Infant attention and early childhood executive function

Do low birth weight infants not see eyes? Face recognition in infancy

BACKGROUND

Progress in neonatal medicine has dramatically improved the survival rate of preterm births, but the evidence suggests that these low-birth weight infants (LBWIs) go on to develop pervasive development disorders and attention deficit hyperactivity disorder (ADHD) at greater rates than the general population. Children with neurodevelopmental disorders are known to suffer from deficits in visual cognition, such as in face perception and attentional functions, the characteristics of which already manifest in early infancy.

PURPOSE

This study aimed to investigate visual cognition in LBWIs during infancy.

SUBJECTS

20 LBWIs and 20 normal-birth-weight infants (NBWIs: control) of age 9-10 months (corrected age was used for LBWIs).

METHOD

Children were held seated in front of an eye tracking system by a parent, and presented with facial photos as visual stimuli. During the familiarization phase, the child was presented with two images of the same human face (familiarization stimulus) on the left and right side of a display screen (5 × 10 s trials). Next, during the test phase, the child was presented with the same image on one side of the screen, and a photo of a different person's face (novel stimulus) on the other (2 × 5 s trials). Gaze behavior was assessed in terms of the total time spent looking at either facial stimulus, and specifically at the eyes of the stimuli, as well as the number of attentional shifts between stimuli, and novelty preference.

RESULTS/DISCUSSION

LBWIs spent significant less time looking at facial stimuli overall, and less time at the eye region, than NBWIs. These findings seem to evidence developmental differences in functions related to visual cognition.

Sensitive periods in executive function development

Executive functions (EFs) are cognitive processes that support flexible goal pursuit. Healthy development of EFs during childhood is critical for later life outcomes including health, wealth and educational attainment. As such it is crucial to understand how EFs can be supported and protected against insult. Here we examine whether there are sensitive periods in the development of EFs, by drawing on deprivation and enrichment studies in humans. While there is suggestive evidence that pre-6 months of age constitutes a sensitive period for EF development, given the higher-order nature of EF, we argue for the possibility of multiple sensitive periods of constituent processes. We identify relevant future questions and outline a research agenda to systematically test for sensitive period in EF development.

A Network Perspective on the Relationship between Screen Time, Executive Function, and Fundamental Motor Skills among Preschoolers

The present study aimed to analyze the dynamic and nonlinear association between screen time, executive function (EF), and fundamental motor skills (FMS) in preschoolers, considering sex and body mass index (BMI) from a network perspective. Forty-two preschoolers (24 boys, 3.91 ± 0.77 years old) provided screen time, EF, FMS, and BMI data. EF was measured using the Go/No Go task, and accuracy of Go (sustain attention), reaction time of Go, and accuracy of No Go (inhibitory control) were considered. Relationships between screen time, EF, FMS, sex, and BMI were explored using a network analysis. The emerged network highlights that screen time is intensely associated with the other variables in the network, while the accuracy of Go has the greater connectivity with other nodes in the network (2.27), being the most sensitive to potential intervention changes. Moreover, sex (1.74), screen time (0.93), and accuracy of Go (0.71) showed the greatest closeness. This study showed that in the emerged network, independent of sex, screen exposure affects the accuracy on Go task, and these components affect the variables in the network, as motor abilities and tasks involved in inhibitory control.

Perinatal Maternal Anxiety and Depressive Symptoms and Child Executive Function and Attention at Two-years of Age

The objective was to investigate whether perinatal maternal anxiety and depressive symptoms predicted child attention and executive function (EF). Mothers (N = 614) reported pregnancy and three-months postnatal anxiety and depressive symptoms. Attention and EF were measured at two-years-of-age. Covariates were demographics, alcohol use, mood disorder history, and pregnancy factors. Higher prenatal anxiety, b(SE) =.020(.005), p<.001, and postnatal depressive symptoms, b(SE) =.009(.004), p=.04, predicted poorer child attention. A prenatal-by-postnatal depressive symptom interaction emerged, b(SE) = -.005(.003), p=.04: When pregnancy depressive symptoms were low, higher postnatal symptoms predicted poorer attention. No distress variables predicted EF, p's>.22. Perinatal distress timing, kind, and change were important for child attention.

Associations between individual variations in visual attention at 9 months and behavioral competencies at 18 months in rural Malawi

Theoretical and empirical considerations suggest that individual differences in infant visual attention correlate with variations in cognitive skills later in childhood. Here we tested this hypothesis in infants from rural Malawi (n = 198-377, depending on analysis), who were assessed with eye tracking tests of visual orienting, anticipatory looks, and attention to faces at 9 months, and more conventional tests of cognitive control (A-not-B), motor, language, and socioemotional development at 18 months. The results showed no associations between measures of infant attention at 9 months and cognitive skills at 18 months, either in analyses linking infant visual orienting with broad cognitive outcomes or analyses linking specific constructs between the two time points (i.e., switching of anticipatory looks and manual reaching responses), as correlations varied between -0.08 and 0.14. Measures of physical growth, and family socioeconomic characteristics were also not correlated with cognitive outcomes at 18 months in the current sample (correlations between -0.10 and 0.19). The results do not support the use of the current tests of infant visual attention as a predictive tool for 18-month-old infants' cognitive skills in the Malawian setting. The results are discussed in light of the potential limitations of the employed infant tests as well as potentially unique characteristics of early cognitive development in low-resource settings.

Early microstructure of white matter associated with infant attention

Early infancy is characterized by rapid brain development that occurs alongside, and in response to, the development of cognitive and behavioral functions, including attention. Infants' ability to orient and sustain attention to stimuli develops in concert with refinement of the orienting network in frontoparietal regions of the brain. Infants (n = 97) underwent magnetic resonance imaging at one-month of age and data were fit to a diffusion tensor imaging model to calculate fractional anisotropy (FA) and radial diffusivity (RD), as well as to a neurite orientation dispersion and density imaging model to calculate intracellular volume fraction (νic). Infant attention was assessed at six months of age using a dynamic puppet task (Cuevas and Bell, 2014). Infants with higher FA in the corpus callosum and anterior cingulum showed increased orienting behaviors. Our findings indicate that increased microstructure of the white matter tracts in the orienting network may play a role in the early neurodevelopment of attentional orienting behaviors.

