The Importance of Magnitude Information in Numerical Processing: Evidence from the SNARC Effect

Models of the numerical cognitive system differ in the importance they attach to magnitude information in numerical processing. In this paper, the necessity of addressing a central semantic magnitude system in arabic number processing is evaluated by looking at the SNARC-effect (Dehaene, Bossini, & Giraux, 1993). The existence of a Spatial Numerical Association of Response Codes (small numbers are reacted to faster with the left hand, large numbers with the right hand) has been interpreted as an indication of access to the semantic system. In Experiment 1, we replicated the effect in a parity judgement task. In Experiment 2, we extended the SNARC-effect to a phoneme monitoring task, showing that magnitude information was accessed during arabic-to-verbal transcoding. Experiment 3 demonstrated that the SNARC effect in the phoneme monitoring task did not change with practice. We conclude, therefore, that number magnitude plays a more important role than is generally accepted.