The influence of visual stimulus properties on test performance in a nonsymbolic comparison task

The validity of nonsymbolic comparison tasks has been a point of discussion (De Smedt et al., 2013). It has been suggested that visual parameters might influence the relationship between approximate number system (ANS) and math. Most researchers have therefore attempted to control for visual parameters when measuring ANS, such as dot size, density and surface array. However, it was argued recently that this method is insufficient, because adults tend to integrate multiple visual cues when judging number (Gebuis & Reynvoet, 2012). With that in mind, no special mechanism could exist (ANS) that processes nonsymbolic number independently of visual cues. This finding challenges the validity of existing nonsymbolic (dot) comparison tasks. Therefore, the current study examined to what extent (an integration of) visual cues has an influence on test performance on a nonsymbolic task in children from grade 1 through 4 (6 to 10 years of age).