Abstract
The literature on spatial associations during number processing is dominated by the SNARC (spatial–numerical association of response codes) effect. We describe spatial biases found for single digits and pairs of numbers, first in the “original” speeded parity task and then extending the scope to encompass different tasks, a range of measures, and various populations. Then we review theoretical accounts before surveying the emerging evidence for similar spatial associations during mental arithmetic. We conclude that the mental number line hypothesis and an embodied approach are useful frameworks for further studies.
We thank Matthias Hartmann and Oliver Lindemann for helpful discussions.This work was funded by DFG [grant number FI 1915/2-1 “Manumerical cognition” to M.H.F.].
Notes
1A number pair is compatible in this sense when separate unit and decade comparisons lead to the same outcome (as for the pair 42 and 57, where 4 < 5 and 2 < 7) but otherwise incompatible (as for the pair 47 and 62, where 4 < 6 but 7 > 2). Whether systematically faster decisions for compatible pairs are consistent with holistic number representations for double-digit numbers, or else imply separate number lines for units and decades, is discussed in the review by Nuerk, Moeller, Klein, Willmes, and Fischer (Citation2011).