Behavioral inhibition (BI) is a temperament associated with heightened vigilance and fear of novelty in early childhood, and social reticence and increased risk for anxiety problems later in development. However, not all behaviorally inhibited children develop signs of anxiety. One mechanism that might contribute to the variability in developmental trajectories is the recruitment of cognitive-control resources. The current study measured N2 activation, an ERP (event-related potential) associated with cognitive control, and modeled source-space activation (LORETA; Low Resolution Brain Electromagnetic Tomography) at seven years of age while children performed a go/no-go task. Activation was estimated for the entire cortex and then exported for four regions of interest: ventromedial prefrontal cortex (VMPFC), ventrolateral prefrontal cortex (VLPFC), dorsal anterior cingulate cortex (dorsal ACC), and dorsal lateral prefrontal cortex (DLPFC). BI was measured in early childhood (ages two and three years). Anxiety problems and social reticence were measured at seven years of age to ascertain stability of temperamental style. Results revealed that BI was associated with increased performance accuracy, longer reaction times, greater (more negative) N2 activation, and higher estimated dorsal ACC and DLPFC activation. Furthermore, early BI was only associated with social reticence at age 7 at higher (more negative) levels of N2 activation or higher estimated dorsal ACC or DLPFC activation. Results are discussed in the context of overcontrolled behavior contributing to social reticence and signs of anxiety in middle childhood.
Behavioral inhibition; cognitive control; no-go N2; social reticence; dorsal anterior cingulate cortex; dorsolateral prefrontal cortex; children
Associations between early deprivation and memory functioning were examined in 9- to 11-year-old children. Children who had experienced prolonged institutional care prior to adoption were compared to children who were adopted early from foster care and children reared in birth families. Measures included the Paired Associates Learning task from the Cambridge Neuropsychological Test and Automated Battery (CANTAB) and a continuous recognition memory task during which ERPs were also recorded. Children who experienced prolonged institutionalization showed deficits in both behavioral memory measures as well as an attenuated P300 parietal memory effect. Results implicate memory function as one of the domains that may be negatively influenced by early deprivation in the form of institutional care.
neurodevelopment; memory functioning; ERP; post-institutionalized children; international adoption
Individuals with autism spectrum disorders (ASD) have difficulty understanding other minds (Theory of Mind; ToM), with atypical processing evident at both behavioural and neural levels. Individuals with conduct problems and high levels of callous-unemotional (CU) traits (CP/HCU) exhibit reduced responsiveness to others' emotions and difficulties interacting with others, but nonetheless perform normally in experimental tests of ToM. The present study aimed to examine the neural underpinnings of ToM in children (aged 10–16) with ASD (N = 16), CP/HCU (N = 16) and typically developing (TD) controls (N = 16) using a non-verbal cartoon vignette task. Whilst individuals with ASD were predicted to show reduced fMRI responses across regions involved in ToM processing, CP/HCU individuals were predicted to show no differences compared with TD controls. The analyses indicated that neural responses did not differ between TD and CP/HCU groups during ToM. TD and CP/HCU children exhibited significantly greater medial prefrontal cortex responses during ToM than did the ASD group. Within the ASD group, responses in medial prefrontal cortex and right temporoparietal junction (TPJ) correlated with symptom severity as measured by the Autism Diagnostic Observation Schedule (ADOS). Findings suggest that although both ASD and CP/HCU are characterized by social difficulties, only children with ASD display atypical neural processing associated with ToM.
The ability to interpret and predict the actions of others is crucial to social interaction and to social, cognitive, and linguistic development. The current study provided a strong test of this predictive ability by assessing (1) whether infants are capable of prospectively processing actions that fail to achieve their intended outcome, and (2) how infants respond to events in which their initial predictions are not confirmed. Using eye tracking, 8-month-olds, 10-month-olds, and adults watched an actor repeatedly reach over a barrier to either successfully or unsuccessfully retrieve a ball. Ten-month-olds and adults produced anticipatory looks to the ball, even when the action was unsuccessful and the actor never achieved his goal. Moreover, they revised their initial predictions in response to accumulating evidence of the actor’s failure. Eight-month-olds showed anticipatory looking only after seeing the actor successfully grasp and retrieve the ball. Results support a flexible, prospective social information processing ability that emerges during the first year of life.
Research suggests that the presence of peers influences adolescent risk-taking by increasing the perceived reward value of risky decisions. While prior work has involved observation of participants by their friends, the current study examined whether observation by an anonymous peer could elicit similarly increased reward sensitivity. Late adolescent participants completed a delay discounting task either alone or under the belief that performance was being observed from a neighboring room by an unknown viewer of the same gender and age. Even in this limited social context, participants demonstrated a significantly increased preference for smaller, immediate rewards when they believed that they were being watched. This outcome challenges several intuitive accounts of the peer effect on adolescent risk taking, and indicates that the peer influence on reward sensitivity during late adolescence is not dependent on familiarity with the observer. The findings have both theoretical and practical implications for our understanding of social influences on adolescents’ risky behavior.
