Towards developing a more extensive construct of intellectual disability

The aim of this thesis was to re-examine the construct of intellectual disability in terms of not just what children with intellectual disability can and cannot do, but also in regards to their cognitive potential, in order to better aid their education. Children with Autism, idiopathic intellectual disability and Down syndrome were compared to typically developing children on computer based attention tasks. Overall, results showed that problem solving ability in children with intellectual disability of different etiologies is both delayed and deficient and that the Raven's Coloured Progressive Matrices is a valid means of matching children with intellectual disability to typically developing children on non-verbal mental age in experimental studies.