A Longitudinal Investigation of Conflict and Delay Inhibitory Control in Toddlers and Preschoolers

Assessing anxiety problems in a community sample during toddlerhood: The impact of child temperament and maternal intrusiveness

Previous research indicates that child temperament and maternal behaviors are related to internalizing behaviors in children. We assessed whether maternal intrusiveness (MI) observed at 10-months would moderate the impact of temperamental fear and the impact of inhibitory control (IC) at 24 months on anxiety problems at 36 months. A mother-child interaction task was coded for MI. Behavioral tasks were given to assess children's IC. Parents completed questionnaires about their children's temperamental fear and anxiety problems. Results showed that greater temperamental fear reported at 24 months predicted greater anxiety problems reported at 36 months, regardless of MI levels. Lower levels of IC at 24 months predicted more anxiety problems reported at 36 months when children experienced greater MI. These findings illustrate the importance of examining both intrinsic and extrinsic factors, independently and interactively, that contribute to children's anxiety problems in toddlerhood.

Predictors of executive function among 2 year olds from a Thai birth cohort

Executive function (EF) is a critical skill for academic achievement. Research on the psychosocial and environmental predictors of EF, particularly among Southeast Asian, agricultural, and low income/rural populations, is limited. Our longitudinal study explored the influence of agricultural environmental, psychosocial, and temperamental factors on children's emerging EF. Three-hundred and nine farm worker women were recruited during the first trimester of pregnancy. We evaluated the effects of prenatal insecticide exposure and psychosocial factors on "cool" (i.e., cognitive: A-not-B task, looking version) and "hot" EF (i.e., affective, response inhibition) measures of emerging EF. Maternal urine samples were collected monthly during pregnancy, composited, and analyzed for dialkylphosphate (DAP) metabolites of organophosphate insecticides. Psychosocial factors included socioeconomic status, maternal psychological factors, and quality of mother-child behavioral interactions. Backward stepwise regressions evaluated predictors of children's EF at 12 (N = 288), 18 (N = 277) and 24 (N = 280) months of age. We observed different predictive models for cool EF, as measured by A-not-B task, vs. hot EF, as measured by response inhibition tasks. Report of housing quality as a surrogate for income was a significant predictor of emerging EF. However, these variables had opposite effects for cool vs. hot EF. More financial resources predicted better cool EF performance but poorer hot EF performance. Qualitative findings indicate that homes with fewer resources were in tribal areas where children must remain close to an adult for safety reasons. This finding suggests that challenging physical environments (e.g., an elevated bamboo home with no electricity or running water), may contribute to development of higher levels of response inhibition through parental socialization methods that emphasize compliance. Children who tended to show more arousal and excitability, and joy reactivity as young infants in the laboratory setting had better cognitive performance. In contrast, maternal emotional availability was a significant predictor of hot EF. As expected, increased maternal exposure to pesticides during pregnancy was associated with worse cognitive performance but was not associated with inhibitory control. Identifying risk factors contributing to the differential developmental pathways of cool and hot EF will inform prevention strategies to promote healthy development in this and other unstudied rural, low income Southeast Asian farming communities.

From terrible twos to sassy sixes: The development of vocabulary and executive functioning across early childhood

Across the early childhood period of development, young children exhibit considerable growth in their executive functioning (EF) and vocabulary abilities. Understanding the developmental trajectory of these seemingly interrelated processes is important as both early vocabulary and EF have been shown to predict critical academic and socio-emotional outcomes later in childhood. Although previous research suggests that EF and vocabulary are correlated in early childhood, much of the existing longitudinal research has focused on unidirectional relations among preschool child samples. The current large-scale study, therefore, sought to examine whether children's vocabulary and EF abilities are bidirectionally related over time across four measurement waves in early childhood (i.e., at ages 2, 3, 4, and 6). At each timepoint, children's vocabulary skills were positively correlated with their concurrent EF abilities. After controlling for child sex and maternal education status, the best-fitting, cross-lagged panel model was a unidirectional model whereby children's early vocabulary scores predicted their later EF performance at each timepoint. Although age 2 EF significantly predicted age 3 vocabulary size, this association was no longer significant after accounting for maternal education status. Our results illustrate that vocabulary size plays an important role in predicting children's later EF performance across various timepoints in early childhood, even after controlling for children's initial EF scores. These findings have important implications for intervention research as fostering early vocabulary acquisition may serve as a possible avenue for improving EF outcomes in young children. RESEARCH HIGHLIGHTS: Children's vocabulary size is positively correlated with their concurrent executive functioning skill at ages 2, 3, 4, and 6 Young children's early vocabulary scores predict their later EF performance across measurement waves, even after controlling for initial EF skill There is stability in children's relative vocabulary size and executive functioning performance over time in early childhood.

