Developmental Trajectories of Executive Function From Preschool to Middle Childhood in Low-Income Nigerian Households: A Longitudinal Study

This study maps developmental trajectories of executive function from preschool to middle childhood in children from low-income households in Nigeria, using a longitudinal design spanning five years across cohorts in Kano, Enugu, and Lagos states. Executive function development during this age window is predictive of academic readiness, social adjustment, and long-term life outcomes, yet virtually no longitudinal developmental trajectory data exist from Nigerian or West African samples. A sample of 480 children aged 3 to 4 years at baseline was assessed biennially through age 8 using a comprehensive executive function battery covering inhibitory control, working memory, and cognitive flexibility. Growth curve modelling identified distinct developmental trajectories, while multilevel regression examined household, caregiver, and intervention variables as trajectory predictors. Three executive function growth trajectories were identified: high-stable, moderate-accelerating, and low-delayed. Household income mobility and caregiver responsiveness predicted trajectory membership more strongly than baseline socioeconomic status, suggesting that dynamic environmental change matters more than static poverty classification. Children in communities with access to quality early childhood programmes demonstrated higher probabilities of joining the high-stable and moderate-accelerating trajectories. The study constitutes a foundational longitudinal contribution to developmental psychology in sub-Saharan Africa and provides critical trajectory evidence for the design of early childhood policies across Nigeria. Keywords: executive function, developmental trajectories, longitudinal study, low-income households, Nigeria.