Abstract
<title>Abstract</title> <p>The spatial-numerical association of response codes (SNARC) effect refers to faster left-hand responses to small numbers and faster right-hand responses to large numbers. A growing body of evidence indicates that the SNARC effect is not a fixed expression of spatial-numerical representation but is modulated by cognitive control. The numerical distance effect reflects the principle that magnitude comparisons are facilitated by greater numerical disparity and impeded by proximity. From a cognitive-control perspective, the present study examined whether numerical distance modulates the SNARC effect and whether this modulation is reflected in conflict-monitoring processes indexed by event-related potentials (ERPs). The study comprised two behavioral sub-experiments and one ERP experiment. Experiments 1a and 1b used Chinese Mahjong bamboo- and circle-suit numerals, respectively, to examine the interaction between numerical distance and SNARC compatibility, whereas Experiment 2 used Arabic numerals combined with ERPs to examine the neural mechanisms of this interaction. Across all experiments, robust distance effects were observed. Importantly, the SNARC effect was significant in the far-distance condition but was absent in the close-distance condition. In Experiment 2, this interaction was reflected in frontal N2 latency: SNARC-incompatible trials elicited longer N2 latencies than compatible trials in the far-distance condition, but not in the close-distance condition. These findings indicate that numerical distance dynamically modulates the SNARC effect and suggest that this modulation emerges at the conflict-monitoring stage.</p>