On the role of inhibition processes in mathematical disabilities / Le rôle des processus d'inhibition dans les troubles d'apprentissage de l'arithmétique

The present thesis investigates the hypothesis according to which the arithmetic retrieval deficits observed in children with math disabilities (MD) would be due to an inhibition deficit. In the first chapter, two experiments showed that children with MD (with or without reading disabilities), compared to normally-achieving children, do not present impairments in three inhibition functions (filtering, suppression, and blocking). The second chapter focused on interference in arithmetic tasks. Experiment 3 revealed that, in a multiplication verification task, children with MD were not more sensitive to interference than control children (of the same age or of the same math skills). In contrast, Experiment 4 showed that children with poor math skills were more sensitive to multiplication-related interference (i.e., the negative effect of multiplications on additions) than children with good math skills. Nevertheless, the third chapter established that the arithmetic retrieval deficits of children with MD (as well as the results of Experiment 4) can be accounted for without the recourse to inhibition. Indeed, Experiment 5 demonstrated that children with MD have poor memory representations of difficult single-digit multiplications (i.e., weak and incorrect problem-answer associations), which is sufficient to account for their retrieval deficits. Finally, in the last chapter, we considered the possibility that sensitivity to interference is involved in MD but during the development of arithmetic facts representations (not during their retrieval) and could lead to the poor representations observed in children with MD. In experiment 6, we found that counting to solve an addition might interfere with the memorization of the addition's addends (hence, with the development of problem-answer associations) but there was no evidence that children with MD are more sensitive to this interference than control children. Altogether, these data provide converging evidence against the inhibition-deficit hypothesis and suggest that ...