Michael T. Willoughby

Bio: Michael T. Willoughby is an academic researcher from Research Triangle Park. The author has contributed to research in topics: Family life & Attention deficit hyperactivity disorder. The author has an hindex of 52, co-authored 158 publications receiving 7972 citations. Previous affiliations of Michael T. Willoughby include Pennsylvania State University & RTI International.

Salivary Cortisol Mediates Effects of Poverty and Parenting on Executive Functions in Early Childhood

Abstract: In a predominantly low-income population-based longitudinal sample of 1,292 children followed from birth, higher level of salivary cortisol assessed at ages 7, 15, and 24 months was uniquely associated with lower executive function ability and to a lesser extent IQ at age 3 years. Measures of positive and negative aspects of parenting and household risk were also uniquely related to both executive functions and IQ. The effect of positive parenting on executive functions was partially mediated through cortisol. Typical or resting level of cortisol was increased in African American relative to White participants. In combination with positive and negative parenting and household risk, cortisol mediated effects of income-to-need, maternal education, and African American ethnicity on child cognitive ability.

On the Practical Interpretability of Cross-Lagged Panel Models: Rethinking a Developmental Workhorse.

Abstract: Reciprocal feedback processes between experience and development are central to contemporary developmental theory. Autoregressive cross-lagged panel (ARCL) models represent a common analytic approach intended to test such dynamics. The authors demonstrate that—despite the ARCL model's intuitive appeal—it typically (a) fails to align with the theoretical processes that it is intended to test and (b) yields estimates that are difficult to interpret meaningfully. Specifically, using a Monte Carlo simulation and two empirical examples concerning the reciprocal relation between spanking and child aggression, it is shown that the cross-lagged estimates derived from the ARCL model reflect a weighted—and typically uninterpretable—amalgam of between- and within-person associations. The authors highlight one readily implemented respecification that better addresses these multiple levels of inference.

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

Abstract: 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.

Executive function in early childhood: longitudinal measurement invariance and developmental change.

Abstract: This study tested the longitudinal measurement invariance and developmental changes of a newly developed battery of executive function (EF) tasks for use in early childhood. The battery was administered in the Family Life Project—a prospective longitudinal study (N = 1292) of families who were over-sampled from low income and African American families at the birth of a new child—at age 3, 4, and 5 year assessments. All six individual EF tasks exhibited strong measurement invariance over time. The EF battery, which was derived from the six individual tasks, exhibited partial strong invariance over time. Second-order latent growth curve models revealed individual differences in the levels but not rates of change in latent EF ability. The functional form of change was nonlinear; 60% of the total change in EF ability that was observed between the 3-5 year assessments occurred between the year 3 and 4 assessments. Results are discussed with respect to the importance of establishing scalable measures of EF ability prior to investigating experiences that predict and/or are predicted by changes in EF during early childhood.

The measurement of executive function at age 3 years: psychometric properties and criterion validity of a new battery of tasks.

Abstract: In this study, the authors examined the psychometric properties and criterion validity of a newly developed battery of tasks that were designed to assess executive function (EF) abilities in early childhood. The battery was included in the 36-month assessment of the Family Life Project (FLP), a prospective longitudinal study of 1,292 children oversampled from low-income and African American families. Ninety-one percent of children were able to complete 1 or more of the tasks. Psychometric analyses were used to test the dimensionality of each task, evaluate the item and task properties, test the dimensionality of the task battery, and evaluate the criterion validity of the battery with multi-informant measures of attention-deficit/hyperactivity disorder (ADHD) symptomatology and child performance on two subtests of the Wechsler Preschool and Primary Scale of Intelligence. Results indicated that the tasks were successful in measuring interindividual differences in child EF ability, that task scores were most informative about ability level for children in the low to moderate range of ability, that children's performance across the entire battery was adequately summarized by a single factor, and that individual differences on the EF battery were related to ADHD symptomatology and intelligence in expected ways. Results are discussed with respect to the importance of developing psychometrically sound, scalable instruments that facilitate the measurement of interindividual differences in intraindividual change of EF across the early childhood period.

Computational Tools for Probing Interactions in Multiple Linear Regression, Multilevel Modeling, and Latent Curve Analysis.

Abstract: Simple slopes, regions of significance, and confidence bands are commonly used to evaluate interactions in multiple linear regression (MLR) models, and the use of these techniques has recently been extended to multilevel or hierarchical linear modeling (HLM) and latent curve analysis (LCA). However, conducting these tests andplotting the conditional relations is often a tedious and error-prone task. This article provides an overview of methods used to probe interaction effects and describes a unified collection offreely available online resources that researchers can use to obtain significance testsforsimple slopes, compute regions of significance, and obtain confidence bands for simple slopes across the range of the moderator in the MLR, HLM, and LCA contexts. Plotting capabilities are also provided.

Beyond Diathesis Stress: Differential Susceptibility to Environmental Influences.

Abstract: Evolutionary-biological reasoning suggests that individuals should be differentially susceptible to environmental influences, with some people being not just more vulnerable than others to the negative effects of adversity, as the prevailing diathesis-stress view of psychopathology (and of many environmental influences) maintains, but also disproportionately susceptible to the beneficial effects of supportive and enriching experiences (or just the absence of adversity). Evidence consistent with the proposition that individuals differ in plasticity is reviewed. The authors document multiple instances in which (a) phenotypic temperamental characteristics, (b) endophenotypic attributes, and (c) specific genes function less like “vulnerability factors” and more like “plasticity factors,” thereby rendering some individuals more malleable or susceptible than others to both negative and positive environmental influences. Discussion focuses upon limits of the evidence, statistical criteria for distinguishing differential susceptibility from diathesis stress, potential mechanisms of influence, and unknowns in the differentialsusceptibility equation.

Human cognitive abilities: A survey of factor analytic studies

Abstract: (1998). Human cognitive abilities: A survey of factor analytic studies. Gifted and Talented International: Vol. 13, No. 2, pp. 97-98.

Education at a Glance

Abstract: A detailed review of the education sector in Australia as in the data provided by the 2006 edition of the OECD's annual publication, 'Education at a Glance' is presented. While the data has shown that in almost all OECD countries educational attainment levels are on the rise, with countries showing impressive gains in university qualifications, it also reveals that a large of share of young people still do not complete secondary school, which remains a baseline for successful entry into the labour market.