses were required. The RT costs associated with switching between tasks were larger when responses were repeated than when responses were alternated. Younger children showed a greater cost than adults when switching between tasks but repeating responses. This age difference decreased when the interval between the previous response and the upcoming stimulus increased. Switch costs were larger when switching to the compatible task than to the incompatible task, but this effect did not differ between age groups. These findings suggest that young children build up stronger transient associations between task sets and response sets, which interfere with their ability to switch to currently intended actions. A similar pattern has previously been observed for older adults (Mayr, 2001), suggesting a common contributor to task switching deficits across the life span.     

Voluntary language switching in English–Spanish bilingual children

Although bilingual children frequently switch between languages, the psycholinguistic mechanisms underlying the emerging ability to control language choice are unknown. We examined the mechanisms of voluntary language switching in English–Spanish bilingual children during a picture-naming task under two conditions: (1) single-language naming in English and in Spanish; (2) either-language naming, when the children could use whichever language they wanted. The mechanism of inhibitory control was examined by analysing local switching costs and global mixing costs. The mechanism of lexical accessibility was examined by analysing the properties of the items children chose to name in their non-dominant language. The children exhibited significant switching costs across both languages and asymmetrical mixing costs; they also switched into their non-dominant language most frequently on highly accessible items. These findings suggest that both lexical accessibility and inhibition contribute to language choice during voluntary language switching in children.     

Brain regions activated by endogenous preparatory set shifting as revealed by fMRI

An ongoing controversy concerns whether executive control mechanisms can actively reconfigure the cognitive system in preparation for switching to a new task set. To address this question, we recorded brain activity from 14 healthy participants, using event-related functional magnetic resonance imaging, while they performed a cued attention task. Critically, in any particular trial, the cued task set was either the same as that in the previous trial or switched. As was hypothesized, cue-related, switch-specific preparatory activity was observed in a network of dorsal frontal and parietal brain areas that are typically associated with cognitive control processes. Moreover, the magnitude of switch-specific preparatory activity varied with the number of possible task sets that could be presented in a given trial block. These findings provide compelling support for the existence of top-down, preparatory control processes that enable set switching. Furthermore, they demonstrate that global task structure is a critical determinant of whether switch-specific preparatory activity is observed.     

Grouping of Pupils in Secondary School Classrooms: Possible Links between Pedagogy and Learning

Pupil groupings within classrooms are a constant social pedagogic factor which effect participation and learning. The grouping of pupils provides a dynamic relationship between learning tasks and the classroom context within which learning takes place. This paper explores types of pupil groupings found in secondary school classrooms related to themes of group size and composition, learning task, group interaction and teacher presence. The paper questions how classroom groupings may be related to the circumstances that promote or inhibit school learning. Previous studies concerning classroom grouping in secondary schools have been dominated by ability or attainment level of the child. The approach and review presented in this study advances a new and more extensive understanding of social pedagogic activity within classrooms. Empirically, a novel classroom “mapping” method with follow-up questions for teachers was used to identify within-class grouping characteristics of children aged 12 and 15 years (in school Years 7 and 10), across curriculum subjects (English, mathematics, science and humanities) in secondary schools. Maps were drawn for 250 classrooms and explained by teachers from 47 schools in England. Results identified that a variety of groupings were found in most classes. Use of particular groupings related to phase of lesson and, to some extent, curriculum. The results showed: little pedagogic association with learning task or interaction; teacher presence associated with control of knowledge; and group composition dominated by stereotypical adolescent friendships. Discussion considers the social pedagogic potential of grouping (with regard to relational capital), control of knowledge and social structure of the classroom attributed to the teacher, and patterns of grouping that may be associated with polarisation in the classroom. *Research reported was part of the GRIS (The Nature and Use of Within Class Groupings in Secondary Schools) project funded by the ESRC, grant number R000238172.     

Executive performance on the preschool executive task assessment in children with sickle cell anemia and matched controls

Executive deficits are commonly reported in children with sickle cell anemia. Earlier identification of executive deficits would give more scope for intervention, but this cognitive domain has not been routinely investigated due to a lack of age-appropriate tasks normed for preschool children. In particular, information relating to patient performance on an executive task that reflects an everyday activity in the classroom could provide important insight and practical recommendations for the classroom teacher at this key developmental juncture as they enter the academic domain. The performance of 22 children with sickle cell anemia was compared to 24 matched control children on the Preschool Executive Task Assessment. Findings reveal that children with sickle cell anemia are performing poorer than their matched peers on this multi-step assessment. In particular, children with sickle cell anemia required more structured support to shift focus after a completed step, as reflected by poorer scores in the quantitative Sequencing and Completion domains. They also required more support to stay on task, as seen by poorer ratings in the qualitative Distractibility domain.

