Dissociation between spontaneous gaze shifts and the spatial coding of number magnitude: Evidence from four high-resolution eye-tracking experiments

Does the brain representation of number magnitude inherently involve space? Early studies suggested that merely perceiving or judging numbers automatically shifts attention and gaze leftward for small numbers and rightward for large ones, supporting the existence of an inherent space-number association. More recent evidence, however, has challenged this view, indicating that spatial-numerical effects arise primarily when spatial and magnitude codes are jointly engaged for response selection. Across four high-resolution eye-tracking experiments, we tested whether discriminating the magnitude of spoken number words elicits overt oculomotor gaze shifts. In Experiments 1-3, participants made verbal magnitude judgments to auditorily presented number words (1-9, excluding 5) while viewing a blank screen (Experiment 1), a Hermann grid designed to facilitate eye movements (Experiment 2), or horizontally symmetrical landscapes presented with or without lateral distractors (Experiment 3). Across all conditions, we found no evidence of horizontal or vertical gaze shifts associated with number magnitude. In Experiment 4, participants explicitly mapped magnitude judgments onto spatial response codes, producing a space-number association of response codes effect. Nevertheless, no spontaneous magnitude-congruent gaze shifts emerged. These findings indicate that number magnitude does not inherently trigger spatially directed eye movements and that spatial-numerical associations depend on task-driven recruitment of both magnitude and spatial response codes. (PsycInfo Database Record (c) 2026 APA, all rights reserved).