One hallmark of adolescent risk taking is that it typically occurs when adolescents are with peers. It has been hypothesized that the presence of peers primes a reward-sensitive motivational state that overwhelms adolescents’ immature capacity for inhibitory control. We examined this hypothesis using a rodent model. A sample of mice were raised in same-sex triads and were tested for alcohol consumption either as juveniles or as adults, with half in each age group tested alone and half tested with their cagemates. The presence of “peers” increased alcohol consumption among adolescent mice, but not adults. The peer effect on human adolescent reward-seeking may reflect a hard-wired, evolutionarily conserved process through which the presence of agemates increases individuals’ sensitivity to potential rewards in their immediate environment.
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 two 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.
bilingualism; dual-immersion; cognitive control; verbal learning
Do words cue children’s visual attention, and if so, what are the relevant mechanisms? Across four experiments, 3-year-old children (N = 163) were tested in visual search tasks in which targets were cued with only a visual preview versus a visual preview and a spoken name. The experiments were designed to determine whether labels facilitated search times and to examine one route through which labels could have their effect: By influencing the visual working memory representation of the target. The targets and distractors were pictures of instances of basic-level known categories and the labels were the common name for the target category. We predicted that the label would enhance the visual working memory representation of the target object, guiding attention to objects that better matched the target representation. Experiments 1 and 2 used conjunctive search tasks, and Experiment 3 varied shape discriminability between targets and distractors. Experiment 4 compared the effects of labels to repeated presentations of the visual target, which should also influence the working memory representation of the target. The overall pattern fits contemporary theories of how the contents of visual working memory interact with visual search and attention, and shows that even in very young children heard words affect the processing of visual information.
According to some views of cognitive growth, the development of working memory capacity can account for increases in the complexity of cognition. It has been difficult to ascertain, though, that there actually is developmental growth in capacity that cannot be attributed to other developing factors. Here we assess the role of item familiarity. We document developmental increases in working memory for visual arrays of English letters versus unfamiliar characters. Although letter knowledge played a special role in development between the ages of 6 to 8 years, children with adequate letter knowledge showed practically the same developmental growth in normalized functions for letters and unfamiliar characters. The results contribute to a growing body of evidence that the developmental improvement in working memory does not wholly stem from supporting processes such as encoding, mnemonic strategies, and knowledge.
In this 8-year longitudinal study, we traced the vocabulary growth of Chinese children, explored potential precursors of vocabulary knowledge, and investigated how vocabulary growth predicted future reading skills. Two hundred sixty-four (264) native Chinese children from Beijing were measured on a variety of reading and language tasks over 8 years. Between the ages of 4 to 10 years, they were administered tasks of vocabulary and related cognitive skills. At age 11, comprehensive reading skills, including character recognition, reading fluency, and reading comprehension were examined. Individual differences in vocabulary developmental profiles were estimated using the intercept-slope cluster method. Vocabulary development was then examined in relation to later reading outcomes. Three subgroups of lexical growth were classified, namely high-high (with a large initial vocabulary size and a fast growth rate), low-high (with a small initial vocabulary size and a fast growth rate) and low-low (with a small initial vocabulary size and a slow growth rate) groups. Low-high and low-low groups were distinguishable mostly through phonological skills, morphological skills and other reading-related cognitive skills. Childhood vocabulary development (using intercept and slope) explained subsequent reading skills. Findings suggest that language-related and reading-related cognitive skills differ among groups with different developmental trajectories of vocabulary, and the initial size and growth rate of vocabulary may be two predictors for later reading development.
vocabulary development; growth rate; initial size; reading
We examine developmental interactions between context, exploration, and word learning. Infants show an understanding of how nonsolid substances are categorized that does not reliably transfer to learning how these categories are named in laboratory tasks. We argue what infants learn about naming nonsolid substances is contextually bound—most nonsolids toddlers are familiar with are foods and thus, typically experienced when sitting in a highchair. We asked whether 16-month-old children’s naming of nonsolids would improve if they were tested in that typical context. Children tested in the highchair demonstrated better understanding of how nonsolids are named. Furthermore, context-based differences in exploration drove differences in the properties attended to in real-time. We discuss what implications this context-dependency has for understanding the development of an ontological distinction between solids and nonsolids.“Together, these results demonstrate a developmental cascade between context, exploration, and word learning.
