Cognitive abilities and life experience in everyday planning in adolescents with intellectual disabilities: Support for the difference model.

Background: The literature on planning ability in individuals with intellectual disability (ID) provides no clarity on whether their ability matches their mental age (MA) or not. Perhaps can planning experience explain the mixed results. The current study investigated to what extent cognitive abilities and life experience can explain everyday planning ability in individuals with ID and to what extent results from everyday planning tasks support the developmental or the difference model of ID.
Method: Planning tests, cognitive ability tasks and a self-rated life experience form were administered to 71 adolescents with ID and 62 children with a typical development matched on MA.
Results: Adolescents with ID exhibited planning ability according to their MA. Regression analyses showed that the predictors of planning differed between the groups. The cognitive measures could predict planning in both groups, but life experience only contributed positively to planning in the MA group, whereas chronological age was negatively correlated with successful planning in the ID group.
Conclusions and Discussion: The results support the difference model of ID. When matched on MA, the individuals with ID will solve the planning task in a qualitatively different manner. Additionally, the participants with ID could not utilise their life experience when solving the planning task, contrary to the MA group. Practitioners should be aware that individuals with ID might need more everyday planning training throughout adolescence. To support adolescents with ID, practitioners may focus on supporting the individual's cognitive abilities rather than relying on their prior knowledge.
(© 2020 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.)