Longitudinal Effects of Early Adversity on Executive Function Development in Nigerian Children: Evidence from Osun State

This study examines the longitudinal relationship between early adversity exposure and executive function development in children from Osun State, South West Nigeria. Executive functions, encompassing working memory, cognitive flexibility, and inhibitory control, are critical for academic success and self-regulation, and evidence from high-income countries suggests that early adversity significantly undermines their development. However, longitudinal data from low and middle-income country contexts remain sparse. This study followed 280 children from age 3 through age 7 using a cohort design, assessing adversity exposure through the Adverse Childhood Experiences scale at baseline and executive function development biennially using the Developmental Neuropsychological Assessment. Multiple regression and latent growth curve modelling were applied to identify trajectories and predictors. Results indicate that cumulative adversity significantly predicted slower executive function growth trajectories, with poverty and household instability exerting the strongest independent effects. Notably, the presence of a responsive caregiver partially mitigated adversity-related executive function deficits, suggesting the buffering role of relational security. The study fills a critical gap in developmental psychology research by providing longitudinal evidence from a Nigerian context and demonstrating that adversity effects on executive function are not deterministic when protective relational factors are present. Recommendations focus on early intervention programmes targeting adversity-exposed families in Osun State. Keywords: early adversity, executive function, longitudinal study, Osun State, children.