A Longitudinal Study of Social Cognition Development and Theory of Mind in Children With and Without Autism in South East Nigeria

This study examines the longitudinal development of social cognition and theory of mind in children with and without autism spectrum disorder in South East Nigeria, contributing original developmental trajectory data from a non-Western context. Theory of mind research has been overwhelmingly conducted in Western and East Asian samples, and whether the developmental timetable and social cognitive mechanisms apply similarly to African children, particularly those with autism, remains an open and theoretically important question. This longitudinal study followed 95 children with confirmed autism spectrum disorder and 190 matched typically developing controls from Enugu and Anambra states over three years, beginning at ages 4 to 5. Theory of mind was assessed annually using a comprehensive battery including false belief tasks, Strange Stories, and the Reading the Mind in the Eyes task adapted for Nigerian children. Executive function and language ability were assessed as theoretically specified covariates. Multilevel growth curve modelling compared developmental trajectories across groups. Results indicate that typically developing Nigerian children achieved standard theory of mind milestones at ages comparable to Western normative samples, providing cross-cultural validity evidence. Children with autism showed significantly delayed and qualitatively different theory of mind trajectories, with executive function accounting for more variance in theory of mind growth than language ability. The study has direct implications for autism assessment and intervention design in South East Nigeria. Keywords: theory of mind, social cognition, autism spectrum disorder, longitudinal study, South East Nigeria.