Theory of mind "beliefs", developmental characteristics and social understanding in children and adolescents with intellectual disabilities.
Kids with ID fall behind peers on false-belief tasks even when language is equal, so check cognitive predictors, not just words.
01Research in Context
What this study did
Thirion-Marissiaux et al. (2008) compared false-belief skills in kids with intellectual disability and typically developing kids matched for developmental age. They kept language comprehension the same for both groups. The team wanted to see if the ID group still lagged on theory-of-mind tasks when words were not the problem.
What they found
Even after matching language levels, the ID group scored lower on false-belief tasks. Language and different cognitive skills predicted success for each group. The gap was not just a language artefact; something else in the ID profile slows belief reasoning.
How this fits with other research
Thirion-Marissiaux et al. (2008) emotion paper looks contradictory at first. Same sample, yet emotion ToM showed a positive, age-typical pattern while the belief paper shows a deficit. The difference is the task: emotion reading stays on track, but false-belief reasoning falls behind.
Matson et al. (2004) warned us first: weak narrative language can fake a ToM deficit. The 2008 belief paper extends that by mapping which cognitive pieces matter after language is controlled.
Amorim et al. (2025) supersedes the single-diagnosis view. Across autism, ADHD and OCD, IQ and social-communication skill predict ToM better than any label, updating the 2008 ID-only conclusion.
Why it matters
Before you write a ToM goal, test both language and non-verbal mental age. If language is weak, switch to low-verbal tasks like Dahlgren et al. (2010) to avoid mistaking language limits for social-cognitive deficits. Target the specific cognitive skills the 2008 paper flags for each child, not just more false-belief drills.
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02At a glance
03Original abstract
Patterns of development of ToM belief abilities in intellectually disabled (ID) children and typically developing (TD) children matched on their developmental age were investigated. The links between cognition, language, social understanding and ToM belief abilities were examined. EDEI-R [Perron-Borelli M. (1996). Echelles Différentielles d'Efficiences Intellectuelles. Forme Révisée (EDEI-R). Paris: Editions et Applications Psychologiques.] was used to match participants and to assess social understanding. ECOSSE [Lecocq P. (1996). L'E.CO.S.SE. Une épreuve de compréhension syntaxico-sémantique. Paris: Presses Universitaires du Septentrion.] assessed the level of syntactic and semantic comprehension of French speaking, to ensure a good comprehension of the questions in false belief tasks. Five tasks assessed the ability in visual perspective taking and in understanding of false belief. A difference in the global ToM ability was found between both groups (difference hypothesis in ID participants). Specific abilities in different ToM tasks showed developmental patterns partially different and partially similar, between ID and TD groups. The interest to assess the understanding of belief by means of several tasks is confirmed. Positive links between cognition, language and ToM abilities were found in both groups, but the impact of cognition and language on abilities in each ToM task is different in both groups. Finally, the specific impact of social understanding and of chronological age on abilities in false belief in ID group is discussed.
Research in developmental disabilities, 2008 · doi:10.1016/j.ridd.2007.09.004