This multidisicplinary proposal focuses on the developmental trajectories of component cognitive abilities within inhibition and executive control functions in preschool to early school aged children living in varying levels of economic disadvantage and advantage. While many studies have shown an association between economic deprivation and impaired cognitive development in childhood, no studies have explored the impact of economic and environmental disadvantage on component neurocognitive capacities within executive control functions. We propose that 1 mechanism for the impact of poverty on cognitive development may be through delays or impaired executive control functions (e.g., working memory, inhibition) and more specifically through an impairment in inhibitory executive control functions. To explore this hypothesis, we bring 5 disciplines together--behavioral neuroscience, neuropsychology, epidemiology, child development, and economics--that represent the expertise of several actively collaborating laboratories with considerable collective experience in studying executive control functions in children and in the application of such studies to high-risk populations. The study sample takes advantage of a unique, time-limited opportunity to follow-up 2 well studied birth cohorts of children, who are from the greater New Haven area and will soon be 4 and 5 years old. We propose to characterize component cognitive abilities within inhibitory executive control functions in boys and girls from 3 income-to-need levels (below poverty, at poverty, and above poverty line) and 3 ethnicity groups (African-American, Hispanic- American and European-American) (a 2 X 3 X 3 design with 360 children total recruited at 2 ages (4 and 5 years) and followed longitudinally through age 8 years. Through growth curve modeling, we will study how these component functions are built up over the course of development from 4 to 8 years, and whether or not these trajectories vary between children growing up in poverty and environmental disadvantage and those not. We will also study how parental behavior, parental beliefs and attitudes, parental mental health, and home environment might moderate relations between economic disadvantage and possible deleterious effects on neurocognitive development. Studying inhibitory processes within executive control functions is particularly pertinent to studies of economically disadvantaged populations in whom a number of developmental delays and/or developmental disorders involving dysregulated inhibition are said to be more common. Having a more detailed understanding of the developmental trajectories of children from low-income samples on basic assessments of inhibitory executive control may inform mechanism questions about how poverty impacts general cognitive capacities.