Behavioral studies in normal developing children from the age of 6 (Romain Mathieu – Laboratoire DECOPSY, Pr Pierre Barrouillet), in children with dyscalculia (Jeanne Bagnoud et Sandrine Masson – Service Escale, Dr Isabelle Poirot), in young adults and in older adults (Jasinta Dewi-Freitag).
Through the the collect of solution times, we infer the stratégies used by children in adults when they solve simple addition problems. The results of these studies allowed us to question the dominant model of the litterature according to which the answer to simple problems are retrieved from long-term memory. We rather suggest that simple problems such as 3 + 2 are solved by unscounscious counting procedures by expert arithmeticians. In order to test our hypothesis, we also conduct a large series of study to investigate the effect of intensive training on addition solution times. To do so, we use an alphabet numerical task (C + 3 = ?) wherein adults are in conditions that are close to their first acquisition of more natural calculations (2 + 3 = ?). This line of research could help us to put forward a new model concerning the explication of dyscalculia.