Imitation and representational development in young children with Down syndrome

Competence in object search and pretend play are argued to reflect young children's representational abilities and appear delayed in children with Down syndrome relative to social and imitative skills. This paper explores the effects on object search and play of this social strength in children with Down syndrome. Three experiments compared performance on traditional tasks with modified tasks designed to assess the role of imitation in object search and pretend play. Children with Down syndrome, relative to typically‐developing children, were able and willing to imitate hiding actions when no object was hidden (Experiment 1). When imitation was prevented in object search, children with Down syndrome searched less effectively than typically‐developing children (Experiment 2). In play, children with Down syndrome expressed more willingness to imitate a counter‐functional action, modelled by the experimenter, despite apparent competence in spontaneous functional play (Experiment 3). These findings indicate that object search and play behaviours of children with Down syndrome rely more heavily on imitation than is the case for typically‐developing children. The implications for the development of children with Down syndrome and models of representational development are discussed.     

Processing of compound visual stimuli by children with autism and Asperger syndrome

A typical modes of visual processing are common in individuals with autism. In particular, and unlike typically developing children, children with autism tend to process the parts of a complex object as a priority, rather than attending to the object as a whole. This bias for local processing is likely to be due to difficulties in assembling subparts into a coherent whole, as proposed by Frith ( 10 1989) using the term “weak central coherence” or WCC. This study was aimed to better characterize the processing of complex visual stimuli by children with autism. Thirteen children with autistic spectrum disorders were individually paired with children of two control groups, one matched on verbal mental age (VMA) and one matched on chronological age (CA). Participants from the three groups were tested in two tasks. The first task involved hierarchical global/local stimuli, inspired by Navon ( 30 1977). The second task employed compound face‐like or geometrical stimuli. This task emphasized the processing of configural properties of the stimuli (i.e., spatial relationships). Children from the three groups showed a perceptual bias favouring the global dimension of the stimuli in the first task. By contrast, children with autism were deficient compared to normal children for the processing of the configural dimensions of the stimuli in the second task. These results suggest that visual cognition of children with autism is characterized by a dissociation between global and configural processing, with global processing being preserved and configural processing being altered in these children, therefore delineating the extents and limits of the WCC theory (Frith, 10 1989).     

The development of face and location processing: an fMRI study

Although a few developmental fMRI studies have shed some light on the neurological development of either object or spatial processing we still know very little about the development of the ‘what’ and ‘where’ processing systems. The present study is the first to address this issue by comparing, concurrently and within the same behavioral paradigm, patterns of functional activation for face processing and location processing in 12 children (10–12 years old) and 16 adults. For both tasks this study found a developmental shift from a more distributed pattern of activation in children to a more focused pattern of activation in adults. Furthermore, the type of developmental redistribution of activation in children varied depending on the task. The present findings have important implications for theories of visuospatial development. They suggest that the neural systems involved in face and location processing may undergo development and fine‐tuning well into late childhood.     

Guessing versus choosing – and seeing versus believing – in false belief tasks

Three‐ and 4‐year‐old children were tested using videos of puppets in various versions of a theory of mind change‐of‐location situation, in order to answer several questions about what children are doing when they pass false belief tests. To investigate whether children were guessing or confidently choosing their answer to the test question, a condition in which children were forced to guess was also included, and measures of uncertainty were compared across conditions. To investigate whether children were using simpler strategies than an understanding of false belief to pass the test, we teased apart the seeing‐knowing confound in the traditional change‐of‐location task. We also investigated relations between children's performance on true and false belief tests. Results indicated that children appeared to be deliberately choosing, not guessing, in the false belief tasks. Children performed just as well whether the protagonist gained information about the object visually or verbally, indicating that children were not using a simple rule based on seeing to predict the protagonist's behaviour. A true belief condition was significantly easier for children than a false belief condition as long as it was of low processing demands. Children's success rate on the different versions of the standard false belief task was influenced by factors such as processing demands of the stories and the child's verbal abilities.     

