Numerical Acuity as an Attentive Process: Evidence from Electrophysiological Data

This research investigates whether numerosity abilities — specifically non-symbolic numerical acuity — are truly preattentive or whether they rely on visuo-spatial attention resources. While much of the existing literature suggests that numerical acuity operates independently of attentional mechanisms, recent evidence proposes an alternative view: that early visuo-spatial attention plays a role in numerical discrimination. To test this, we used a dot comparison paradigm in which the numerical discrepancy between two hemifields was manipulated to create easier and harder trials. Participants were asked to judge which side contained more or fewer dots. We then conducted an event-related potential (ERP) analysis focusing on the N2pc component — a well-established marker of lateralized attentional allocation — to determine whether attention is engaged during numerical comparison and how this engagement varies with task difficulty. EEG data were preprocessed and analyzed using EEGLAB (MATLAB), and statistical analysis was performed in RStudio. This study aims to clarify the role of visuo-spatial attention in non-symbolic numerical tasks and contribute to the broader understanding of attentional mechanisms in numerosity perception.