Developmental Delays in Executive Function from 3 to 5 Years of Age Predict Kindergarten Academic Readiness

Substantial evidence has established that individual differences in executive function (EF) in early childhood are uniquely predictive of children’s academic readiness at school entry. The current study tested whether growth trajectories of EF across the early childhood period could be used to identify a subset of children who were at pronounced risk for academic impairment in kindergarten. Using data that were collected at the age 3, 4, and 5 home assessments in the Family Life Project (N = 1,120), growth mixture models were used to identify 9% of children who exhibited impaired EF performance (i.e., persistently low levels of EF that did not show expected improvements across time). Compared to children who exhibited typical trajectories of EF, the delayed group exhibited substantial impairments in multiple indicators of academic readiness in kindergarten (Cohen’s ds = 0.9–2.7; odds ratios = 9.8–23.8). Although reduced in magnitude following control for a range of socioeconomic and cognitive (general intelligence screener, receptive vocabulary) covariates, moderate-sized group differences remained (Cohen’s ds = 0.2–2.4; odds ratios = 3.9–5.4). Results are discussed with respect to the use of repeated measures of EF as a method of early identification, as well as the resulting translational implications of doing so

Integrating Item Accuracy and Reaction Time to Improve the Measurement of Inhibitory Control Abilities in Early Childhood

Efforts to improve children’s executive function are often hampered by the lack of measures that are optimized for use during the transition from preschool to elementary school. Whereas preschool-based measures often emphasize response accuracy, elementary school-based measures emphasize reaction time (RT)—especially for measures inhibitory control (IC) tasks that typically have a speeded component. The primary objective of this study was to test in a preschool-aged sample whether the joint use of item-level accuracy and RT data resulted in improved scoring for three IC tasks relative to scores derived from accuracy data alone. Generally, the joint use of item-level accuracy and RT data resulted in modest improvements in the measurement precision of IC abilities. Moreover, the joint use of item-level accuracy and RT helped eliminate floor and ceiling effects that occurred when accuracy data were considered alone. Results are discussed with respect to the importance of scoring IC tasks in ways that are maximally informative for program evaluation and longitudinal modeling

Measuring executive function in early childhood: A case for formative measurement.

This study tested whether individual executive function (EF) tasks were better characterized as formative (causal) or reflective (effect) indicators of the latent construct of EF. EF data that were collected as part of the Family Life Project (FLP), a prospective longitudinal study of families who were recruited at the birth of a new child (N = 1292), when children were 3, 4, and 5 years old. Vanishing tetrad tests were used to test the relative fit of models in which EF tasks were used as either formative or reflective indicators of the latent construct of EF in the prediction of intellectual ability (at age 3), attention deficit/hyperactivity disorder symptoms (at ages 3–5 years), and academic achievement (at kindergarten). Results consistently indicated that EF tasks were better represented as formative indicators of the latent construct of EF. Next, individual tasks were combined to form an overall measure of EF ability in ways generally consistent with formative (i.e., creating a composite mean score) and reflective (i.e., creating an EF factor score) measurement. The test-retest reliability and developmental trajectories of EF differed substantially, depending on which overall measure of EF ability was used. In general, the across-time stability of EF was markedly higher, perhaps implausibly high, when represented as a factor score versus composite score. Results are discussed with respect to the ways in which the statistical representation of EF tasks can exert a large impact on inferences regarding the developmental causes, course, and consequences of EF. More generally, these results exemplify how some psychological constructs may not conform to conventional measurement wisdom

Near-Infrared Spectroscopy Shows Right Parietal Specialization for Number in Pre-Verbal Infants

Bilateral regions of the intraparietal sulcus (IPS) appear to be functionally selective for both rudimentary non-symbolic number tasks and higher-level symbolic number tasks in adults and older children. Furthermore, the ability to mentally represent and manipulate approximate non-symbolic numerical quantities is present from birth. These factors leave open whether the specialization of the IPS develops through the experience of learning a symbolic number system or if it is already specialized before symbolic number acquisition. Using the newly emerging technique of functional Near-Infrared Spectroscopy (fNIRS) over left and right parietal and lateral occipital regions, we show right parietal specialization for number in 6-month-old infants. These results extend the current literature in three ways: by successfully implementing an event-related NIRS design in infants, by showing parietal specialization for number occurs before the acquisition of language, and by suggesting number representation may be initially right lateralized and become bilateral through experience.Psycholog

Salivary cortisol and cognitive development in infants from low-income communities

Early stress exposure is proposed to have significant lasting effects on cognitive development. The glucocorticoid hormone cortisol, a product of the hypothalamic-pituitary-adrenal (HPA) axis, is a particular focus of research, however, the majority of past research has been based on studies of older children and adults. Evidence linking cortisol levels in infancy with cognitive development is lacking. In a large cohort sample of infants (N = 1,091) oversampled for psychosocial risk, we tested whether basal cortisol levels and cortisol reactivity to emotional stressors administered at 7 and 15 months of age were associated with cognitive development measured at 15 months. Cognitive development was measured using the Mental Development Index of the Bayley Scales of Infant Development. Multiple regression analyses indicated that basal cortisol levels at 15 months, and to a lesser extent at 7 months, were inversely associated with infant cognitive development after adjusting for psychosocial and obstetric risk. The findings provide some of the first evidence that HPA axis activity in infancy is associated with early cognitive development

