Dyslexic children show deficits in implicit sequence learning, but not in explicit sequence learning or contextual cueing

Abstract

Dyslexia is a specific learning disability characterized by difficulties with accurate and/or fluent word recognition and by poor spelling abilities. The absence of other high level cognitive deficits in the dyslexic population has led some authors to propose that non-strategical processes like implicit learning could be impaired in this population. Most studies have addressed this issue by using sequence learning tasks, but so far the results have not been conclusive. We test this hypothesis by comparing the performance of dyslexic children and good readers in both implicit and explicit versions of the sequence learning task, as well as in another implicit learning task not involving sequential information. The results showed that dyslexic children failed to learn the sequence when they were not informed about its presence (implicit condition). In contrast, they learned without significant differences in relation to the good readers group when they were encouraged to discover the sequence and to use it in order to improve their performance (explicit condition). Moreover, we observed that this implicit learning deficit was not extended to other forms of non-sequential, implicit learning such as contextual cueing. In this case, both groups showed similar implicit learning about the information provided by the visual context. These results help to clarify previous contradictory data, and they are discussed in relation to how the implicit sequence learning deficit could contribute to the understanding of dyslexia.

Impaired implicit sequence learning in children with developmental dyslexia

“…The results are in line with previous studies reporting implicit sequence learning impairments in children (Jimenez-Fernandez et al, 2011;Vicari et al, 2003Vicari et al, , 2005 and adults (Du & Kelly, 2013;Howard et al, 2006;Menghini et al, 2006;Stoodley et al, 2006) with DD. They extend previous findings by showing, for the first time, that the sequence learning impairment in children with DD may be most pronounced in learning stages beyond a single practice session and the early, fast acquisition phase.…”

Investigating implicit statistical learning mechanisms through contextual cueing

“…CC is not confined to humans because similar CC effects have been reported in baboons [21] and pigeons [24]. CC has also been shown to be independent of IQ [25], and to remain intact in numerous psychological and neurological diseases, such as schizophrenia [26], dyslexia [27,28], autistic spectrum disorder [29,30], and even Korsarkoff's syndrome [31]. CC is nonetheless strongly impaired in Parkinson's [32] and depressed patients [26].…”

Linking memory and language: Evidence for a serial-order learning impairment in dyslexia

“…Crucially, only the latter task involved memory for serial-order. People with dyslexia showed impaired SRT sequence learning but unimpaired spatial context learning (see also Jiménez-Fernández, Vaquero, Jiménez, & Defior, 2011). Serial-order learning in dyslexia phonological theory of dyslexia (Stanovich, 1988;Snowling, 2000).…”