Implicit memory is independent from IQ and age but not from etiology: evidence from Down and Williams syndromes.
Down syndrome keeps implicit pattern learning; Williams syndrome loses it—plan your teaching methods accordingly.
01Research in Context
What this study did
The team tested kids and adults with Down syndrome and Williams syndrome on a serial-reaction-time game. Players pressed buttons as fast as they could when lights popped up. Some light patterns repeated, so the game secretly measured how much they learned the sequence without being told.
Typical kids of the same mental age played the same game. The study wanted to know if implicit learning stayed strong even when IQ and age were low.
What they found
Down syndrome learners picked up the hidden pattern just as well as mental-age peers. Williams syndrome learners did not; their reaction times never sped up on the repeating sequence.
IQ and age did not predict who learned the pattern. The genetic syndrome did.
How this fits with other research
de Graaf et al. (2011) ran almost the same game and got the same Down syndrome result, but added fragile X. Together the two papers show that preserved procedural learning is not unique to Down syndrome, yet it is not guaranteed across all genetic conditions.
Johns et al. (2012) switched the task to smell memory and still found spared implicit memory in Down syndrome. The pattern holds across very different senses and tests.
Micai et al. (2021) meta-analysis looks like a contradiction: it says Down syndrome has clear cognitive deficits. The key difference is domain. Inhibition is weak, but implicit sequence learning is intact. Expect trouble with self-control, not with picking up routines.
Gofer-Levi et al. (2013) found implicit motor-sequence problems in cerebral palsy, matching the Williams syndrome deficit. Multiple etiologies can hit the same learning loop.
Why it matters
If you work with Williams syndrome, do not assume repeated practice alone will teach keyboarding, dance steps, or assembly routines. Add extra cues, break sequences into short chunks, and check for learning after each chunk. With Down syndrome, feel confident using consistent routines; they will catch the pattern even if their IQ scores are low. Match the support to the syndrome, not to the IQ number.
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Join Free →Test a short three-step motor routine with a Williams learner; if no speed gain after two blocks, add picture cues and explicit instruction.
02At a glance
03Original abstract
BACKGROUND: In the last few years, experimental data have been reported on differences in implicit memory processes of genetically distinct groups of individuals with Intellectual Disability (ID). These evidences are relevant for the more general debate on supposed asynchrony of cognitive maturation in children with abnormal brain development. This study, comparing implicit memory processes in individuals with Williams syndrome (WS) and Down syndrome (DS), was planned to verify the 'etiological specificity' hypotheses pertaining to the skill learning abilities of individuals with ID. METHOD: A modified version of Nissen and Bullemer's (1987) Serial Reaction Time (SRT) task was used. The performances of three group were evaluated. The first group consisted of thirty-two people with WS (18 males and 14 females). The second group was comprised of twenty-six individuals with DS (14 males and 12 females). The two groups of individuals with ID were selected so that the groups were comparable as for mental age and chronological age. The third group consisted of forty-nine typically developed children with a mental age similar to that of the groups with WS and DS. RESULTS: The two groups of individuals with ID demonstrated different patterns of procedural learning. WS individuals revealed poor implicit learning of the temporal sequence of events characterizing the ordered blocks in the SRT task. Indeed, differently from normal controls, WS participants showed no reaction time (RT) speeding through ordered blocks. Most importantly, the rebound effect, which so dramatically affected normal children's RTs passing from the last ordered to the last block, had only a marginal influence on WS children's RTs. Differently from the WS group, the rate of procedural learning of the participants with DS was comparable to that of their controls. Indeed, DS and typically developed individuals showed parallel RT variations in the series of ordered blocks and, more importantly, passing from the last ordered to the last block. Therefore, a substantial preservation of skill learning abilities in this genetic syndrome is confirmed. CONCLUSIONS: The results of the present study document that procedural learning in individuals with ID depends on the aetiology of the syndrome, thus supporting the etiological specificity account of their cognitive development. These results are relevant for our knowledge about the qualitative aspects and the underlying neurobiological substrate of the anomalous cognitive development in mentally retarded people.
Journal of intellectual disability research : JIDR, 2007 · doi:10.1111/j.1365-2788.2007.01003.x