Longitudinal Associations between Parenting and Inattention, Impulsivity, and Delay of Gratification in Preschool-aged Children: The Role of Temperamental Difficultness and Toddler Attention Focusing

Data from the National Institute of Child Health and Human Development Study of Early Child Care were used to test whether maternal sensitivity and stimulation at 15 and 54 months predicted child attention, impulsivity, and delay of gratification at 54 months, and whether toddler attention and temperamental difficultness moderated associations. Maternal sensitivity at 54 months was positively associated with children's delay of gratification and negatively associated with inattention and impulsivity at 54 months. Maternal stimulation at 15 months was negatively associated with inattention at 54 months for toddlers with higher levels of attention focusing and temperamental difficultness. The importance of attending to individual differences is discussed.

M. Van der Ham I, Van der Stigchel S, Oudgenoeg-Paz O. Attentional Flexibility Predicts A-Not-B Task Performance in 14-Month-Old-Infants: A Head-Mounted Eye Tracking Study

Early individual differences in executive functions (EFs) are predictive of a range of developmental outcomes. However, despite the importance of EFs, little is known about the processes underlying these early individual differences. Therefore, we investigated the association between 14-month-old infants’ attention on a reaching version of the A-not-B task and task success. We hypothesized that both strategic focused attention (measured as percentage looking time towards the correct location during delay) and attentional flexibility (measured as number of looks per second to available stimuli during delay) would relate positively to task performance. Infants performed the A-not-B task wearing a head-mounted eye tracker (N = 24). Results were trial-dependent and partially supported the hypotheses: (1) infants who were better able to flexibly shift attention between available stimuli on the first pre-switch trial showed better task performance overall; and (2) strategic focused attention to the hiding location during the first switch trial was positively related to performance on that particular trial only (trend-level effect). Thus, the study shows preliminary evidence that particularly attentional flexibility is a key factor underlying EF performance in young children. Advantages and challenges of working with head-mounted eye tracking in infants are discussed.

Exploring the neural basis of selective and flexible dimensional attention: An fNIRS study

Between the ages of 3 and 5, children develop greater control over attention to visual dimensions. Children develop the ability to flexibly shift between visual dimensions and to selectively process specific dimensions of an object. Previous proposals have suggested that selective and flexible attention are developmentally related to one another (e.g., Hanania & Smith, 2010). However, the relationship between flexibility and selectivity has not been systematically probed at the behavioral and neural levels. We administered a selective attention task (triad classification) along with a flexible attention task (dimensional change card sort) with 3.5- and 4.5-year-olds while functional near-infrared spectroscopy data were recorded. Results showed that children with high flexible attention skills engaged bilateral frontal cortex which replicates previous studies using this task. Moreover, children with high levels of selective attention engaged right frontal cortex. Together, these results indicate that development in right frontal cortex is important for both flexible and selective dimensional attention.

Play enhances visual form perception in infancy-an active training study

Motor experiences and active exploration during early childhood may affect individual differences in a wide range of perceptual and cognitive abilities. In the current study, we suggest that active exploration of objects facilitates the ability to process object forms and magnitudes, which in turn impacts the development of numerosity perception. We tested our hypothesis by conducting a preregistered active exploration intervention with 59 8-month-old infants. The minimal intervention consisted of actively playing with and exploring blocks once a day for 8 weeks. In order to control for possible training effects on attention, we used book reading as a control condition. Pre- and post-test assessments using eye-tracking showed that block play improved visual form perception, where infants became better at detecting a deviant shape. Furthermore, using three control tasks, we showed that the intervention specifically improved infants' ability to process visual forms and the effect could not be explained by a domain general improvement in attention or visual perception. We found that the intervention did not improve numerosity perception and suggest that because of the sequential nature of our hypothesis, a longer time frame might be needed to see improvements in this ability. Our findings indicate that if infants are given more opportunities for play and exploration, it will have positive effects on their visual form perception, which in turn could help their understanding of geometrical concepts.

Longitudinal links between maternal factors and infant cognition: Moderation by infant sleep

The current study examined the moderating role of infant sleep in the link between maternal factors (i.e., maternal education, depressive symptoms, sleep disturbance) and infant cognition. Data come from 95 African American parent-child dyads. At 3 months of age, infant sleep was objectively measured using videosomnography and actigraphy, from which measures of sleep regulation and consolidation were calculated. Mothers also self-reported their level of education, depressive symptoms, and sleep quality. At 6 months of age, infants completed cognitive assessments, including a measure of general cognitive ability and observed attention behavior. Findings revealed that infant sleep quality interacted with maternal education and sleep disturbances to predict cognition. Specifically, the link between maternal education and infants' attention behavior was significant and positive for infants with better regulated sleep, but not for infants with poorly regulated sleep. Similarly, the link between maternal sleep disturbance and infant cognition depended on infant sleep quality. For infants with poorer sleep consolidation, increased maternal sleep disturbance predicted poorer infant general cognitive ability. For infants with better sleep consolidation, maternal sleep disturbance was positively related to both general cognitive ability and attention behavior. These findings suggest that infant sleep quality moderates the impact of environmental factors on cognitive functioning.

Infant screen exposure links to toddlers' inhibition, but not other EF constructs: A propensity score study

Technology is pervasive in homes of families with young children, despite evidence for negative associations between infant exposure to screen-based media and cognitive development that has led the American Academy of Pediatrics (AAP) to discourage parents from exposing children under the age of 18 months to any kind of screen time (AAP, 2016). Here, we apply a propensity score matching approach to estimate relations between electronic screen-based media use in infancy and executive function in early toddlerhood. In an international sample of 416 firstborn infants, parental report of regular exposure to screen-based media at 4 months predicted poorer performance on a test of inhibition at 14 months, but was unrelated to either cognitive flexibility or working memory at 14 months. Results of this study are therefore consistent with the view that early exposure to screen-based media adversely affects the development of executive function.

Executive functions

First, executive functions are defined. Then the development of executive functions in children, from infancy to 10-11 years of age, is briefly described. The relation between the speed of processing and the development of executive functions is addressed. Finally, tools and pointers for evaluating executive functioning in younger and older children are discussed. A cautionary note is sounded, in that almost no executive function measure requires only one executive function. A child might fail a working memory task because of problems with inhibitory control (not working memory), fail an inhibitory control task because of working memory problems, or fail a cognitive flexibility, planning, or reasoning task because of problems with inhibitory control or working memory.

Does Maternal Warmth Moderate Longitudinal Associations Between Infant Attention Control and Children's Inhibitory Control?

