Numerical and area comparison abilities in Down syndrome.
"...Individuals with Down syndrome (DS) have great difficulty in learning mathematics. In recent years, research has focused on investigating whether precursors of later mathematical competence, such as estimating and comparing numerosities, are preserved in DS. Although studies have suggested a strong relationship between the ability to compare continuous quantities (e.g., area of an object) and that of comparing numerosities, it is still unknown whether this ability is preserved in DS. ..... All participants performed two eye-tracking tasks: an Area Comparison Task (ACT) and a Number Comparison Task (NCT)..... in general, the performance of the three groups was better in the ACT than in the NCT. Critically, performance of individuals with DS in both tasks was consistent with that of individuals with the same Memtal Age. The study shows that the abilities to compare area and numerosity are both preserved in DS, and that individuals with this syndrome,... show better performance in comparing area than number...."