The Benefits of Adding a Brief Measure of Simple Reaction Time to The Assessment of Executive Function Skills in Early Childhood

Early childhood represents a period of rapid cognitive developmental change in executive function (EF) skills along with a variety of related cognitive processes, including processing speed. This leads to interpretational challenges in that children’s performance on EF tasks reflects more than EF skills per se. We tested whether the inclusion of a brief measure of simple reaction time (SRT) during EF assessments could help to partially address this challenge. Data were drawn from a cross-sectional convenience sample of 830 preschool-aged children. Individual differences in SRT were significantly associated with performance on all tasks (R2s = .09–.26); slower performance on the SRT task was associated with poorer performance on each EF task. Age-related differences in individual EF tasks were reduced by approximately one half after accounting for age-related differences in SRT, and EF task scores were less coherent (i.e., less strongly intercorrelated with each other) after the removal of SRT. Age-related differences in EF were smaller (Cohen ds = 1.36 vs. 0.78), and poverty-related differences in EF were larger (Cohen ds = 0.30 vs. 0.46) after accounting for SRT-related variation. Finally, consistent with previous studies, SRT-related differences in fluid reasoning were mediated by EF skills. Results are discussed with respect to using a brief measure of SRT to partially address the problem of measurement impurity at the level of individual EF tasks

Neurobiology of Self-Regulation: Longitudinal Influence of FKBP5 and Intimate Partner Violence on Emotional and Cognitive Development in Childhood.

OBJECTIVE::Self-regulation includes the volitional and nonvolitional regulation of emotional, cognitive, and physiological responses to stimulation. It develops from infancy through individual characteristics and the environment, with the stress hormone system as a central player. Accordingly, the authors hypothesized that genes involved in regulating the stress system, such as FK506 binding protein 5 (FKBP5), interact with early-life stress exposure, such as exposure to intimate partner violence (IPV), to predict self-regulation indicators and associated outcomes, including behavioral and learning problems in school. METHODS::Study participants were a longitudinal birth cohort of 910 children for whom FKBP5 genotypes were available and who were assessed for exposure to IPV during the first 2 years of life as well as multiple measures of self-regulation: stress-induced cortisol reactivity and fear-elicited emotional reactivity at 7, 15, and 24 months, executive function at 36, 48, and 60 months, and emotional and behavioral difficulties and reading and math achievement in school grades 1, 2, and 5. Data were analyzed using longitudinal clustering and ordinal logistic regression procedures followed by mixed linear modeling. RESULTS::Children with two copies of a risk FKBP5 haplotype and IPV exposure were significantly more likely to have a developmental trajectory characterized by high, prolonged stress-induced cortisol reactivity and emotional reactivity in toddlerhood, followed by low executive function at school entry and high emotional and behavior problems and low reading ability in the primary school grades. CONCLUSIONS::The interaction of FKBP5 and IPV affects the physiological response to stress early in life, with consequences for emotional and cognitive self-regulation. Targeting self-regulation may present an early intervention strategy for children facing genetic and environmental risk

Censored data considerations and analytical approaches for salivary bioscience data

Left censoring in salivary bioscience data occurs when salivary analyte determinations fall below the lower limit of an assay’s measurement range. Conventional statistical approaches for addressing censored values (i.e., recoding as missing, substituting or extrapolating values) may introduce systematic bias. While specialized censored data statistical approaches (i.e., Maximum Likelihood Estimation, Regression on Ordered Statistics, Kaplan-Meier, and general Tobit regression) are available, these methods are rarely implemented in biobehavioral studies that examine salivary biomeasures, and their application to salivary data analysis may be hindered by their sensitivity to skewed data distributions, outliers, and sample size. This study compares descriptive statistics, correlation coefficients, and regression parameter estimates generated via conventional and specialized censored data approaches using salivary C-reactive protein data. We assess differences in statistical estimates across approach and across two levels of censoring (9% and 15%) and examine the sensitivity of our results to sample size. Overall, findings were similar across conventional and censored data approaches, but the implementation of specialized censored data approaches was more efficient (i.e., required little manipulations to the raw analyte data) and appropriate. Based on our review of the findings, we outline preliminary recommendations to enable investigators to more efficiently and effectively reduce statistical bias when working with left-censored salivary biomeasure data

From perpetrator to peacebuilder: rethinking education in conflict-affected societies

This chapter explores the nexus between education and confict, positioning education as a contested domain that shapes, and is shaped by, a broad range of social, political, economic and cultural dynamics in confict-afected societies. On the one hand, violent conficts and structural violence have detrimental efects on educational processes and outcomes. On the other hand, education itself can (re)produce structural violence in society. Bringing together the felds of social science and cognitive neuroscience, this chapter provides a multi-faceted lens through which to address the challenges of education in diferent confict contexts from around the world, highlighting that the search for a collective peaceful future is complex

Poverty as a predictor of 4-year-olds' executive function: New perspectives on models of differential susceptibility.

In a predominantly low-income, population-based longitudinal sample of 1,259 children followed from birth, results suggest that chronic exposure to poverty and the strains of financial hardship were each uniquely predictive of young children’s performance on measures of executive functioning. Results suggest that temperament-based vulnerability serves as a statistical moderator of the link between poverty-related risk and children’s executive functioning. Implications for models of ecology and biology in shaping the development of children’s self-regulation are discussed