Attention control (AC) is thought to play an important role in the development of inhibitory control (IC) in children, yet there are few longitudinal studies of this association. This study used a prospective parent-child adoption design (N = 361 children) to examine whether maternal warmth at child age 27 months moderated the link between AC during infancy and IC during childhood. Tobit regression analyses indicated that low levels of infant AC at 9 months predicted low levels of IC at 6 years, controlling for birth parent IC, prenatal risk, infant distress to limitations, child sex, and openness of adoption. Adoptive mother warmth at 27 months moderated this association. In the context of higher levels of maternal warmth, the longitudinal association between low AC and low IC was attenuated. Thus, high levels of early maternal warmth may help diminish the effects of extant risk for IC deficits.

Early Development of Visual Attention: Change, Stability, and Longitudinal Associations

Visual attention is a basic mechanism of information gathering and environment selection and consequently plays a fundamental role in influencing developmental trajectories. Here, we highlight evidence for predictive associations from early visual attention to emotion regulation, executive function, language and broader cognitive ability, mathematics and literacy skills, and neurodevelopmental conditions. Development of visual attention is also multifaceted and nonlinear. In daily life, core functions such as orienting, selective filtering, and processing of visual inputs are intertwined and influenced by many other cognitive components. Furthermore, the demands of an attention task vary according to the experience, motivation, and cognitive and physical constraints of participants, while the mechanisms underlying performance may change with development. Thus, markers of attention may need to be interpreted differently across development and between populations. We summarize research that has combined multiple measurements and techniques to further our understanding of visual attention development and highlight possibilities for the future.

The role of executive functions in kindergarteners' persistent and non-persistent behaviour

The aim of the study was to examine whether cognitive skills are related to persistence. Thus, children's (N = 157, mean age: 5.9 years) persistent and non-persistent behaviours (i.e., cheating and off-task) were assessed in an unsolvable task. Additionally, we assessed children's executive functions and temperament. Analysis for persistence showed that cognitive inhibition and cognitive flexibility predicted children's persistent behaviour, beyond age and temperament. Analyses for non-persistent behaviours revealed that temperament and weak executive functions predicted cheating, while age predicted off-task behaviour. Statement of contribution What is already known on this subject? So far, persistence has been conceptualized as a temperamental sub-dimension of self-regulation. What does this study add? A child's persistence depends not only on temperament but also on cognitive inhibition and cognitive flexibility. There are qualitative differences between the two non-persistent behaviours cheating and off-task. While cheating is related to weaker cognitive skills, off-task behaviour seems mainly age-related.

Context of Maternal Intrusiveness During Infancy and Associations with Preschool Executive Function

The relation between maternal behavior and neurocognitive development is complex and may depend on the task context. We examined 5-month-old infant frontal EEG, maternal intrusiveness (MI) evaluated during two play contexts at 5 and 10 months, and a battery of executive function (EF) tasks completed at 48 months to evaluate if MI during infancy and infant neural function interacted to predict later cognition. Infant frontal EEG was a predictor of 4-year EF. MI during structured play at both 5 and 10 months predicted preschool EF, and MI during unstructured did not have a main effect on EF but showed a potential moderating effect of infant EEG on later EF. The pattern changed between ages, with MI during structured play at 5 months showing a positive association with age 4 EF, whereas MI during structured play at 10 months had a negative association with age 4 EF. We demonstrate differences in the context of maternal behavior used to predict childhood EF, highlighting the importance of considering parenting context in EF development.

Attention and executive functioning in infancy: Links to childhood executive function and reading achievement

This study provides the first analyses connecting individual differences in infant attention to reading achievement through the development of executive functioning (EF) in infancy and early childhood. Five-month-old infants observed a video, and peak look duration and shift rate were video coded and assessed. At 10 months, as well as 3, 4, and 6 years, children completed age-appropriate EF tasks (A-not-B task, hand game, forward digit span, backwards digit span, and number Stroop). Children also completed a standardized reading assessment and a measure of verbal intelligence (IQ) at age 6. Path analyses on 157 participants showed that infant attention had a direct statistical predictive effect on EF at 10 months, with EF showing a continuous pattern of development from 10 months to 6 years. EF and verbal IQ at 6 years had a direct effect on reading achievement. Furthermore, EF at all time points mediated the relation between 5-month attention and reading achievement. These findings may inform reading interventions by suggesting earlier intervention time points and specific cognitive processes (i.e. 5-month attention).

Fearful Inhibition, Inhibitory Control, and Maternal Negative Behaviors During Toddlerhood Predict Internalizing Problems at Age 6

Many, but not all, young children with high levels of fearful inhibition will develop internalizing problems. Individual studies have examined either child regulatory or environmental factors that might influence the level of risk. We focused on the interaction of regulation and environment by assessing how early fearful inhibition at age 2, along with inhibitory control and maternal negative behaviors at age 3, interactively predicted internalizing problems at age 6. A total of 218 children (105 boys, 113 girls) and their mothers participated in the study. Results indicated a three-way interaction among fearful inhibition, inhibitory control, and maternal negative behaviors. The correlation between fearful inhibition and internalizing was significant only when children had low inhibitory control and experienced high levels of maternal negative behaviors. Either having high inhibitory control or experiencing low maternal negative behaviors buffered against the adverse effect caused by the absence of the other. These findings highlight the importance of considering associations among both within-child factors and environmental factors in studying children's socioemotional outcomes.

A preliminary study on prenatal polybrominated diphenyl ether serum concentrations and intrinsic functional network organization and executive functioning in childhood

BACKGROUND

The prenatal period is a period of vulnerability during which neurotoxic exposures exert persistent changes in brain development and behavior. Polybrominated diphenyl ethers (PBDEs), used as flame retardants in commercial products, are known to be developmental neurotoxicants. PBDEs were phased out of use in the United States a decade ago, but exposure remains widespread due to their release from existing products and biopersistence. Despite consistent animal and epidemiological evidence of developmental neurotoxicity, the neural substrates linking prenatal PBDE serum concentrations to impaired neurodevelopment are poorly understood.

METHODS

In the present study, we used resting state functional magnetic resonance imaging (fMRI) to examine associations between prenatal PBDE concentrations measured in maternal serum and intrinsic functional network organization (i.e., global and local efficiency; estimated using a graph-theoretical approach) in 5-year-old children (n = 34). We explored whether PBDE serum concentrations were associated with executive functioning (EF) assessed using a parent-report questionnaire (BRIEF-P) (n = 106) and whether changes in intrinsic functional network organization linked the association between prenatal PBDE serum concentrations and EF problems.

