Perceptual representations of romantic versus mother-child relationships: A combined behavioral, computational, and...

Romantic and mother-child relationships are fundamental to human social‑affective functioning. Previous research has consistently shown processing advantages for stimuli associated with both romantic partners and mothers. However, the common and distinct neural and cognitive mechanisms underlying these two central close relationships remain poorly understood. To address this question, the present study combined an associative matching task with electroencephalography (EEG) and computational diffusion modeling to compare perceptual‑decision processes and neural responses to partner‑ versus mother‑associated cues, and to examine their links with self‑reported relationship quality in young adults in romantic relationships (n = 40). During this task, participants were instructed to learn the matching rules between labels (r-partner, mother, self and stranger) and shapes (circle, square, triangle and diamond) and then judged whether the presented shape-label pairings were matched. Both behavioral and EZ‑diffusion modeling analyses showed comparable performance advantages for r-partner and mother stimuli relative to stranger stimuli. Similarly, event‑related potential (ERP) analyses revealed no significant differences between r-partner and mother conditions across early (P100, N200) and middle‑latency (P300) components. Crucially, however, a partner‑specific enhancement was observed in the late positive potential (LPP) relative to stranger, and the magnitude of this LPP bias was positively correlated with self-reported closeness to the r-partner. These results suggest that while romantic and mother‑child relationships engage shared perceptual‑decision mechanisms, romantic intimacy is uniquely associated with a late‑stage evaluative neural signature indexed by the LPP. The findings advance a dual‑process neurocognitive account of close relationships, distinguishing generalized affiliative processing from relationship‑specific motivational evaluation.