Inhibitory control is thought to demonstrate heterotypic continuity, in other words, continuity in its purpose or function but changes in its behavioral manifestation over time. This creates major methodological challenges for studying the development of inhibitory control in childhood including construct validity, developmental appropriateness and sensitivity of measures, and longitudinal factorial invariance. We meta-analyzed 198 studies using measures of inhibitory control, a key aspect of self-regulation, to estimate age ranges of usefulness for each measure. The inhibitory control measures showed limited age ranges of usefulness owing to ceiling/floor effects. Tasks were useful, on average, for a developmental span of less than 3 years. This suggests that measuring inhibitory control over longer spans of development may require use of different measures at different time points, seeking to measure heterotypic continuity. We suggest ways to study the development of inhibitory control, with overlapping measurement in a structural equation modeling framework and tests of longitudinal factorial or measurement invariance. However, as valuable as this would be for the area, we also point out that establishing longitudinal factorial invariance is neither sufficient nor necessary for examining developmental change. Any study of developmental change should be guided by theory and construct validity, aiming toward a better empirical and theoretical approach to the selection and combination of measures.

Abstract. There has been an unprecedented increase in the number of research studies employing event-related potential (ERP) techniques to examine dynamic and rapidly occurring neural processes with children during the preschool and early childhood years. Despite this, there has been relatively little discussion of the methodological and procedural differences that exist for studies of young children versus older children and adults. That is, reviewers, editors, and consumers of this work often expect developmental studies to simply apply adult techniques and procedures to younger samples. Procedurally, this creates unrealistic expectations for research paradigms, data collection, and data reduction and analyses. Scientifically, this leads to inappropriate measures and methods that hinder drawing conclusions and advancing theory. Based on ERP work with preschoolers and young children from 10 laboratories across North America, we present a summary of the most common ERP components under study in the area of emotion and cognition in young children along with 13 realistic expectations for data collection and loss, laboratory procedures and paradigms, data processing, ERP averaging, and typical challenges for conducting this type of work. This work is intended to supplement previous guidelines for work with adults and offer insights to aid researchers, reviewers, and editors in the design and evaluation of developmental research using ERPs. Here we make recommendations for researchers who plan to conduct or who are conducting ERP studies in children between ages 2 and 12 years, focusing on studies of toddlers and preschoolers. Recommendations are based on both data and our cumulative experience and include guidelines for laboratory setup, equipment and recording settings, task design, and data processing.

Research suggests that the NoGo N2 event-related potential component elicited in children during Go/NoGo and Continuous Performance tasks indexes response inhibition capacities. This meta-analysis examined what is known about the N2 component's amplitude/latency values, developmental trajectory, and the differences between amplitudes in Go and NoGo trials. Sixty-five studies measuring the N2 in children ages 2-12 were meta-analyzed to estimate the N2's average amplitude/latency at each age. Findings suggest that N2 amplitude/latency values decrease in magnitude across childhood, and NoGo N2 amplitudes were more negative than Go N2 amplitudes, supporting interpretations of this component as indexing response inhibition. Implications are discussed.

The present study considered multiple aspects of sleep in a community sample of young children (at ages 30, 36, and 42 months) and their mothers, using both diaries and actigraphy. Through principal components analysis, 17 of 20 commonly used actigraphy variables were reduced to four main components whose variables formed composites of: Activity, night-to-night Variability, Timing, and Duration. Sleep latency and daytime sleep variables remained separate from the composites. The same components were identified at each age, and for both children and mothers. Furthermore, the sleep composites derived from the components showed greater cross-age stability than individual actigraphy variables. Finally, child and mother sleep composites were related concurrently and longitudinally. These findings demonstrate a systematic and efficient way of summarizing child and mother sleep with actigraphy variables.

Background: Sleep is thought to be important for behavioral and cognitive development. However, much of the prior research on sleep's role in behavioral/cognitive development has relied upon self-report measures and crosssectional designs. Methods: The current study examined how early childhood sleep, measured actigraphically, was developmentally associated with child functioning at 54 months. Emphasis was on functioning at preschool, a crucial setting for the emergence of psychopathology. Participants included 119 children assessed longitudinally at 30, 36, 42, and 54 months. We examined correlations between child sleep and adjustment across three domains: behavioral adjustment (i.e., internalizing and externalizing problems), socioemotional skills, and academic/cognitive abilities. We further probed consistent associations with growth curve modeling. Results: Internalizing problems were associated with sleep variability, and cognitive and academic abilities were associated with sleep timing. Growth curve analysis suggested that children with more variable sleep at 30 months had higher teacher-reported internalizing problems in preschool and that children with later sleep timing at 30 months had poorer cognitive and academic skills at 54 months. However, changes in sleep from 30 to 54 months were not associated with any of the domains of adjustment. Conclusions: Findings indicate that objectively measured sleep variability and late sleep timing in toddlerhood are associated with higher levels of internalizing problems and poorer academic/cognitive abilities in preschool.

Parent-child synchrony—parent-child interaction patterns characterized by contingent social responding, mutual responsivity, and co-regulation—has been robustly associated with adaptive child outcomes. Synchrony has been investigated in both behavioral and biological frameworks. While it has been demonstrated that adversity can influence behavioral parent-child synchrony, the neural mechanisms by which this disruption occurs are understudied. The current study examined the association between adversity, parent-child behavioral synchrony, and parent-child neural synchrony across lateral prefrontal cortical regions using functional near-infrared spectroscopy hyperscanning during a parent-child interaction task that included a mild stress induction followed by a recovery period. Participants included 115 children (ages 4-5) and their primary caregivers. Parent-child behavioral synchrony was quantified as the amount time the dyad was synchronous (e.g., reciprocal communication, coordinated behaviors) during the interaction task. Parent-child neural synchrony was examined as the hemodynamic concordance between parent and child lateral PFC activation. Adversity was examined across two, empirically-derived domains: sociodemographic risk (e.g., family income) and familial risk (e.g., household chaos). Adversity, across domains, was associated with decreased parent-child behavioral synchrony across task conditions. Sociodemographic risk was associated with decreased parent-child neural synchrony in the context of experimentally-induced stress. These findings link adversity to decreased parent-child behavioral and neural synchrony.

The current study examined the association between effortful control and a well-studied neural index of self-regulation, the N2 event-related potential (ERP) component, in toddlers. Participants included 107 toddlers (44 girls) assessed at 30, 36 and 42 months of age. Participants completed a Go/NoGo task while electroencephalography data were recorded. The study focused on the N2 ERP component. Parent-reported effortful control was examined in association with the NoGo N2 ERP component. Findings suggest a positive association between the NoGo N2 component and the inhibitory control subscale of the wider effortful control dimension, suggesting that the N2 component may index processes associated with temperamental effortful control.This article is part of the theme issue 'Diverse perspectives on diversity: multi-disciplinary approaches to taxonomies of individual differences'.

Despite a robust literature examining the association between sleep problems and cognitive abilities in childhood, little is known about this association in toddlerhood, a period of rapid cognitive development. The present study examined the association between various sleep problems, using actigraphy, and performance on a standardized test of cognitive abilities, longitudinally across three ages (30, 36, and 42 months) in a large sample of toddlers (N = 493). Results revealed a between-subject effect in which the children who had more delayed sleep schedules on average also showed poorer cognitive abilities on average but did not support a within-subjects effect. Results also showed that delayed sleep explains part of the association between family socioeconomic context and child cognitive abilities.