RESULTS

Children with higher prenatal PBDE serum concentrations showed: (a) increased global efficiency of brain areas involved in visual attention (e.g., inferior occipital gyrus) (β's = .01, FDR-corrected p's ≤ .05); (b) more reported EF problems (β's = .001, FDR-corrected p's ≤ .05). Higher global efficiency of brain areas involved in visual attention was associated with more EF problems (β's = .01, FDR-corrected p's < .05).

CONCLUSIONS

Intrinsic functional network organization of visual attention brain areas linked prenatal PBDE concentrations to EF problems in childhood. Visual attention may contribute to the development of higher-order cognitive functions, such as EF, which could be explored in future studies.

Measuring and Predicting Individual Differences in Executive Functions at 14 Months: A Longitudinal Study

This study of 195 (108 boys) children seen twice during infancy (Time 1: 4.12 months; Time 2: 14.42 months) aimed to investigate the associations between and infant predictors of executive function (EF) at 14 months. Infants showed high levels of compliance with the EF tasks at 14 months. There was little evidence of cohesion among EF tasks but simple response inhibition was related to performance on two other EF tasks. Infant attention (but not parent-rated temperament) at 4 months predicted performance on two of the four EF tasks at 14 months. Results suggest that EF skills build on simpler component skills such as attention and response inhibition.

Sustained attention in infancy: A foundation for the development of multiple aspects of self-regulation for children in poverty

There are many avenues by which early life poverty relates to the development of school readiness. Few studies, however, have examined the extent to which sustained attention, a central component of self-regulation in infancy, mediates relations between poverty-related risk and cognitive and emotional self-regulation at school entry. To investigate longitudinal relations among poverty-related risk, sustained attention in infancy, and self-regulation prior to school entry, we analyzed data from the Family Life Project, a large prospective longitudinal sample (N = 1292) of children and their primary caregivers in predominantly low-income and nonurban communities. We used structural equation modeling to assess the extent to which a latent variable of infant sustained attention, measured in a naturalistic setting, mediated the associations between cumulative poverty-related risk and three domains of self-regulation. We constructed a latent variable of infant sustained attention composed of a measure of global sustained attention and a task-based sustained attention measure at 7 and 15 months of age. Results indicated that infant sustained attention was negatively associated with poverty-related risk and positively associated with a direct assessment of executive function abilities and teacher-reported effortful control and emotion regulation in pre-kindergarten. Mediation analysis indicated that the association between poverty-related risk and each self-regulation outcome was partially mediated by infant attention. These results provide support for a developmental model of self-regulation whereby attentional abilities in infancy act as a mechanism linking the effects of early-life socioeconomic adversity with multiple aspects of self-regulation in early childhood.

Infant Visual Attention and Stimulus Repetition Effects on Object Recognition

This study examined behavioral, heart rate (HR), and event-related potential (ERP) correlates of attention and recognition memory for 4.5-, 6-, and 7.5-month-old infants (N = 45) during stimulus encoding. Attention was utilized as an independent variable using HR measures. The Nc ERP component associated with attention and the late slow wave (LSW) associated with recognition memory were analyzed. The 7.5-month-olds demonstrated a significant reduction in Nc amplitude with stimulus repetition. This reduction in Nc was not found for younger infants. Additionally, infants only demonstrated differential LSW amplitude based on stimulus type on attentive trials as defined by HR changes. These findings indicate that from 4.5 to 7.5 months, infants' attentional engagement is influenced by an increasingly broader range of stimulus characteristics.

Dimensional attention as a mechanism of executive function: Integrating flexibility, selectivity, and stability

In this report, we present a neural process model that explains visual dimensional attention and changes in visual dimensional attention over development. The model is composed of an object representation system that binds visual features such as shape and color to spatial locations and a label learning system that associates labels such as "color" or "shape" with visual features. We have previously demonstrated that this model explains the development of flexible dimensional attention in a task that requires children to switch between shape and color rules for sorting cards. In the model, the development of flexible dimensional attention is a product of strengthening associations between labels and features. In this report, we generalize this model to also explain development of stable and selective dimensional attention. Specifically, we use the model to explain a previously reported developmental association between flexible dimensional attention and stable dimensional attention. Moreover, we generate predictions regarding developmental associations between flexible and selective dimensional attention. Results from an experiment with 3- and 4-year-olds supported model predictions: children who demonstrated flexibility also demonstrated higher levels of selectivity. Thus, the model provides a framework that integrates various functions of dimensional attention, including implicit and explicit functions, over development. This model also provides new avenues of research aimed at uncovering how cognitive functions such as dimensional attention emerge from the interaction between neural dynamics and task structure, as well as understanding how learning dimensional labels creates changes in dimensional attention, brain activation, and neural connectivity.

Funcionamiento ejecutivo y desempeño lector en niños con y sin dificultades de lectura: Un estudio de seguimiento ocular

Introducción: Las funciones ejecutivas incluyen habilidades como la memoria de trabajo, el control inhibitorio, la planeación y la flexibilidad cognitiva. Estas habilidades, resultan fundamentales para el desarrollo de procesos cognitivos complejos como el aprendizaje de la lectoescritura, encontrando que aquellos niños con dificultades de lectura tienden a presentar un nivel menor en el rendimiento en tareas de funciones ejecutivas. Objetivo: Caracterizar el rendimiento en funciones ejecutivas y su relación con el nivel de lenguaje y lectura en niños de 8 a 12 años con dificultades de lectura y sus controles por edad y género en relación a los patrones de seguimiento visual. Método: Participantes: 9 niños con dificultades de lectura y 9 controles. Procedimiento: Se evaluó el nivel de lenguaje, funciones ejecutivas y lectura haciendo uso del Eye Tracker Tobii Tx300.  Se analizaron los mapas de calor, glaze plot y las áreas de interés. Resultados y Conclusiones: Los niños con dificultades de lectura presentan un nivel de desempeño menor en tareas de funciones ejecutivas especialmente en el control inhibitorio y la planeación, estando estas asociadas directamente con el nivel de lenguaje y el rendimiento lector. De igual forma, las métricas visuales a partir del uso del Eye Tracker permite corroborar estas fallas en el procesamiento en tiempo real frente a tareas que implican demandas cognitivas de alto nivel.  