When visual information is available, human adults, but not children, have been shown to reduce sensory uncertainty by taking a weighted average of sensory cues. In the absence of reliable visual information (e.g. extremely dark environment, visual disorders), the use of other information is vital. Here we ask how humans combine haptic and auditory information from childhood. In the first experiment, adults and children aged 5 to 11 years judged the relative sizes of two objects in auditory, haptic, and non-conflicting bimodal conditions. In Experiment 2, different groups of adults and children were tested in non-conflicting and conflicting bimodal conditions. In Experiment 1, adults reduced sensory uncertainty by integrating the cues optimally, while children did not. In Experiment 2, adults and children used similar weighting strategies to solve audio–haptic conflict. These results suggest that, in the absence of visual information, optimal integration of cues for discrimination of object size develops late in childhood.
How does the brain’s response to speech change over the first months of life? Although behavioral findings indicate that neonates’ listening biases are sharpened over the first months of life, with a species-specific preference for speech emerging by 3 months, the neural substrates underlying this developmental change are unknown. We examined neural responses to speech compared with biological non-speech sounds in 1- to 4-month-old infants using fMRI. Infants heard speech and biological non-speech sounds, including heterospecific vocalizations and human non-speech. We observed a left-lateralized response in temporal cortex for speech compared to biological non-speech sounds, indicating that this region is highly selective for speech by the first month of life. Specifically, this brain region becomes increasingly selective for speech over the next 3 months as neural substrates become less responsive to non-speech sounds. These results reveal specific changes in neural responses during a developmental period characterized by rapid behavioral changes.
Children with low working memory typically make poor educational progress, and it has been speculated that difficulties in meeting the heavy working memory demands of the classroom may be a contributory factor. Intensive working memory training has been shown to boost performance on untrained memory tasks in a variety of populations. This first randomized controlled trial with low working memory children investigated whether the benefits of training extend beyond standard working memory tasks to other more complex activities typical of the classroom in which working memory plays a role, as well as to other cognitive skills and developing academic abilities. Children aged 7–9 years received either adaptive working memory training, non-adaptive working memory training with low memory loads, or no training. Adaptive training was associated with selective improvements in multiple untrained tests of working memory, with no evidence of changes in classroom analogues of activities that tax working memory, or any other cognitive assessments. Gains in verbal working memory were sustained one year after training. Thus the benefits of working memory training delivered in this way may not extend beyond structured working memory tasks.
Despite implications that stranger fear is an important aspect of developing behavioral inhibition, a known risk factor for anxiety, normative and atypical developmental trajectories of stranger fear across infancy and toddlerhood remain understudied. We used a large, longitudinal data set (N = 1285) including multi-trait, multi-method assessments of temperament to examine the normative course of development for stranger fear and to explore the possibility that individual differences exist in trajectories of stranger fear development between 6 and 36 months of age. A latent class growth analysis suggested four different trajectories of stranger fear during this period. Stable, high levels of stranger fear over time were associated with poorer RSA suppression at six months of age. Rates of concordance in trajectory-based class membership for identical (monozygotic) and fraternal (dizygotic) twins, along with associations between atypical stranger fear development and greater anxiety-related maternal characteristics, suggested that individual differences in developmental trajectories of stranger fear may be heritable. Importantly, trajectories of stranger fear during infancy and toddlerhood were linked to individual differences in behavioral inhibition, with chronically high levels of stranger fear and sharp increases in stranger fear over time related to greater levels of inhibition than other developmental trajectories.
Stranger Fear; Infancy; RSA; Maternal Anxiety; Development
Impulsivity is a salient individual difference in children with well-established predictive validity for life outcomes. The current investigation proposes that impulsive behaviors vary systematically by domain. In a series of studies with ethnically and socioeconomically diverse samples of middle school students, we find that schoolwork-related and interpersonal-related impulsivity, as observed by teachers, parents, and the students themselves, are distinct, moderately correlated behavioral tendencies. Each demonstrates differentiated relationships with dimensions of childhood temperament, Big Five personality factors, and outcomes, such as sociometric popularity, report card grades, and classroom conduct. Implications for theoretical conceptions of impulsivity as well as for practical applications (e.g., domain-specific interventions) are discussed.
impulsivity; self-control; domain-specificity; academic achievement
The present study examined the hypothesis that inhibitory visual selection mechanisms play a vital role in memory by limiting distractor interference during item encoding. In Experiment 1a we used a modified spatial cueing task in which 9-month-old infants encoded multiple category exemplars in the contexts of an attention orienting mechanism involving suppression (i.e., inhibition of return, IOR) versus one that does not (i.e., facilitation). At test, infants in the IOR condition showed both item specific learning as well as abstraction of broader category information. In contrast, infants in the facilitation condition did not discriminate across novel and familiar test items. Experiment 1b confirmed that the learning observed in the IOR condition was specific to spatial cueing of attention and was not due to timing differences across the IOR and facilitation conditions. In Experiment 2, we replicated the results of Experiment 1, using a within-subjects design to explicitly examine learning and memory encoding in the context of concurrent suppression. These data show that developing inhibitory selective attention enhances efficacy of memory encoding for subsequent retrieval. Furthermore, these results highlight the importance of considering interactions between developing attention and memory systems.
