The mental representation of parity and number magnitude.

TLDR

Nine timed odd‑even judgment experiments investigated how parity and magnitude are accessed from Arabic and verbal numerals. Arabic numerals trigger rightmost‑digit access to semantic number knowledge and automatic magnitude retrieval, while verbal numerals require transcoding to base‑10; large numbers elicit rightward responses, small numbers leftward, and the SNARC effect depends solely on relative magnitude, being weaker or absent with letters or verbal numerals and reversing in right‑to‑left writing cultures.

Abstract

Nine experiments of timed odd-even judgments examined how parity and number magnitude are accessed from Arabic and verbal numerals. With Arabic numerals, Ss used the rightmost digit to access a store of semantic number knowledge. Verbal numerals went through an additional stage of transcoding to base 10. Magnitude information was automatically accessed from Arabic numerals. Large numbers preferentially elicited a rightward response, and small numbers a leftward response. The Spatial-Numerical Association of Response Codes (SNARC) effect depended only on relative number magnitude and was weaker or absent with letters or verbal numerals. Direction did not vary with handedness or hemispheric dominance but was linked to the direction of writing, as it faded or even reversed in right-to-left writing Iranian Ss