Prenatal Risk Predicts Preschooler Executive Function: A Cascade Model

Little research has considered whether prenatal experience contributes to executive function (EF) development above and beyond postnatal experience. This study tests direct, mediated, and moderated associations between prenatal risk factors and preschool EF and IQ in a longitudinal sample of 1,292 children from the Family Life Project. A composite of prenatal risk factors (i.e., low birth weight, prematurity, maternal emotional problems, maternal prepregnancy obesity, and obstetric complications) significantly predicted EF and IQ at age 3, above quality of the postnatal environment. This relationship was indirect, mediated through infant general cognitive abilities. Quality of the postnatal home and child-care environments did not moderate the cascade model. These findings highlight the role of prenatal experience as a contributor to individual differences in cognitive development.

Neural substrates of early executive function development

In the last decade, advances in neuroimaging technologies have given rise to a large number of research studies that investigate the neural underpinnings of executive function (EF). EF has long been associated with the prefrontal cortex (PFC) and involves both a unified, general element, as well as the distinct, separable elements of working memory, inhibitory control and set shifting. We will highlight the value of utilising advances in neuroimaging techniques to uncover answers to some of the most pressing questions in the field of early EF development. First, this review will explore the development and neural substrates of each element of EF. Second, the structural, anatomical and biochemical changes that occur in the PFC during infancy and throughout childhood will be examined, in order to address the importance of these changes for the development of EF. Third, the importance of connectivity between regions of the PFC and other brain areas in EF development is reviewed. Finally, throughout this review more recent developments in neuroimaging techniques will be addressed, alongside the implications for further elucidating the neural substrates of early EF development in the future.

Infant Attention and Age 3 Executive Function

Executive function (EF) abilities refer to higher order cognitive processes necessary to consciously and deliberately persist in a task and are associated with a variety of important developmental outcomes. Attention is believed to support the development and deployment of EF. Although preschool EF and attentional abilities are concurrently linked, much less is known about the longitudinal association between infant attentional abilities and preschool EF. The current study investigated the impact of infant attention orienting behavior on preschool EF. Maternal report and laboratory measures of infant attention were gathered on 114 infants who were 5 months old; performance on four different EF tasks was measured when these same children were 3 years old. Infant attention skills were significantly related to preschool EF, even after controlling for age 3 verbal intelligence. These findings indicate that infant attention may indeed serve as an early marker of later EF. Given the significant developmental outcomes associated with EF, understanding the foundational factors associated with EF is necessary for both theoretical and practical purposes.

Beyond the Bayley: Neurocognitive Assessments of Development During Infancy and Toddlerhood

The use of global, standardized instruments is conventional among clinicians and researchers interested in assessing neurocognitive development. Exclusively relying on these tests for evaluating effects may underestimate or miss specific effects on early cognition. The goal of this review is to identify alternative measures for possible inclusion in future clinical trials and interventions evaluating early neurocognitive development. The domains included for consideration are attention, memory, executive function, language, and socioemotional development. Although domain-based tests are limited, as psychometric properties have not yet been well-established, this review includes tasks and paradigms that have been reliably used across various developmental psychology laboratories.

Threat-related Attention Bias in Socioemotional Development: A Critical Review and Methodological Considerations

Cross-sectional evidence suggests that attention bias to threat is linked to anxiety disorders and anxiety vulnerability in both children and adults. However, there is a lack of developmental evidence regarding the causal mechanisms through which attention bias to threat might convey risks for socioemotional problems, such as anxiety. Gaining insights into this question demands longitudinal research to track the complex interplay between threat-related attention and socioemotional functioning. Developing and implementing reliable and valid assessments tools is essential to this line of work. This review presents theoretical accounts and empirical evidence from behavioral, eye-tracking, and neural assessments of attention to discuss our current understanding of the development of normative threat-related attention in infancy, as well as maladaptive threat-related attention patterns that may be associated with the development of anxiety. This review highlights the importance of measuring threat-related attention using multiple attention paradigms at multiple levels of analysis. In order to understand if and how threat-related attention bias in real-life, social interactive contexts can predict socioemotional development outcomes, this review proposes that future research cannot solely rely on screen-based paradigms but needs to extend the assessment of threat-related attention to naturalistic settings. Mobile eye-tracking technology provides an effective tool for capturing threat-related attention processes in vivo as children navigate fear-eliciting environments and may help us uncover more proximal bio-psycho-behavioral markers of anxiety.

Examining the Associations Between Performance Based and Ratings of Focused Attention in Toddlers: Are We Measuring the Same Constructs?

The study examines the concurrent and longitudinal associations between ratings-based measures (parents, secondary caregivers, observers) and performance-based measures of focused attention in toddlers aged 30- (n = 147), 36- (n =127), and 42-months (n =107). Parents and secondary caregivers rated focused attention behaviors using the Children's Behavior Questionnaire (Rothbart et al., 2001), and observers rated toddlers' focused attention during a series of laboratory tasks using the Leiter-R Examiner Rating Scale (Roid & Miller, 1997). Toddlers' behaviors on three structured tasks (Token Sort, Toy Play, Lock Box) were used to assess their performance based focused attention in a laboratory setting. Correlations show that parent ratings are not related to observer and teacher ratings, or to the performance-based measures at all ages tested. Second, based on confirmatory factor analyses, a single factor explains the common variance between indicators when the parent ratings are not included in the models. The single factor shows measurement invariance between ages 36 and 42 months based on factor structure, relations of indicators to the factor, and factor scale over time. Third, indicators of focused attention at age 30 months do not seem to measure a common, coherent factor. Interpretations of similarities and differences between ratings and performance-based indicators of focused attention and the presence of a focused attention construct are discussed.

Individual differences in visual attention and self-regulation: A multimethod longitudinal study from infancy to toddlerhood

Given the importance of self-regulation for a broad range of developmental outcomes, identifying reliable precursors of self-regulation early in development is important for early prevention of developmental problems. The aim of this study was to examine whether three visual attention measures (fixation duration, variation in fixation duration, and disengagement) in infancy (9.10-11.43 months of age) predicted effortful control and compliance in toddlerhood (26.71-31.80 months). The sample consisted of 74 children (50% boys). In infancy, two eye-tracking tasks were conducted: a visual search task to assess fixation duration and variation in fixation duration (n = 58) and the gap-overlap task to assess disengagement (n = 49). In toddlerhood, children's effortful control (n = 65) and compliance (n = 65) were assessed by parent reports and observed during a delay of gratification task and a cleanup session together with the parents, respectively. Using full information maximum likelihood to account for missing data, multiple regression analyses revealed that, when all three measures of visual attention were taken into account, longer fixations and less variation in fixation duration in infancy predicted better effortful control. Disengagement did not predict effortful control. Compliance in toddlerhood was not predicted by any of the visual attention measures. These findings may indicate that visual attentional measures in infancy predict relatively independent forms of self-regulation in toddlerhood. Future studies are necessary to elucidate the mechanisms that underlie the association between (variation in) fixation duration in infancy and effortful control in toddlerhood.

