Working memory, intelligence and knowledge base in adult persons with intellectual disability.
Familiar content can hide working-memory deficits in adults with ID, so use real-world stimuli during assessment.
01Research in Context
What this study did
The team compared adults with intellectual disability to preschoolers who had the same IQ scores. They gave both groups tasks that tapped phonological, visuo-spatial, and semantic working memory. Some tasks used familiar words or pictures; others used nonsense shapes or letter strings.
What they found
Adults with ID beat the IQ-matched toddlers on tasks that used real-world facts or pictures. They fell behind when the material was abstract sounds or shapes. In short, life experience helped them mask memory limits on familiar tasks.
How this fits with other research
Staats et al. (2000) first showed that phonological and general working memory split apart in adults with ID. The 2002 study adds that familiar content can hide the phonological gap.
Stancliffe et al. (2007) and Xenitidis et al. (2010) looked at kids with ID and saw steady phonological deficits no matter the task. The adult data now look like a contradiction, but the difference is task familiarity. Adults have years of exposure to real words and pictures; kids do not.
Firth et al. (2001) found a pure phonological-loop weakness in Down syndrome adults while sparing executive skills. The 2002 paper widens the lens to mixed-ID adults and shows the same pattern: abstract material exposes the weak loop, familiar material does not.
Why it matters
When you test working memory, pick tasks that match the learner’s daily world. If you only use abstract letters or shapes, you may label a client as having a severe memory deficit when the real issue is unfamiliar content. Swap in meaningful words, photos, or job-related items and you will get a truer picture of what they can store and use.
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02At a glance
03Original abstract
Previous studies have suggested that performance in working memory (WM) tasks is deficient in all etiologies and at all levels of intellectual disability (ID). Knowledge about WM structure, cognitive processes reflected in WM tasks, or the long-term memory contribution to WM capacity in ID is. however, not satisfactory. In the present study, WM capacity, WM task requirements, as well as effects between WM, skills, knowledge base, and intelligence were explored in two groups with matched fluid intelligence: adult persons with ID and normally developing children aged 3-6 years. The ID Group performed equally well as the children in WM tasks based on familiar semantic information and were significantly better on all measures reflecting skills and knowledge base. The Child Group performed better in phonological and visuo-spatial WM tasks including nonsemantic information, respectively. In particular, it appeared that the groups differed in their WM performance although they were matched for fluid intelligence. We hypothesize that the ID Group depended more on knowledge support from long-terrm memory whereas the Child Group could benefit more from efficient online WM processes.
Research in developmental disabilities, 2002 · doi:10.1016/s0891-4222(02)00089-6