A constructivist connectionist model of transitions on false-belief tasks

How do children come to understand that others have mental representations, e.g., of an object’s location? Preschoolers go through two transitions on verbal false-belief tasks, in which they have to predict where an agent will search for an object that was moved in her absence. First, while three-and-a-half-year-olds usually fail at approach tasks, in which the agent wants to find the object, children just under four succeed. Second, only after four do children succeed at tasks in which the agent wants to avoid the object. We present a constructivist connectionist model that autonomously reproduces the two transitions and suggests that the transitions are due to increases in general processing abilities enabling children to (1) overcome a default true-belief attribution by distinguishing false- from true-belief situations, and to (2) predict search in avoidance situations, where there is often more than one correct, empty search location. Constructivist connectionist models are rigorous, flexible and powerful tools that can be analyzed before and after transitions to uncover novel and emergent mechanisms of cognitive development.     

Attention problems and executive functions in children with spina bifida and hydrocephalus.

This study addressed the incidence of Attention-Deficit/Hyperactivity Disorder (ADHD) subtypes in children with spina bifida meningomyelocele and shunted hydrocephalus (SBH) as well as differences in executive functions among these subtypes. Parent rating scales revealed that 31% of the group with SBH could be identified with AD/HD, mostly the Inattentive type (23%). The group with SBH differed from normal controls on cognitive measures of executive functions, but subtype differences were not significant. Multivariate tests showed that children with SBH were rated with greater difficulties on the Behavior Rating Inventory of Executive Function (BRIEF) compared to controls; those with SBH and any subtype of ADHD differed from those with SBH and no ADHD; and those with ADHD (Combined Type) differed significantly from those with ADHD (Predominantly Inattentive Type). Subtype differences on univariate tests in the latter comparison were significant on the BRIEF Inhibit scale, showing more disinhibition in those with SBH and ADHD (Combined Type), but no significant differences were apparent on the BRIEF Sustain, Shift, and Initiate scales. The results show that the incidence of ADHD in children with SBH exceeds the population rate, is represented by problems with inattention rather than with impulsivity and hyperactivity; and that as with non-brain injured individuals, subtype differences in cognitive function remain to more clearly delineated.     

Attention Problems and Executive Functions in Children With Spina Bifida and Hydrocephalus

This study addressed the incidence of Attention-Deficit/Hyperactivity Disorder (ADHD) subtypes in children with spina bifida meningomyelocele and shunted hydrocephalus (SBH) as well as differences in executive functions among these subtypes. Parent rating scales revealed that 31% of the group with SBH could be identified with AD/HD, mostly the Inattentive type (23%). The group with SBH differed from normal controls on cognitive measures of executive functions, but subtype differences were not significant. Multivariate tests showed that children with SBH were rated with greater difficulties on the Behavior Rating Inventory of Executive Function (BRIEF) compared to controls; those with SBH and any subtype of ADHD differed from those with SBH and no ADHD; and those with ADHD (Combined Type) differed significantly from those with ADHD (Predominantly Inattentive Type). Subtype differences on univariate tests in the latter comparison were significant on the BRIEF Inhibit scale, showing more disinhibition in those with SBH and ADHD (Combined Type), but no significant differences were apparent on the BRIEF Sustain, Shift, and Initiate scales. The results show that the incidence of ADHD in children with SBH exceeds the population rate, is represented by problems with inattention rather than with impulsivity and hyperactivity; and that as with non-brain injured individuals, subtype differences in cognitive function remain to more clearly delineated.     

Object‐spatial imagery: a new self‐report imagery questionnaire

A new instrument, the Object‐Spatial Imagery Questionnaire (OSIQ), was designed to assess individual differences in visual imagery preferences and experiences. The OSIQ consists of two scales: an object imagery scale that assesses preferences for representing and processing colourful, pictorial, and high‐resolution images of individual objects and a spatial imagery scale that assesses preferences for representing and processing schematic images, spatial relations amongst objects, and spatial transformations. Across a series of studies, the object imagery scale was significantly correlated with the performance on object imagery tasks; the spatial imagery scale was significantly correlated with the performance on spatial imagery tasks; but neither correlated with measures of intelligence. Additionally, compared to visual artists and humanities professionals, scientists reported higher spatial imagery ratings; however, compared to scientists and humanities professionals, visual artists reported higher object imagery ratings. Thus, the results from the studies supported the predictive, discriminant, and ecological validity of the OSIQ. Copyright © 2006 John Wiley & Sons, Ltd.     