Early Detection of ADHD: Insights From Infant Siblings of Children With Autism

Converging evidence suggests shared genetic underpinnings of attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Studies of infants at risk for ASD have proliferated over the past decade; the few studies that have followed these infants beyond age 3 report a range of difficulties facing a subset of these infants as they reach school age, including elevated levels of attention problems and externalizing behavior. Given this, we aimed to identify early predictors of school-age ADHD outcomes in a sample of infant siblings at risk for ASD. This study reports on a sample of 59 infants at high and low risk for ASD who had been followed for more than a decade, collecting data at regular intervals from 3 to 36 months and then determining diagnostic outcome at 8-10 years of age. Seventeen participants were diagnosed with Diagnostic and Statistical Manual of Mental Disorders (5th ed.) ADHD at school age (n = 14 high risk, 3 low risk). As infants, the ADHD outcome group demonstrated atypical longitudinal patterns of sustained visual attention. A significantly larger proportion of their parents reported behavior/temperament problems at 36 months of age, and examiners noted the presence of inattentive, hyperactive, and/or impulsive behaviors in this group by 18 months of age. These data suggest that behavioral indicators of risk for later ADHD may be present early in development, which may improve earlier detection and treatment of the disorder.

Rapid Infant Prefrontal Cortex Development and Sensitivity to Early Environmental Experience

Over the last fifteen years, the emerging field of developmental cognitive neuroscience has described the relatively late development of prefrontal cortex in children and the relation between gradual structural changes and children's protracted development of prefrontal-dependent skills. Widespread recognition by the broader scientific community of the extended development of prefrontal cortex has led to the overwhelming perception of prefrontal cortex as a "late developing" region of the brain. However, despite its supposedly protracted development, multiple lines of research have converged to suggest that prefrontal cortex development may be particularly susceptible to individual differences in children's early environments. Recent studies demonstrate that the impacts of early adverse environments on prefrontal cortex are present very early in development: within the first year of life. This review provides a comprehensive overview of new neuroimaging evidence demonstrating that prefrontal cortex should be characterized as a "rapidly developing" region of the brain, discusses the converging impacts of early adversity on prefrontal circuits, and presents potential mechanisms via which adverse environments shape both concurrent and long-term measures of prefrontal cortex development. Given that environmentally-induced disparities are present in prefrontal cortex development within the first year of life, translational work in intervention and/or prevention science should focus on intervening early in development to take advantages of this early period of rapid prefrontal development and heightened plasticity.

Verbal and nonverbal predictors of executive function in early childhood

The study of executive function (EF) has become increasingly popular in multiple areas of research. A wealth of evidence has supported the value of EF in shaping notable outcomes across typical and atypical development; however, little evidence has supported the cognitive contributors to early EF development. The current study used data from a large longitudinal sample of healthy children to investigate the differential influence of verbal and nonverbal cognition on later EF. Participants were assessed at 2 years of age using the Mullen Scales of Early Learning, and Mullen scores were used to calculate nonverbal and verbal developmental quotients. Executive function was measured at 6 years using assessments from the Stanford-Binet, Cambridge Neuropsychological Test Automated Battery, and the Behavior Rating Inventory of Executive Function. Results suggested that early nonverbal cognition was a better predictor of 6-year EF as measured by task-based laboratory assessments, whereas verbal cognition was a better predictor of parent-reported EF. Findings are discussed in regard to EF development and characteristics of EF measurement.

Developmental change in look durations predicts later effortful control in toddlers at familial risk for ASD

BACKGROUND

Difficulties with executive functioning (EF) are common in individuals with a range of developmental disorders, including autism spectrum disorder (ASD). Interventions that target underlying mechanisms of EF early in development could be broadly beneficial, but require infant markers of such mechanisms in order to be feasible. Prospective studies of infants at high familial risk (HR) for ASD have revealed a surprising tendency for HR toddlers to show longer epochs of attention to faces than low-risk (LR) controls. In typical development, decreases in look durations towards the end of the first year of life are driven by the development of executive attention-a foundational component of EF. Here, we test the hypothesis that prolonged attention to visual stimuli (including faces) in HR toddlers reflects early differences in the development of executive attention.

METHODS

In a longitudinal prospective study, we used eye-tracking to record HR and LR infants' looking behaviour to social and non-social visual stimuli at ages 9 and 15 months. At age 3 years, we assessed children with a battery of clinical research measures and collected parental report of effortful control (EC)-a temperament trait closely associated with EF and similarly contingent on executive attention.

RESULTS

Consistent with previous studies, we found an attenuated reduction in peak look durations to faces between 9 and 15 months for the HR group compared with the LR group, and lower EC amongst the HR-ASD group. In line with our hypothesis, change in peak look duration to faces between 9 and 15 months was negatively associated with EC at age 3.

CONCLUSIONS

We suggest that for HR toddlers, disruption to the early development of executive attention results in an attenuated reduction in looking time to faces. Effects may be more apparent for faces due to early biases to orient towards them; further, attention difficulties may interact with earlier emerging differences in social information processing. Our finding that prolonged attention to faces may be an early indicator of disruption to the executive attention system is of potential value in screening for infants at risk for later EF difficulties and for evaluation of intervention outcomes.

Cognition-Action Trade-Offs Reflect Organization of Attention in Infancy

This chapter discusses what cognition-action trade-offs in infancy reveal about the organization and developmental trajectory of attention. We focus on internal attention because this aspect is most relevant to the immediate concerns of infancy, such as fluctuating levels of expertise, balancing multiple taxing skills simultaneously, learning how to control attention under variable conditions, and coordinating distinct psychological domains. Cognition-action trade-offs observed across the life span include perseveration during skill emergence, errors and inefficient strategies during decision making, and the allocation of resources when attention is taxed. An embodied cognitive-load account interprets these behavioral patterns as a result of limited attentional resources allocated across simultaneous, taxing task demands. For populations where motor errors could be costly, like infants and the elderly, attention is typically devoted to motor demands with errors occurring in the cognitive domain. In contrast, healthy young adults tend to preserve their cognitive performance by modifying their actions.

