Implicit Sequence Learning in Children With Reading Difficulties: Dyslexia Versus Low Intellectual Functioning.

Dyslexia refers to difficulties in acquiring fluent reading in the absence of an intellectual deficit. In the current study, we addressed two controversial issues surrounding this disorder. Firstly, the hypothesis of an implicit learning impairment that could contribute to the development of dyslexia, and secondly, the need to distinguish reading difficulties according to IQ, the so-called discrepancy definition between reading ability and expected ability. Of relevance, it has been suggested that implicit learning is relatively independent of IQ in comparison to explicit/strategic learning. Consequently, we compared implicit sequence learning in children (8-9 years old) with dyslexia, poor readers associated with low intellectual functioning (LIF), and typically developing children (TD). Both the Dyslexia and LIF groups learned less than the TD group. Therefore, the Dyslexia group's performance supports the hypothesis of an implicit learning deficit in this population. However, the poor learning shown by the LIF group challenges the necessity of a discrepancy definition for dyslexia (poor reading despite average IQ). This paper argues that implicit learning may influence the severity of reading difficulties rather than act as a causal factor and highlights the need for further research on the usefulness of distinguishing reading difficulties based on LIF.