Symbolic and nonsymbolic number comparison in children with and without dyscalculia
Résumé
Developmental dyscalculia (DD) is a pervasive difficulty affecting number processing and
arithmetic. It is encountered in around 6% of school-aged children. While previous studies
have mainly focused on general cognitive functions, the present paper aims to further
investigate the hypothesis of a specific numerical deficit in dyscalculia. The performance
of 10- and 11-year-old children with DD characterised by a weakness in arithmetic facts
retrieval and age-matched control children was compared on various number comparison
tasks. Participants were asked to compare a quantity presented in either a symbolic (Arabic
numerals, number words, canonical dots patterns) or a nonsymbolic format (noncanonical
dots patterns, and random sticks patterns) to the reference quantity 5. DD children showed
a greater numerical distance effect than control children, irrespective of the number format.
This favours a deficit in the specialised cognitive system underlying the processing
of number magnitude in children with DD. Results are discussed in terms of access and representation
deficit hypotheses.