Executive function assessment in New Zealand 2-year olds born at risk of neonatal hypoglycemia

A growing number of babies are born with perinatal risk factors that may impair later development. These children are often assessed at 2 years to help predict outcome and direct support services. Executive function is an important predictor of academic achievement and behavior, but there are limited assessments of executive function in 2-year-olds and few have been tested in at-risk populations. Therefore, we developed a battery of four age-appropriate tasks to assess executive function in 2-year-olds. At 24 months’ corrected age 368 children completed tasks assessing attention, inhibition, working memory and cognitive flexibility. Scores on different tasks were weakly correlated, suggesting that they measured separate aspects of executive function, with combined scores for this cohort approximating a normal distribution. Significantly more boys (67%) than girls (57%) were unable to inhibit their behavior on the Snack Delay Task and girls (M = 3.24, SD = 2.4) had higher mean scores than boys (M = 2.7, SD = 2.7) on the Ducks and Buckets Reverse Categorization Task of working memory. Performance was significantly affected by family socioeconomic status. Mean scores were lower on all four individual tasks and on the global score of overall performance in children from a low household income (<$40,000) compared to those from medium ($40,001-$70,000) and high income households (>$70,001). Maternal education was only associated with scores on the working memory task and the global score; and a measure of neighborhood deprivation was only associated with scores on the two inhibitory tasks and the global score. Our findings confirm the feasibility of assessing executive function in 2-year-olds, and its ability to discriminate effects of socioeconomic status, a common confounder in child development research. Further development and standardization of this test battery comparing at-risk children with a normative population would provide a much-needed measure of executive function in early childhood.

Early executive function differences in infants born moderate-to-late preterm

Individuals who are born very preterm (<32weeks gestation) show differential development of prefrontal cortex structure, function, and dependent behaviors, including executive function (EF) skills, beginning during late infancy and extending into adulthood. Preschool-aged children born moderate-to-late preterm (PT; 32-36weeks gestation) show smaller discrepancies in EF development, but it is unclear whether these differences first emerge during the early childhood years, when EF is rapidly developing, or if they arise from alterations in complex cognitive skills measurable in late infancy. In the current study, we examined whether differences in complex attention, memory, and inhibition skills (precursor skills to EF) are altered in healthy infants born moderate-to-late PT at 9-months corrected age. Infants born PT demonstrated poorer memory at test following habituation than their full-term peers. Furthermore, lower gestational age at birth was associated with poorer performance on five of the six early EF tasks. Results indicate that even in the context of low medical and environmental risk, performance on the Bayley within the normal range, and no group-level differences in processing speed, infants born moderate-to-late PT show subtle alterations in cognitive skills presumed to be dependent on prefrontal cortex by 9-months of age, likely setting the stage for long-term differences in EF development.

Physical Activity and Cognitive Development: A Meta-Analysis

RESEARCH QUESTION

Is there an association between regular exercise, defined as a structured program of increased physical activity at least 1 month in duration, and improvements in measures of executive functions compared with children who engage in their normal daily activities?

CONTEXT

The association between increased physical activity and changes in performance on tasks of executive functions have not been well elucidated in children. Executive functioning is important to intellectual development and academic success in children, and inexpensive, nonpharmacological methods for the treatment of executive dysfunction represent an attractive interventional target.

OBJECTIVE

To estimate the effect of a structured regular exercise program on neuropsychological domains of executive function in children ages 7 to 12.

DATA SOURCES

We performed a systematic review of English and non-English articles using Cochrane Library, EBSCO CINAHL, Ovid MEDLINE, PSYCInfo, Pubmed, and Web of Science, including all years allowed by each individual search engine. The search string used was "(exercise OR phys*) AND (cognit* OR executive) AND (child* OR preadolesc*)." The authors of the studies selected for review were contacted for any unpublished data.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials, which enrolled children between the ages of 7 and 12, with randomization to either normal activity or a structured physical activity intervention consisting of scheduled aerobic exercise, at least once per week, for a period of at least 1 month. Eligible studies must have included a neuropsychological battery of tests that measured at least 1 executive function both before and after the intervention was completed.

STUDY APPRAISAL

Two independent reviewers examined the screened studies in detail for potential inclusion. The results of the individual examinations were compared; if any discrepancies were present, a third party analyzed the study to determine if it should be included in the meta-analysis.

RESULTS

A total of 18 studies were identified by abstract as candidates for inclusion. From these 18 studies, 8 were independently selected by 2 authors for inclusion in the final analysis; there were no selection discrepancies between authors with regard to the studies to be included. In all, 770 subjects were included, 339 in the control group and 431 in the intervention group. All 8 studies contained a measure of inhibitory control; no other domain of executive function was measured frequently enough to perform meta-analysis, so only measures of inhibitory control were pooled and analyzed. A Cohen d effect size was calculated for each measure using the method of Morris for controlled pre-post control measurement studies. The studies were then combined in a random effects model using Comprehensive Meta Analysis software (Biostat, Englewood, NJ) for Windows (Microsoft, Redmond, WA). All studies showed a positive effect of regular exercise with improvements in measures of inhibitory control, but none were statistically significant for this measure. When pooled, the model revealed a combined Cohen d effect size of 0.2 (95% confidence interval, 0.03-0.37; P=0.021), indicating a small improvement of inhibitory control with long-term physical activity. Heterogeneity was very low (I=0).

LIMITATIONS

Many studies used different neuropsychological tests to assess inhibitory control, which may have introduced unforeseen confounders. Other domains of executive functions were not measured frequently enough to perform meta-analysis. Despite attempts to gather unpublished data, positive results were observed in all of the included studies, raising the possibility of publication bias.

CONCLUSIONS AND IMPLICATIONS

Increased regular physical activity is associated with a small and measurable, improvement in neuropsychological tests of executive functions, specifically inhibitory control. Executive functions play an important role in complex behavior, and may contribute to academic and career achievement as well as success in social interaction. This finding provides support for the important interaction between exercise and cognitive functioning.

Prenatal phthalate exposures and child temperament at 12 and 24 months

INTRODUCTION

Gestational phthalate exposures have been adversely associated with attention, externalizing, and internalizing behaviors in childhood. Early childhood temperament may be a marker of later behavioral patterns. We therefore sought to determine whether gestational phthalate exposures were associated with infant and toddler temperament.