selective attention; memory; encoding; spatial cueing
The current study examines the processing of upright and inverted faces
in 3-year-old children (n = 35). Event-related potentials
(ERPs) were recorded during a passive-looking paradigm including adult and
newborn face stimuli. We observed three face-sensitive components, the P1, the
N170 and the P400. Inverted faces elicited shorter P1 latency and larger P400
amplitude. P1 and N170 amplitudes were larger for adult faces. To examine the
role of experience in the development of face processing, the processing of
adult and newborn faces was compared for children with a younger sibling
(n = 23) and children without a younger sibling
(n = 12). Age of sibling at test correlated negatively with
P1 amplitude for adult and newborn faces. This may indicate more efficient
processing of different face ages in children with a younger sibling and
potentially reflects a more flexible face representation.
face processing; children; experience; event-related potentials
The structure of the human brain changes in several ways throughout childhood and adolescence. Perhaps the most salient of these changes is the strengthening of white matter tracts that enable distal brain regions to communicate with one another more quickly and efficiently. Here, we sought to understand whether and how white matter changes contribute to improved reasoning ability over development. In particular, we sought to understand whether previously reported relationships between white matter microstructure and reasoning are mediated by processing speed. To this end, we analyzed diffusion tensor imaging data as well as data from standard psychometric tests of cognitive abilities from 103 individuals between the ages of 6 and 18. We used structural equation modeling to investigate the network of relationships between brain and behavior variables. Our analyses provide support for the hypothesis that white matter maturation (as indexed either by microstructural organization or volume) supports improved processing speed, which, in turn, supports improved reasoning ability.
Research over the past 20 years has revealed that even very young infants possess expectations about physical events, and that these expectations undergo significant developments during the first year of life. In this article, I first review some of this research, focusing on infants’ expectations about occlusion, containment, and covering events, all of which involve hidden objects. Next, I present an account of infants’ physical reasoning that integrates these various findings, and describe new experiments that test predictions from this account. Finally, because all of the research I discuss uses the violation-of-expectation method, I address recent concerns about this method and summarize new findings that help alleviate these concerns.
Previous research shows that sensory and motor systems interact during perception, but how these connections among systems are created during development is unknown. The current work exposes young children to novel ‘verbs’ and objects through either (a) actively exploring the objects or (b) by seeing an experimenter interact with the objects. Results demonstrate that the motor system is recruited during auditory perception only after learning involved self-generated interactions with objects. Action observation itself led to above-baseline activation in one motor region during visual perception, but was still significantly less active than after self-generated action. Therefore, in the developing brain, associations are built upon real-world interactions of body and environment, leading to sensori-motor representations of both objects and words.
Since Broca's studies on language processing, cortical functional specialization has been considered to be integral to efficient neural processing. A fundamental question in cognitive neuroscience concerns the type of learning that is required for functional specialization to develop. To address this issue with respect to the development of neural specialization for letters, we used functional magnetic resonance imaging (fMRI) to compare brain activation patterns in pre-school children before and after different letter-learning conditions: a sensori-motor group practised printing letters during the learning phase, while the control group practised visual recognition. Results demonstrated an overall left-hemisphere bias for processing letters in these pre-literate participants, but, more interestingly, showed enhanced blood oxygen-level-dependent activation in the visual association cortex during letter perception only after sensori-motor (printing) learning. It is concluded that sensori-motor experience augments processing in the visual system of pre-school children. The change of activation in these neural circuits provides important evidence that ‘learning-by-doing’ can lay the foundation for, and potentially strengthen, the neural systems used for visual letter recognition.
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.
The association of parental social status with multiple health and achievement indicators in adulthood has driven researchers to attempt to identify mechanisms by which social experience in childhood could shift developmental trajectories. Some accounts for observed linkages between parental social status in childhood and health have hypothesized that early stress exposure could result in chronic disruptions in hypothalamic-pituitary-adrenal (HPA) axis activation, and that this activation could lead to long term changes. A robust literature in adult animals has demonstrated that chronic HPA axis activation leads to changes in hippocampal structure and function. In the current study, consistent with studies in animals, we observe an association between both maternal self-rated social status and hippocampal activation in children and between maternal self-rated social status and salivary cortisol in children.