Both specific and general cognitive factors account for dyscalculia.

Noël, Marie-Pascale [UCL] Rousselle, Laurence [UCL] De Visscher, Alice [UCL]

Developmental dyscalculia (DD) is a persistent and specific disorder of numerical development and mathematics learning, which cannot be the direct consequence of a mental retardation, inadequate education or sensory deficit (see DSM IV, American Psychiatric Association, 1994). The difficulties encountered by people with DD are varied; they can concern the mastery of the symbolic number systems (permitting one to read and write Arabic numbers and to understand the base-10 system), the storage of arithmetic facts in long-term memory (for example, remembering that 5 + 4 = 9 or 8 x 3 = 24), or the achievement of calculation procedures or problem solving. Currently, various proposals are made to account for these difficulties. Some assume the existence of a basic number deficit; others emphasize the role of general cognitive factors. In this paper, we will develop one hypothesis for each of these two types of proposals..