Grammatical number as linguistic quantity: spatial-response compatibility effects in Turkish

A growing body of research suggests that numerical magnitude is associated with spatial response coding, as demonstrated by the Spatial-Numerical Association of Response Codes (SNARC) effect. Recent work has extended this question beyond Arabic digits to linguistic expressions of quantity, including grammatical number. The present study examined whether Turkish singular and plural word forms show spatial-response patterns compatible with SNARC-like mappings. Eighty-six native speakers of Turkish completed a combined Go/No-Go lexical decision and grammatical number judgment task. Participants responded to real Turkish words while withholding responses to pseudowords; response mappings were counterbalanced such that singular forms were associated with the left-hand response and plural forms with the right-hand response in the typical mapping condition, with the reverse assignment in the non-typical mapping condition. Reaction times were analyzed using linear mixed-effects models. Participants responded faster in the typical mapping condition than in the non-typical mapping condition, and plural forms elicited slower responses than singular forms overall. However, the interaction between grammatical number and response mapping was not significant. These findings suggest that Turkish grammatical number can interact with spatial response organization, but the observed pattern is better interpreted as a general SNARC-compatible mapping advantage rather than a fully differentiated spatial mapping of singular and plural forms. The form of this association may depend on task characteristics.