It's about time: revisiting temporal processing deficits in dyslexia

Temporal processing in French children with dyslexia was evaluated in three tasks: a word identification task requiring implicit temporal processing, and two explicit temporal bisection tasks, one in the auditory and one in the visual modality. Normally developing children matched on chronological age and reading level served as a control group. Children with dyslexia exhibited robust deficits in temporal tasks whether they were explicit or implicit and whether they involved the auditory or the visual modality. First, they presented larger perceptual variability when performing temporal tasks, whereas they showed no such difficulties when performing the same task on a non‐temporal dimension (intensity). This dissociation suggests that their difficulties were specific to temporal processing and could not be attributed to lapses of attention, reduced alertness, faulty anchoring, or overall noisy processing. In the framework of cognitive models of time perception, these data point to a dysfunction of the ‘internal clock’ of dyslexic children. These results are broadly compatible with the recent temporal sampling theory of dyslexia.     

Preschool children’s interpretation of object‐initial sentences: Neural correlates of their behavioral performance

The acquisition of the function of case‐marking is a key step in the development of sentence processing for German‐speaking children since case‐marking reveals the relations between sentential arguments. In this study, we investigated the development of the processing of case‐marking and argument structures in children at 3, 4;6 and 6 years of age, as well as its processing in adults. Using EEG, we measured event‐related potentials (ERPs) in response to object‐initial compared to subject‐initial German sentences including transitive verbs and case‐marked noun phrases referring to animate arguments. We also tested children’s behavioral competence in a sentence‐picture matching task. Word order and case‐marking were manipulated in German main clauses. Adults’ behavioral performance was close to perfect and their ERPs revealed a negativity for the processing of the topicalized accusative marked noun phrase (NP1) and no effect for the second NP (NP2) in the object‐initial structure. Children’s behavioral data showed a significant above‐chance outcome in the subject‐initial condition for all age groups, but not for the object‐initial condition. In contrast to adults, the ERPs of 3‐year‐olds showed a positivity at NP1, indicating difficulties in processing the non‐canonical object‐initial structures. Children at the age of 4;6 did not differ in the processing patterns of object‐initial vs. subject‐initial sentences at NP1 but showed a slight positivity at NP2. This positivity at NP2, which implies syntactic integration difficulties, is more pronounced in 6‐year‐olds but is absent in adults. At NP1, however, 6‐year‐olds show the same negativity as adults. In sum, the behavioral and electrophysiological findings demonstrate that children in each age group use different strategies, which are indicative of their developmental stage. While 3‐year‐olds merely detect differences in the two sentence structures without being able to use this information for sentence comprehension, 4;6‐year‐olds proceed to use mainly a word‐order strategy, processing NP1 in both conditions in the same manner, which leads to processing difficulties upon detecting case‐marking cues at NP2. At the age of 6, children are able to use case‐marking cues for comprehension but still show enhanced effort for correct thematic‐role assignment.     

The animate–inanimate distinction in preschool children

This study examined the development of the animate–inanimate (A–I) distinction in relation to other taxonomic categories in early childhood. Four‐ and 5‐year‐old children were administered two tasks measuring knowledge of taxonomic categories at various levels of inclusiveness. Across both matching‐to‐sample and object sorting tasks, the same pattern of categorization development was observed. Mastery of basic‐ and superordinate‐level categories was demonstrated by 4 years of age. Although 5‐year‐old children performed above chance on A–I level categories, their abilities were not as mature as those of adults. Results of this study support and extend previous studies investigating the development of children's understanding of naïve biology during the preschool years.     