ADHD and ASD symptoms in young males with fragile X syndrome: associations with early trajectories of inhibitory control

Inhibitory control (IC), the ability to suppress inappropriate responses, emerges late in the first year of life and improves across typical development, concurrent with brain maturation. The development of IC is critical to various social-emotional and behavioral functions, with IC difficulties being linked to numerous neurodevelopmental disorders, including attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Fragile X syndrome (FXS) is a single-gene disorder characterized by IC difficulties, and elevated rates of ADHD and ASD, making it a useful model for understanding the early development and consequences of IC. In this longitudinal study, we characterized IC trajectories across multiple time points between 16 and 71 months of age in young males with FXS (n = 79) relative to neurotypical (NT) controls (n=49). To explore the association between behavioral outcomes and IC, we identified a subsample of 50 children with longitudinal IC data and an outcome assessment for ADHD and ASD symptoms at age 5 (FXS: n = 26, NT: n = 24). Results indicated that, compared to their NT peers, young males with FXS exhibit differences in IC as early as 24 months, with group differences increasing through age 5. Additionally, we determined that lower IC levels at 24 months were associated with later ADHD symptoms and a decreasing slope in IC over time was associated with later ASD symptoms in male children with FXS. These findings help refine early developmental phenotypes of FXS and highlight IC as a potential target for early detection and intervention of ASD and ADHD symptoms in male children with FXS.

The Interplay between Socioeconomic Status, Parenting and Temperament Predicts Inhibitory Control at Two Years of Age

This paper investigates the interplay between environmental factors (socioeconomic status (SES) and parenting) and temperament in the development of inhibitory control (IC) at 2 years of age. We administered to toddlers (n = 59) a delay of gratification task which measures IC in the context of self-regulation. Parents reported their toddlers' temperament, parenting strategies, and SES. We hypothesized that poorer IC would be associated with more reactive temperament, less effortful control, lower SES and inconsistent/coercive parenting practices. Finally, we explored the interaction between temperament, parenting and SES. We found that both coercive parenting and low-SES were negatively correlated to IC at the age of 2 years. Temperamental reactivity was unrelated to IC, whereas temperamental effortful control (EC) was positively associated with IC. Results revealed a moderation effect of EC on the influence of coercive parenting and SES in toddlers' IC. Toddlers from lower SES backgrounds and with lower EC were more affected by inconsistent/coercive parenting practices and showed the poorest IC. In contrast, toddlers exhibiting high and average levels of EC seemed to be protected from the detrimental effect of low-SES and inconsistent/coercive parenting on IC. These results suggest that strengthening toddlers' EC and improving parents' parenting skills might be especially relevant for the development of IC in the context of self-regulation, particularly by preventing self-regulatory problems in children from socioeconomically deprived environments. Future studies with larger samples, focusing on populations from severe socioeconomically deprived environments, or intervention studies will be needed in order to confirm and expand our findings.

Universality and context-specificity in early executive function development

A renewed interest in early executive function (i.e., EF or the conscious control of thought and behavior) development has led several research groups to suggest that EF may be emerging and is less coordinated (e.g., showing few relations between tasks) in the first few years (Devine et al., 2019; Gago Galvagno et al., 2021; Johansson et al., 2016; Miller & Marcovitch, 2015; Ribner et al., 2022). This potentially universal development in EF does not exclude the possibility that EF may also differ across context (e.g., Gago Galvagno et al., 2021; Lohndorf et al., 2019; Tran et al., 2015) reflecting unique strengths and development built within one's sociocultural environment. The present paper explores potential universal and context-specific early EF developments by focusing on three aims: (1) reviewing work on EF within the first two years of life that may speak to potential universality in the measurement, structure, growth, stability, and conceptualization of early EF (2) reviewing research that may speak to how the sociocultural context may play a role in context-specific development within early EF and (3) examining potential developmental EF frameworks for understanding universal and context-specific developments of early EF within context.

