An Original Investigation into the Neurobiological Mechanisms Linking Early Stress Exposure to Developmental Outcomes in Nigerian Children

Early stress exposure activates neurobiological stress response systems with long-term implications for brain architecture and developmental outcomes, and investigating these mechanisms in Nigerian children living in diverse stress environments provides original evidence connecting neuroscience to early childhood education policy in Africa. This study conducted an original investigation into the neurobiological mechanisms linking early stress exposure to developmental outcomes in Nigerian children across three stress contexts: IDP displacement (Borno State), urban poverty (Lagos), and conflict-adjacent community exposure (Plateau State). A mixed biomarker and developmental assessment methodology was employed. Salivary cortisol as a stress biomarker was collected from 360 children aged 3 to 5 years (120 per site) at three time points across a school day. Developmental outcomes were assessed using the Malawi Development Assessment Tool. Parenting quality was assessed using structured observation and parent report. Structural equation modelling examined stress-development pathways with parenting quality as a moderator. Elevated cortisol reactivity was significantly associated with lower cognitive and language development scores across all three sites after controlling for age, sex, and socioeconomic status (beta = -0.38, p < 0.001). The cortisol-development relationship was significantly moderated by parenting quality, with high-quality parenting buffering 61 percent of the cortisol impact on cognitive outcomes. IDP children showed the highest mean cortisol levels. Expert review by 20 developmental neuroscience and ECD specialists confirmed the study's original methodological contribution. Recommendations include buffering-focused parenting interventions in high-stress Nigerian ECD contexts. Keywords: early stress, cortisol, neurobiological mechanisms, developmental outcomes, Nigerian children