The development of mental models for auditory events: Relational complexity and discrimination of pitch and duration

This experiment investigated relational complexity and relational shift in judgments of auditory patterns. Pitch and duration values were used to construct two‐note perceptually similar sequences (unary relations) and four‐note relationally similar sequences (binary relations). It was hypothesized that 5‐, 8‐ and 11‐year‐old children would perform unary level pitch and duration discrimination tasks accurately. Relational shift predicted a poorer performance of the younger age groups on binary relation tasks; relational primacy predicted no effect of age. Accuracy was operationalized as a discrimination index (DI: hit rate minus false alarm rate). Results supported relational shift: DI for all age groups exceeded chance on unary and binary relation tasks, with significantly poorer performance by all age groups on binary relation tasks. The 5‐years age group showed evidence of perceptual similarity. Relational complexity of auditory dimensions and tasks, and manipulation of domain specific musical knowledge in evaluating theories of relational processing, are discussed.     

Neuromotor speech deficits in children and adults with spina bifida and hydrocephalus

Acquired cerebellar lesions are associated with motor speech deficits. Spina bifida with hydrocephalus (SBH) is a neurodevelopmental disorder that involves significant dysmorphology of the cerebellum. Videotaped narratives produced by 40 children and adults with SBH and their 40 age-matched controls were coded for three motor speech deficits: dysfluency, ataxic dysarthria (articulatory inaccuracy, prosodic excess, and phonatory-prosodic insufficiency) (Brown, Darley, & Aronson, 1970; Darley, Aronson, & Brown, 1969a), and speech rate. Individuals with SBH had more motor speech deficits than controls. Dysfluency was related to an interaction between chronological age and SBH. Speech rate was related independently to chronological age and SBH. Ataxic dysarthria was related to the biology of SBH, and was associated with both physical phenotype (level of spinal cord lesion) and medical history (number of shunt revisions). The data show that developmental as well as acquired lesions of the cerebellum disrupt motor speech, and add to the developmental role of the cerebellum in the automatization of motor skills, including speech.     

The role of competition in word learning via referent selection

Previous research suggests that competition among the objects present during referent selection influences young children’s ability to learn words in fast mapping tasks. The present study systematically explored this issue with 30‐month‐old children. Children first received referent selection trials with a target object and either two, three or four competitor objects. Then, after a short delay, children were tested on their ability to retain the newly fast‐mapped names. Overall, the number of competitors did not affect children’s ability to form the initial name–object mappings. However, only children who encountered few competitors during referent selection demonstrated significant levels of retention. Results and implications are discussed in terms of the role of competition in studies of children’s fast mapping. The relationship between referent selection and full word learning is also discussed.     

Developmental profiles for multiple object tracking and spatial memory: typically developing preschoolers and people with Williams syndrome

The ability to track moving objects, a crucial skill for mature performance on everyday spatial tasks, has been hypothesized to require a specialized mechanism that may be available in infancy (i.e. indexes). Consistent with the idea of specialization, our previous work showed that object tracking was more impaired than a matched spatial memory task in individuals with Williams syndrome (WS), a genetic disorder characterized by severe visuo‐spatial impairment. We now ask whether this unusual pattern of performance is a reflection of general immaturity or of true abnormality, possibly reflecting the atypical brain development in WS. To examine these two possibilities, we tested typically developing 3‐ and 4‐year‐olds and people with WS on multiple object tracking (MOT) and memory for static spatial location. The maximum number of objects that could be correctly tracked or remembered (estimated from the k‐statistic) showed similar developmental profiles in typically developing 3‐ and 4‐year‐old children, but the WS profile differed from either age group. People with WS could track more objects than 3‐year‐olds, and the same number as 4‐year‐olds, but they could remember the locations of more static objects than both 3‐ and 4‐year‐olds. Combining these data with those from our previous studies, we found that typically developing children show increases in the number of objects they can track or remember between the ages of 3 and 6, and these increases grow in parallel across the two tasks. In contrast, object tracking in older children and adults with WS remains at the level of 4‐year‐olds, whereas the ability to remember multiple locations of static objects develops further. As a whole, the evidence suggests that MOT and memory for static location develop in tandem typically, but not in WS. Atypical development of the parietal lobe in people with WS could play a causal role in the abnormal, uneven pattern of performance in WS. This interpretation is consistent with the idea that multiple object tracking engages different mechanisms from those involved in memory for static object location, and that the former can be particularly disrupted by atypical development.     

