Semantic Modulation of Spatial Judgments in Augmented Reality: Evidence from fNIRS

This study examined how different types of semantic relationships modulate cortical activity during spatial judgments in an augmented reality (AR) setting. Participants viewed triads of everyday objects that were either thematically (co-occurring) or functionally (sharing a purpose) related and made spatial judgments varying in reference frame, egocentric (object closest to you?) vs. allocentric (object closest to another? ), and relation type, coordinate (distance-based) vs.categorical (left-right). Cortical activity was measured using functional near-infrared spectroscopy (fNIRS). Results showed that semantic modulation was most evident during allocentric-coordinate judgments, with increased activation in temporal regions for thematic triads compared to functional ones. In general, functionally related triads engaged parietal regions more broadly across conditions, while egocentric judgments elicited widespread parietal activity with reduced semantic modulation. Finally, categorical judgments showed minimal differences between semantic conditions. By combining AR with fNIRS, this study provides evidence that semantic knowledge influences cortical recruitment during spatial processing, offering a novel window into how meaning and spatial representation interact.