title: To carry or not to carry--is this the question? Disentangling the carry effect in multi-digit addition.
abstract: Recent research has suggested addition performance to be determined by both the need for a carry operation and problem size. Nevertheless, it has remained debatable, how these two factors are interrelated. In the current study, this question was pursued by orthogonally manipulating carry and problem size in two-digit addition verification. As the two factors interacted reliably, our results indicate that the carry effect is moderated by number magnitude processing rather than representing a purely procedural, asemantic sequence of processing steps. Moreover, it was found that the carry effect may not be a purely categorical effect but may be driven by continuous characteristics of the sum of the unit digits as well. Since the correct result of a carry problem can only be derived by integrating and updating the magnitudes of tens and units within the place-value structure of the Arabic number system, the present study provides evidence for the idea that decomposed processing of tens and units also transfers to mental arithmetic.
authors.affiliation: Section Neuropsychology, Department of Neurology, University Hospital, RWTH Aachen University, Germany. elise.klein@uni-tuebingen.de
authors.forename: Elise
authors.initials: E
authors.lastname: Klein
authors.forename: Korbinian
authors.initials: K
authors.lastname: Moeller
authors.forename: Katharina
authors.initials: K
authors.lastname: Dressel
authors.forename: Frank
authors.initials: F
authors.lastname: Domahs
authors.forename: Guilherme
authors.initials: G
authors.lastname: Wood
authors.forename: Klaus
authors.initials: K
authors.lastname: Willmes
authors.forename: Hans-Christoph
authors.initials: HC
authors.lastname: Nuerk
mesh_terms: D000328:Adult; D001288:Attention; D005260:Female; D006801:Humans; D008297:Male; D008433:Mathematics; D008570:Memory, Short-Term; D011340:Problem Solving; D011930:Reaction Time