Effect of Behaviour Modification Techniques on Reducing Aggression in Students with Intellectual Disability in Ogun State

This study investigates the effect of behaviour modification techniques on reducing aggressive behaviour in students with intellectual disability in special schools in Ogun State, South West Nigeria. Aggression, including physical violence, verbal outbursts, and self-injurious behaviour, is among the most challenging manifestations of intellectual disability in educational settings and places both students and staff at risk. Behaviour modification, grounded in the principles of applied behaviour analysis, employs structured reinforcement and consequence-based strategies to systematically alter targeted behaviours. Adopting a single-subject experimental design, the study monitors eight students with intellectual disability across a baseline phase and two intervention phases involving differential reinforcement of alternative behaviour and token economy systems. Behaviour frequency data are collected through systematic direct observation using interval recording. Data are graphed and analysed using visual analysis techniques consistent with single-subject methodology standards. The study also documents teacher fidelity of implementation to assess the reliability of the intervention as delivered. Findings are expected to demonstrate clear functional relationships between the behaviour modification procedures and reductions in aggressive incidents. Recommendations include embedding applied behaviour analysis competencies into in-service teacher training programmes and developing a behavioural support toolkit for special schools across South West Nigeria. The study provides practical, evidence-informed guidance for school administrators and caregivers managing aggression in students with intellectual disability. Keywords: behaviour modification, intellectual disability, aggression, Ogun State, applied behaviour analysis.