title: On the development of the mental number line: more, less, or never holistic with increasing age?
abstract: Magnitude is assumed to be represented along a holistic mental number line in adults. However, the authors recently observed a unit-decade compatibility effect for 2-digit numbers that is inconsistent with this "holisticness" assumption (H.-C. Nuerk, U. Weger, & K. Willmes, 2001). This study used the compatibility effect to examine whether the mental number line representation of magnitude changes toward greater or less holisticness in children from Grades 2-5. The results indicate that decades and units of 2-digit numbers are processed separately rather than holistically from Grade 2 on. However, this separate processing seems to develop from a more sequential (left-to-right) to a more parallel processing mode. Moreover, children may use different strategies depending on task demands. The results are interpreted in the framework of Siegler's overlapping waves model.
authors.affiliation: Neuropsychology Section, Department of Neurology, University Hospital of the Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, Aachen, Germany. nuerk@neuropsych.rwth-aachen.de
authors.forename: Hans-Christoph
authors.initials: HC
authors.lastname: Nuerk
authors.forename: Liane
authors.initials: L
authors.lastname: Kaufmann
authors.forename: Sabine
authors.initials: S
authors.lastname: Zoppoth
authors.forename: Klaus
authors.initials: K
authors.lastname: Willmes
mesh_terms: D002648:Child; D002657:Child Development; D003071:Cognition; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008433:Mathematics