Approximate additions and working memory in individuals with Down syndrome.
Down syndrome learners can estimate addition as well as peers when you tap their visuospatial working memory.
01Research in Context
What this study did
Belacchi et al. (2014) looked at how people with Down syndrome handle quick addition estimates. They also tested visuospatial working memory, the brain's sketch pad for pictures and space.
The team gave two number tasks. One asked which set had more dots. The other asked for a rough sum without counting. They compared the Down syndrome group to a similar group without the diagnosis.
What they found
On the dot task, the Down syndrome group scored lower. On the quick-add task, they kept up with peers. Visuospatial working memory scores predicted who would add well, but only in the Down syndrome group.
The result is mixed: one skill lags, another stays intact, and visuospatial memory links to the spared skill.
How this fits with other research
Hilton et al. (2010) studied kids with mixed intellectual disabilities. They also found that working memory tied to math success. Carmen's work narrows the link to visuospatial memory inside Down syndrome only.
Yang et al. (2016) tested exact versus approximate addition in dyslexia. Kids with dyslexia struggled with exact problems yet nailed approximations, the opposite of the Down syndrome pattern. The two studies look like a contradiction, but they test different diagnoses. Together they show that spared approximation is not universal; it depends on the condition.
Lecavalier et al. (2006) showed that Down syndrome brings clear weak spots in phonological awareness and non-word reading. Carmen adds a new profile: visuospatial memory can still support number learning even when verbal routes falter.
Why it matters
If you teach math to learners with Down syndrome, lean on visuospatial cues. Use dot arrays, number lines, and ten frames instead of word-heavy drills. Strengthen visuospatial working memory with brief spatial games before math lessons. This small shift can turn a spared skill into a teaching ally.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Open your next math session with a 2-minute spatial memory game, then teach the addition concept with dot cards instead of verbal facts.
02At a glance
03Original abstract
There is some evidence that individuals with Down syndrome (DS) may have a poorer mathematical performance and a poorer working memory (WM) than typically developing (TD) children of the same mental age. In both typical and atypical individuals, different aspects of arithmetic and their relationships with WM have been largely studied, but the specific contribution of WM to the representation and elaboration of non-symbolic quantities has received little attention. The present study examined whether individuals with DS are as capable as TD children matched for fluid intelligence of estimating numerosity both of single sets and of added sets resulting when two sequentially presented sets are added together, also considering how these tasks related to verbal and visuospatial WM. Results showed that the DS group's performance was significantly worse than the TD group's in numerosity estimation involving one set, but not when estimating the numerosity resulting from the addition. Success in the addition task was related to success in the working memory tasks, but only for the group with DS; this applied especially to the visuospatial component, which (unlike the verbal component) was not impaired in the group with DS. It is concluded that the two numerosity tasks involve different processes. It is concluded that the arithmetical and working memory difficulties of individuals with DS are not general, and they can draw on their WM resources when estimating the numerosity of additions.
Research in developmental disabilities, 2014 · doi:10.1016/j.ridd.2014.01.036