Deficits in numerical magnitude perception characterize the mathematics learning disability developmental dyscalculia (DD), but recent studies suggest the relation stems from inhibitory control demands from incongruent visual cues in the nonsymbolic number comparison task. This study investigated the relation among magnitude perception during…

Many children have significant mathematical learning disabilities (MLD, or dyscalculia) despite adequate schooling. The current study hypothesizes that MLD partly results from a deficiency in the Approximate Number System (ANS) that supports nonverbal numerical representations across species and throughout development. In this study of 71 ninth…

Two studies sought to determine the developmental relationship between the child's use of counting as a notational symbol system to extract, compare, and reproduce numerical information and the development of number conservation. Subjects were four- to six-year-old children in Study 1 and seven- to nine-year-old learning disabled children in Study…