METHODS

The Mount Sinai Children's Environmental Health Study is a prospective cohort study of children born between May 1998 and July 2001 in New York City (N=404). Phthalate metabolites were measured in spot urine samples collected from pregnant women in their third trimester. Child temperament was assessed by parental report at 12-months using the Infant Behavior Questionnaire (IBQ) (N=204) and at 24-months using the Toddler Behavior Assessment Questionnaire (TBAQ) (N=279). We used multiple linear regression to evaluate associations between urinary phthalate metabolites and eleven temperament domains.

RESULTS

Phthalate biomarker concentrations were weakly associated with lower gross motor activity levels as well as higher duration of orienting at the 12-month assessment. Mono(3-carboxypropyl) phthalate (MCPP), monobenzyl phthalate (MBzP) and the sum of metabolites of di(2-ethylhexyl) phthalate (∑DEHP) were associated with lower levels of smiling and laughing at 12 months. At 24-months, social fear and lower pleasure was linked to higher concentrations of MCPP and MBzP, and higher ∑DEHP was weakly associated with increased anger levels at 24-months.

CONCLUSIONS

Though we observed some weak associations between biomarkers of prenatal exposure to phthalates and temperament at 12- and 24-months, overall phthalates biomarkers were not strongly associated with alterations in temperament.

Modeling Infant i's Look on Trial t: Race-Face Preference Depends on i's Looking Style

When employing between-infant designs young infants' looking style is related to their development: Short looking (SL) infants are cognitively accelerated over their long looking (LL) peers. In fact, looking style is a within-infant variable, and depends on infant i's look distribution over trials. For the paired array setting, a model is provided which specifies the probability, π_i ∈ [0, 1], that i is SL. The model is employed in a face preference study; 74 Caucasian infants were longitudinally assessed at 3, 6, and 9 months. Each i viewed same race (Caucasian) vs. other race (African) faces. Infants become SL with development, but there are huge individual differences in rate of change over age. Three month LL infants, π^i<1/2, preferred other race faces. SL infants, π^i>1/2, preferring same race faces at 3, and other race faces at 6 and 9 months. Looking style changes precede and may control changes in face preference. Ignoring looking style can be misleading: Without considering looking style, 3 month infants show no face preference.

The influence of CHRNA4, COMT, and maternal sensitivity on orienting and executive attention in 6-month-old infants

Despite claims concerning biological mechanisms sub-serving infant attention, little experimental work examines its underpinnings. This study examines how candidate polymorphisms from the cholinergic (CHRNA4 rs1044396) and dopaminergic (COMT rs4680) systems, respectively indicative of parietal and prefrontal/anterior cingulate involvement, are related to 6-month-olds' (n=217) performance during a visual expectation eye-tracking paradigm. As previous studies suggest that both cholinergic and dopaminergic genes may influence susceptibility to the influence of other genetic and environmental factors, we further examined whether these candidate genes interact with one another and/or with early caregiving experience in predicting infants' visual attention. We detected an interaction between CHRNA4 genotype and observed maternal sensitivity upon infants' orienting to random stimuli and a CHRNA4-COMT interaction effect upon infants' orienting to patterned stimuli. Consistent with adult research, we observed a direct effect of COMT genotype on anticipatory looking to patterned stimuli. Findings suggest that CHRNA4 genotype may influence susceptibility to other attention-related factors in infancy. These interactions may account for the inability to establish a link between CHRNA4 and orienting in infant research to date, despite developmental theorizing suggesting otherwise. Moreover, findings suggest that by 6months, dopamine, and relatedly, the prefrontal cortex/anterior cingulate, may be important to infant attention.

The effects of stimulus symmetry on hierarchical processing in infancy

The current study investigated the effects of stimulus symmetry on the processing of global and local stimulus properties by 6-month-old short- and long-looking infants through the use of event-related potentials (ERPs). Previous research has shown that individual differences in infant visual attention are related to hierarchical stimulus processing, such that short lookers show a global processing bias, while long lookers demonstrate a local processing bias (Guy, Reynolds, & Zhang, 2013). Additional research has shown that in comparison with asymmetry, symmetry is associated with more efficient stimulus processing and more accurate memory for stimulus configuration (Attneave, 1955; Perkins, 1932). In the current study, we utilized symmetric and asymmetric hierarchical stimuli and predicted that the presence of asymmetry would direct infant attention to the local features of stimuli, leading short lookers to regress to a local processing strategy. Results of the ERP analysis showed that infants familiarized with a symmetric stimulus showed evidence of global processing, while infants familiarized with an asymmetric stimulus did not demonstrate evidence of processing at the global or local level. These findings indicate that short- and long-looking infants, who might otherwise fail to process global stimulus properties due to limited visual scanning, may succeed at global processing when exposed to symmetric stimuli. Furthermore, stimulus symmetry may recruit selective attention toward global properties of visual stimuli, facilitating higher-level cognitive processing in infancy.

Temporal Dependency and the Structure of Early Looking

Although looking time is used to assess infant perceptual and cognitive processing, little is known about the temporal structure of infant looking. To shed light on this temporal structure, 127 three-month-olds were assessed in an infant-controlled habituation procedure and presented with a pre-recorded display of a woman addressing the infant using infant-directed speech. Previous individual look durations positively predicted subsequent look durations over a six look window, suggesting a temporal dependency between successive infant looks. The previous look duration continued to predict the subsequent look duration after accounting for habituation-linked declines in look duration, and when looks were separated by an inter-trial interval in which no stimulus was displayed. Individual differences in temporal dependency, the strength of associations between consecutive look durations, are distinct from individual differences in mean infant look duration. Nevertheless, infants with stronger temporal dependency had briefer mean look durations, a potential index of stimulus processing. Temporal dependency was evident not only between individual infant looks but between the durations of successive habituation trials (total looking within a trial). Finally, temporal dependency was evident in associations between the last look at the habituation stimulus and the first look at a novel test stimulus. Thus temporal dependency was evident across multiple timescales (individual looks and trials comprised of multiple individual looks) and persisted across conditions including brief periods of no stimulus presentation and changes from a familiar to novel stimulus. Associations between consecutive look durations over multiple timescales and stimuli suggest a temporal structure of infant attention that has been largely ignored in previous work on infant looking.