Decomposed but Parallel Processing of Two-Digit Numbers in 1st Graders

Abstract

It has been suggested that decomposed processing of two-digit numbersdevelops from sequential (left-to-right)to parallel with age (Nuerk et al., 2004). However, task demands mayhave provoked sequential processing as a specificrather than a universal processing style. In the current study a standardunit-decade compatibility effect observed intwo-digit number magnitude comparison indicated that first graderswere already able to process the single digitmagnitudes of tens and units separately and in parallel. Consequently,previous findings of sequential processing may bespecific for stimulus characteristics in which such a processing styleis useful. It is concluded that even first graders seemto be able to adapt their individual processing styles depending onstimulus properties. More generally, this suggeststhat the manner by which children process two-digit numbers is strategicallyadaptive rather than fixed at a particulardevelopmental stage.