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

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

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

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

Contributions of modern measurement theory to measuring executive function in early childhood: An empirical demonstration

This study demonstrates the merits of evaluating a newly developed battery of executive function tasks, designed for use in early childhood, from the perspective of item response theory (IRT). The battery was included in the 48-month assessment of the Family Life Project, a prospective longitudinal study of 1292 children oversampled from low-income and African American families. IRT models were applied to a select set of tasks to demonstrate empirically (a) a principled method for item evaluation, including the utility of item characteristic curves; (b) how to explicitly test whether the measurement properties of executive function tasks are invariant across mutually exclusive subgroups of youths; (c) how the precision of measurement of a given task can vary according to underlying child ability; and (d) the utility of using IRT-based versus percentage correct scores. Results are discussed with respect to the importance of developing psychometrically sound and scalable instrument

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

Childhood sexual trauma and subsequent parenting beliefs and behaviors

Using propensity-matched controls, the present study examines the long-term adjustment of women reporting Childhood Sexual Trauma (CST) at or before the age of 14 in terms of parenting efficacy and parenting behavior. Data for these analyses were obtained from mother reports and from observational protocols from a longitudinal study of low-income, rural families. The novel use of propensity-matched controls to create a control group matched on family of origin variables provides evidence that, when women with CST are compared with the matched comparison women, females who experienced CST show poorer functioning across multiple domains of parenting (sensitivity, harsh intrusiveness, boundary dissolution), but not in parenting efficacy. Follow up moderation analyses suggest that the potential effects of trauma on parenting behaviors are not attenuated by protective factors such as higher income, higher education, or stable adult relationships. Implications for interventions with childhood sexual trauma histories and directions for future study are proposed

DNA damage by lipid peroxidation products: implications in cancer, inflammation and autoimmunity

Oxidative stress and lipid peroxidation (LPO) induced by inflammation, excess metal storage and excess caloric intake cause generalized DNA damage, producing genotoxic and mutagenic effects. The consequent deregulation of cell homeostasis is implicated in the pathogenesis of a number of malignancies and degenerative diseases. Reactive aldehydes produced by LPO, such as malondialdehyde, acrolein, crotonaldehyde and 4-hydroxy-2-nonenal, react with DNA bases, generating promutagenic exocyclic DNA adducts, which likely contribute to the mutagenic and carcinogenic effects associated with oxidative stress-induced LPO. However, reactive aldehydes, when added to tumor cells, can exert an anticancerous effect. They act, analogously to other chemotherapeutic drugs, by forming DNA adducts and, in this way, they drive the tumor cells toward apoptosis. The aldehyde-DNA adducts, which can be observed during inflammation, play an important role by inducing epigenetic changes which, in turn, can modulate the inflammatory process. The pathogenic role of the adducts formed by the products of LPO with biological macromolecules in the breaking of immunological tolerance to self antigens and in the development of autoimmunity has been supported by a wealth of evidence. The instrumental role of the adducts of reactive LPO products with self protein antigens in the sensitization of autoreactive cells to the respective unmodified proteins and in the intermolecular spreading of the autoimmune responses to aldehyde-modified and native DNA is well documented. In contrast, further investigation is required in order to establish whether the formation of adducts of LPO products with DNA might incite substantial immune responsivity and might be instrumental for the spreading of the immunological responses from aldehyde-modified DNA to native DNA and similarly modified, unmodified and/or structurally analogous self protein antigens, thus leading to autoimmunity