In a paper recently published in Cortex, Jan Lonnemann (RWTH Aachen University, Germany) and colleagues report that many children at the age of 8-9 years seem to represent numbers spatially. Interestingly, boys using this kind of representation tended to have better calculation abilities, while girls who represent numbers spatially tended to show poorer calculation abilities.

The authors assume that these differences may be due to gender-specific thinking styles: for boys, who may prefer visual-spatial thinking styles, it seems to be helpful to represent numbers spatially when being confronted with calculation problems, whereas for girls preferring verbal thinking styles it may be even detrimental.

Evidence for a connection between number and space processing comes from behavioral, patient, and brain imaging data, but only a few studies have addressed this issue in children.

In this study, the Authors asked children (n=118) at the age of 8–9 years to decide which one of the two numerical distances in a visually presented number triplet was numerically larger. Numerical and spatial distances were manipulated independently, resulting in congruent, neutral, and incongruent conditions.

The spatial distances between the numbers clearly affected the comparison of numerical distances: reactions times were faster and error rates smaller for congruent than for incongruent trials. These findings are in line with the assumption of a spatial layout of mental number representations in third graders. Correlations between the size of the congruity effect and calculation abilities were found to be differently marked for girls and boys: a positive correlation was found for boys, while a marginally negative correlation was obtained for girls.

Article: Lonnemann J, Krinzinger H, Knops and Willmes K: Spatial representations of numbers in children and their connection with calculation abilities. Cortex 2008;44:420–428.