Predicting behavioral and brain markers of inhibitory control at preschool age from early measures of executive attention

Background

Inhibitory control (IC) is the ability to prevent prepotent responses when inappropriate. Longitudinal research on IC development has mainly focused on early childhood and adolescence, while research on IC development in the first years of life is still scarce. To address this gap in the literature, we explored the association between executive attention (EA) and elementary forms of IC in infancy and toddlerhood, with individual differences in IC later at 5 years of age.

Method

We conducted a five-wave longitudinal study in which children's EA and IC (n = 96) were tested at the age of 9 and 16 months and 2, 3, and 5 years. Children performed various age-appropriate EA and IC tasks in each wave, measuring inhibition of attention, endogenous control of attention, inhibition of the response, and conflict inhibition. At 5 years of age, IC was measured with a Go/No-go task while recording event-related potentials. After correlation analyses, structural equation model analyses were performed to predict IC at 5 years of age from EA and early IC measures.

Results

The results revealed that EA at 9 months predicted IC measures at 2 years of age. Likewise, measures of IC at 2 years predicted performance on the Go/No-go task at behavioral and neural levels. No direct association was found between EA at 9 months and IC at 5 years of age. We further observed that some EA and IC measures were not associated across time.

Conclusion

As we expected, EA skills in infancy and toddlerhood were related to better performance of children on IC tasks, toghether with a more mature inhibition-related brain functioning. Altogether, the results indicate that IC in early childhood could be predicted from EA and IC at 9 months and 2 years of age and suggest that the early emergence of IC relies on the development of particular EA and basic IC skills. However, some discontinuities in the longitudinal development of IC are observed in the first 5 years of life. These findings provide further support for the hierarchical model of IC development.

Using the Flanker Task to Examine Genetic and Environmental Contributions in Inhibitory Control Across the Preschool Period

The limited research exploring genetic and environmental influences on inhibitory control (IC) in preschoolers has relied on parent ratings or simple delay tasks and has produced mixed results. The present study uses a cognitively-challenging Flanker task to examine genetic and environmental contributions to the development of early IC in a longitudinal sample of 310 same-sex twin pairs (123 MZ; 187 DZ; 51% female) assessed at ages 3, 4 and 5 years. IC was significantly heritable at each age (a²: age 3 = .36; age 4 = .36; age 5 = .35). Stability was entirely accounted for by genetic influences, and change was explained by genetic and nonshared environmental factors. No significant shared environmental influences were observed.

Vocabulary and Executive Functioning: A Scoping Review of the Unidirectional and Bidirectional Associations across Early Childhood

Early childhood marks a time where word learning is accompanied by rapid growth in the cognitive processes that underlie self-modulated and goal-directed behavior (i.e., executive functions). Although there is empirical evidence to support the association between executive functioning and vocabulary in childhood, inconsistent findings have been reported regarding the extent to which early executive functioning abilities predict later vocabulary outcomes and vice versa. To clarify the nature of the longitudinal relation between these two processes and to examine what, if any, claims can be made about their interdependence, a critical review of the literature was conducted. Also addressed are the conceptual and/or methodological differences that exist across studies conducted on this topic that may be contributing to some of the discrepancies reported in the longitudinal literature. Finally, this review provides practical and empirically informed future directions to serve as a resource for early childhood researchers advancing this area of study.

Conducting Virtual Assessments in Developmental Research: COVID-19 Restrictions as a Case Example

Developmental researchers face considerable challenges regarding maximizing data collection and reducing participant attrition. In this article, we use our experiences implementing our study on the effects of timing of prenatal stress on maternal and infant outcomes during the COVID-19 pandemic as a framework to discuss the difficulties and solutions for these challenges, including the development of two types of virtual assessments. Specific information regarding use of virtual platforms, confidentiality, engaging children during video conferencing, and modifying the major assessments of our research are discussed. Feasibility data are presented, and data analytic challenges regarding statistical inference are outlined. Finally, we conclude with some of the unintended positive consequences for our research that resulted from making these modifications to our original methods.