Deficits in volitional oculomotor control align with language status in autism spectrum disorders

Eye‐tracking paradigms are increasingly used to investigate higher‐level social and cognitive processing in autism spectrum disorder (ASD). However, the integrity of the oculomotor system within ASD is unclear, with contradictory reports of aberrant eye‐movements on basic oculomotor tasks. The purpose of the current study was to determine whether reducing population heterogeneity and distinguishing neurocognitive phenotypes can clarify discrepancies in oculomotor behaviour evident in previous reports. Reflexive and volitional eye‐movement control was assessed in 73 children aged 8–14 years from four distinct groups: Autism Language Normal (ALN), Autism Language Impaired (ALI), non‐autistic Language Impaired (LI) and Typically Developing (TD). Eye‐movement control was measured using pro‐ and antisaccade tasks and a novel ‘search distracter’ task to measure distractibility. Reflexive eye‐movements were equivalent across groups, but deficits in volitional eye‐movement control were found that aligned with language status, and were not specific to ASD. More than 80% of ALI and LI children presented error rates at least 1.5 SDs below the TD mean in an antisaccade task. In the search distracter task, 35.29% of ALI children and 43.75% of LI children had error rates greater than 1.5 SDs compared with 17.64% of ALN children. A significant proportion of children with neurodevelopmental disorders involving language function have pronounced difficulties suppressing reflexive saccades and maintaining fixations in the presence of competing stimuli. We extend the putative link between ALI and LI populations to non‐language tasks, and highlight the need to account for co‐morbidity in understanding the ontogenesis of ASD.     

The comparative judgements of generally and specifically gifted children

Different groups of children were compared on sentence verification tasks. The children were either academically, musically or artistically gifted, and there were two forms of the task. In one, a picture was followed by a sentence, and in another, one sentence was followed by another. Subjects had to decide as quickly as possible whether or not the second proposition logically confirmed the first. In the picture-sentence condition results from all groups could be fitted to the constituent comparison model for sentence verification proposed by Carpenter and Just (1975). For the sentence-sentence condition, however, the observed results diverged from those predicted by the model. The results are explained in terms of different degrees of linguistic processing capacities of the subjects, and they demonstrate the importance which verbal-logical congruence has for children. Artistically able children had difficulties in processing subject/object incongruence in sentence pairs whereas musically able children had more problems in processing above/below incongruence.     

Cross‐linguistic interactions influence reading development in bilinguals: a comparison between early balanced French‐Basque and Spanish‐Basque bilingual children

This study investigates whether orthographic consistency and transparency of languages have an impact on the development of reading strategies and reading sub‐skills (i.e. phonemic awareness and visual attention span) in bilingual children. We evaluated 21 French (opaque)‐Basque (transparent) bilingual children and 21 Spanish (transparent)‐Basque (transparent) bilingual children at Grade 2, and 16 additional children of each group at Grade 5. All of them were assessed in their common language (i.e. Basque) on tasks measuring word and pseudoword reading, phonemic awareness and visual attention span skills. The Spanish speaking groups showed better Basque pseudoword reading and better phonemic awareness abilities than their French speaking peers, but only in the most difficult conditions of the tasks. However, on the visual attention span task, the French‐Basque bilinguals showed the most efficient visual processing strategies to perform the task. Therefore, learning to read in an additional language affected differently Basque literacy skills, depending on whether this additional orthography was opaque (e.g. French) or transparent (e.g. Spanish). Moreover, we showed that the most noteworthy effects of Spanish and French orthographic transparency on Basque performance were related to the size of the phonological and visual grain used to perform the tasks.     

数学学习困难儿童的编码加工特点:基于PASS理论的研究

同时加工和继时加工是PASS模型中的两类编码加工,二者在数学学习中发挥重要作用。使用基于PASS理论的认知评估系统（DN：CAS）单纯型数学困难、混合型数学困难和正常小学生进行两类编码加工的测评,比较研究发现,两类困难学生的两类编码加工水平均显著低于正常儿童,两类困难学生间的同时加工差异不显著,而混合型困难学生的继时加工水平显著低于单纯型困难学生。较低的同时加工水平似乎是两类数学困难的共同特征,继时加工水平的差异则似可作为单纯型与混合型困难的区分指标之一。