Abbreviations:PETA: Preschool Executive Task Assessment; SCA: Sickle Cell Anemia; EF: Executive Functioning.     

Test anxiety and evaluation threat: Children's behavior in the classroom

Children differing in test anxiety level were observed in two art classes, one immediately preceding a classroom examination, the other when no examination was expected. The observational analyses indicated the following: (a) When an examination was expected there were general increases both in children's task orientation and in their concern with other's evaluations, and a decrease in general activity level. It was suggested that future research examine the effects of additional situational variables on children's classroom behaviors, (b) Highly test-anxious children were generally hardworking and inactive. They reacted to examination expectancy with a decrease in task orientation, reduction in communications, and attentional constriction. Less anxious children reacted to examination expectancy by working harder, eliminating task-irrelevant behaviors, and seeking feedback. These results were interpreted as supporting a cognitive theory of test anxiety.This research was supported by Canada Council Grant No. S71-0272.     

Joint task switching

The present study investigates the representation of task-sets in a joint dual-task setting. To this end, a task-switching approach is used. Task switching is associated with a switch cost, which can be decomposed in several markers of task-set coordination. These markers can be used to investigate whether participants represent the co-actor's task-set in a joint dual-task setting. A joint task-switching procedure was used in which two participants performed a distinct task and the participants’ turn to respond could switch or repeat on a trial-by-trial basis. The results indicate that joint task switching also elicits a switch cost. However, this switch cost does not seem to be related to the representation of the co-actor's task-set. It is suggested that the switch cost observed in joint task switching is based on processes of task monitoring, which increase the saliency of task-irrelevant stimulus information.     

Effects of classroom bilingualism on task‐shifting,verbal memory,and word learning in children

We examined the effects of classroom bilingual experience in children on an array of cognitive skills. Monolingual English‐speaking children were compared with children who spoke English as the native language and who had been exposed to Spanish in the context of dual‐immersion schooling for an average of 2 years. The groups were compared on a measure of non‐linguistic task‐shifting; measures of verbal short‐term and working memory; and measures of word learning. The two groups of children did not differ on measures of non‐linguistic task‐shifting and verbal short‐term memory. However, the classroom‐exposure bilingual group outperformed the monolingual group on the measure of verbal working memory and a measure of word learning. Together, these findings indicate that while exposure to a second language in a classroom setting may not be sufficient to engender changes in cognitive control, it can facilitate verbal memory and verbal learning.     

Brain activity related to the ability to inhibit previous task sets: an fMRI study

Switching between tasks requires individuals to inhibit mental representations of the previous task demands and to activate representations of the new demands. To date, investigators have identified only one way to measure task set inhibition??that is, through a backward inhibition (BI) paradigm. In this paradigm, participants take more time to return to a task set that was recently abandoned (e.g., ??A?? in an ABA task sequence) than to a nonrecently abandoned task set (e.g., CBA), and investigators have demonstrated that this time cost reflects time needed to overcome the inhibition of the recently abandoned task set. To date, however, investigators have not been able to use this paradigm, or any other, to isolate brain activity related to task set inhibition. For example, contrasting the brain activity elicited by ABA and CBA trials will not isolate activity related to task set inhibition, because inhibition occurs during the initial switch away from task A (i.e., ABA). Given that there is currently no way to directly isolate the brain activity related to task set inhibition, we decided instead to examine how brain activity during task switching varies in individuals who are better than others at inhibiting the previous task set. We found that participants who were good at inhibiting previous task sets, as measured with the BI paradigm, exhibited more activity in the basal ganglia and supplementary motor area/premotor area when task switching, as measured via functional magnetic resonance imaging. These findings suggest that activity in these regions plays a role in task set inhibition.     

Developmental Changes In Switching Between Mental Task Sets: The Influence Of Verbal Labeling In Childhood

Age-related changes in the use of verbal processes for the efficient switching between tasks were investigated in 5-year-old children (N = 32, M age = 5.9 years) and 9-year-old children (N = 32, M age = 9.4 years). Task switching was assessed by means of a cued switching paradigm to examine two switching components: (a) to maintain and select and (b) to switch between task sets. The aim of this study is to determine (a) developmental changes in both switching components during childhood, (b) whether age-related changes in these components are influenced by verbalizations in terms of “thinking aloud” (Ericsson & Simon, 1993) during task performance, and (c) age changes in the content of the self-verbalizations. Results show an age-related impairment of the 5-year-old group on the level of task-set maintenance and selection. Children mainly verbalized the response labels. However, whereas 5-year-olds more often labeled their perceptions (Zelazo, 1999), 9-year-olds used language to maintain the currently relevant task set. Both age groups relied on the same verbal strategy facilitating task switching, supporting the view that language can be used to plan and guide actions (Luria, 1969).