Heterotypic continuity of inhibitory control in early childhood: Evidence from four widely used measures

Inhibitory control has been widely studied in association with social and academic adjustment. However, prior studies have generally overlooked the potential heterotypic continuity of inhibitory control and how this could affect assessment and understanding of its development. In the present study, we systematically considered heterotypic continuity in four well-established measures of inhibitory control, testing two competing hypotheses: (a) the manifestation of inhibitory control coheres within and across time in consistent, relatively simple ways, consistent with homotypic continuity. Alternatively, (b) with developmental growth, inhibitory control manifests in more complex ways with changes across development, consistent with heterotypic continuity. We also explored differences in inhibitory control as a function of the child's sex, language ability, and the family's socioeconomic status. Children (N = 513) were studied longitudinally at 30, 36, and 42 months of age. Changes in the patterns of associations within and among inhibitory control measures across ages suggest that the measures' meanings change with age, the construct manifests differently across development, and, therefore, that the construct shows heterotypic continuity. We argue that the heterotypic continuity of inhibitory control motivates the use of different combinations of inhibitory control indexes at different points in development in future research to improve validity. Confirmatory factors and growth curves also suggest that individual differences in inhibitory control endure, with convergence among inhibitory control measures by 36 months of age. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Inhibitory Dimensions and Delay of Gratification: A Comparative Study on Individuals with Down Syndrome and Typically Developing Children

While previous research on inhibition in people with Down syndrome (DS) reported contradictory results, with no explicit theoretical model, on the other hand, a more homogeneous impaired profile on the delay of gratification skills emerged. The main goal of the present study was to investigate response inhibition, interference suppression, and delay of gratification in 51 individuals with DS matched for a measure of mental age (MA) with 71 typically developing (TD) children. Moreover, we cross-sectionally explored the strengths and weaknesses of these components in children and adolescents vs. adults with DS with the same MA. A battery of laboratory tasks tapping on inhibitory sub-components and delay of gratification was administrated. Results indicated that individuals with DS showed an overall worse performance compared to TD children on response inhibition and delay of gratification, while no differences emerged between the two samples on the interference suppression. Additionally, our results suggested that older individuals with DS outperformed the younger ones both in response inhibition and in the delay of gratification, whereas the interference suppression still remains impaired in adulthood. This study highlights the importance of evaluating inhibitory sub-components considering both MA and chronological age in order to promote more effective and evidence-based training for this population.

Understanding the Emergence of Social Anxiety in Children With Behavioral Inhibition

Behavioral inhibition (BI) is a temperament characterized in early childhood by distress to novelty and avoidance of unfamiliar people, and it is one of the best-known risk factors for the development of social anxiety. However, nearly 60% of children with BI do not go on to meet criteria for social anxiety disorder. In this review we present an approach to understanding differential developmental trajectories among children with BI. We review research using laboratory-based tasks that isolate specific attention processes that enhance versus mitigate risk for social anxiety among behaviorally inhibited children and studies that suggest that BI is associated with heightened detection of novelty or threat. Moreover, stimulus-driven control processes, which we term "automatic control," increase the probability that behaviorally inhibited children display socially reticent behavior and develop social anxiety. In contrast, goal-driven control processes, which we term "planful control," decrease risk for anxiety. We suggest that these three categories of processes (detection, automatic control, and planful control) function together to determine whether behaviorally inhibited children are able to flexibly regulate their initial reactions to novelty, and in turn, decrease risk for social anxiety. Although laboratory-based tasks have identified these processes underlying risk and resilience, the challenge is linking them to the emotions, thoughts, and behaviors of behaviorally inhibited children in real-world contexts.

The relationship between temperamental dimensions and inhibitory control in early childhood: Implications for language acquisition

The present study investigates the latent organization of inhibitory control in children aged between 2;3 and 3;0 years. In addition, it explores the relationships between temperament dimensions - social orientation, motor activity, and attention -, inhibitory control and language. One-hundred-twelve typically developing children were evaluated with tasks for inhibitory control and lexical skills, while ratings of temperament and language were collected from their caregivers. A Confirmatory Factor Analysis reveals that inhibitory control seems to be best described by a unitary dimension. A Structural Equation Model suggests that 78 % of the variance in vocabulary is explained by a model considering the language observed measures, the three temperamental dimensions, and inhibitory control and in which both temperamental attention and the latent dimension of inhibitory control are significantly related to vocabulary. In addition, inhibitory control does not mediate the relationship between temperament and language.

Inclusion of a Mixed Condition Makes the Day/Night Task More Analogous to the Adult Stroop

In a study with 4-year-old children, we added a mixed condition to the traditional day/night task to examine performance and response times for congruent and incongruent trials within the same condition. There were no differences in percentage correct performance between the incongruent and mixed conditions; however, children performed best on the congruent condition. EEG recordings showed differential patterns of frontal power and coherence suggesting increasing cognitive load from congruent to incongruent to mixed conditions. Our pattern of findings suggest that the mixed condition of the day/night Stroop task is a more appropriate child equivalent to the adult color-word Stroop task.