Spatial representations of numbers and letters in children

Marcus Hasselhorn,Telse Nagler,Jan Lonnemann,Sven Lindberg,Janosch Linkersdörfer

doi:10.3389/fpsyg.2013.00544

Abstract

Different lines of evidence suggest that children's mental representations of numbers are spatially organized in form of a mental number line. It is, however, still unclear whether a spatial organization is specific for the numerical domain or also applies to other ordinal sequences in children. In the present study, children (n = 129) aged 8–9 years were asked to indicate the midpoint of lines flanked by task-irrelevant digits or letters. We found that the localization of the midpoint was systematically biased toward the larger digit. A similar, but less pronounced, effect was detected for letters with spatial biases toward the letter succeeding in the alphabet. Instead of assuming domain-specific forms of spatial representations, we suggest that ordinal information expressing relations between different items of a sequence might be spatially coded in children, whereby numbers seem to convey this kind of information in the most salient way.

Highlights

Evidence for an association between number and space processing comes from behavioral experiments, patient examinations, and functional brain imaging studies
Instead of assuming domain-specific forms of spatial representations, we suggest that ordinal information expressing relations between different items of a sequence might be spatially coded in children, whereby numbers seem to convey this kind of information in the most salient way
The present study, revealed a similar effect for letters with bias toward the letter succeeding in the alphabet, indicating www.frontiersin.org that a spontaneous spatial coding of information is not specific for the numerical domain

Summary

Introduction

Evidence for an association between number and space processing comes from behavioral experiments, patient examinations, and functional brain imaging studies (see Hubbard et al, 2005 for an overview). First indications of numerical-spatial interactions in children were presented by Berch et al (1999), who demonstrated that typically developing children at the age of 9 years exhibited the so-called SNARC effect (Spatial Numerical Association of Response Codes; Dehaene et al, 1993). This effect reflects the observation that people respond faster with the lefthand side to smaller numbers than to larger numbers and vice versa for the right-hand side when being asked to compare numbers with respect to their magnitude or to classify numbers as even or odd (see Gevers and Lammertyn, 2005; Hubbard et al, 2005 for overviews). The spatial distances between the numbers clearly affected the comparison of numerical distances: Reaction times were faster and error rates smaller for congruent than for incongruent trials

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Conclusion