Interpersonal Neural Synchronization during Interpersonal Touch Underlies Affiliative Pair Bonding between Romantic Couples

TLDR

Interpersonal touch is essential for forming and maintaining romantic pair bonds, yet the underlying neurocognitive mechanisms remain poorly understood. The study tests whether interpersonal neural synchronization during touch underlies affiliative bonding between romantic couples. Using fNIRS hyperscanning, the authors compared INS between heterosexual couples and opposite‑sex friends while they engaged in touch or vocal communication. Couples showed significantly higher INS in mentalizing and sensorimotor networks during touch than during speech, and this touch‑induced INS correlated with self‑reported love strength, with men’s empathy further amplifying the relationship—supporting a role for INS and empathy in romantic bonding.

Abstract

Abstract Interpersonal touch plays a key role in creating and maintaining affiliative pair bonds in romantic love. However, the neurocognitive mechanism of interpersonal touch in affiliative pair bonding remains unclear. Here, we hypothesized that interpersonal neural synchronization (INS) during interpersonal touch underlies affiliative pair bonding between romantic couples. To test this hypothesis, INS between heterosexual romantic couples and between opposite-sex friends was measured using functional near-infrared spectroscopy-based hyperscanning, while the pairs of participants touched or vocally communicated with each other. The results showed significantly greater INS between the mentalizing and sensorimotor neural systems of two members of a pair during interpersonal touch than during vocal communication between romantic couples but not between friends. Moreover, touch-induced INS was significantly correlated with the self-reported strength of romantic love. Finally, the results also showed that men’s empathy positively modulated the association between touch-induced INS increase and the strength of romantic love. These findings support the idea that INS during interpersonal touch underlies affiliative pair bonding between romantic couples and suggest that empathy plays a modulatory role in the neurocognitive mechanism of interpersonal touch in affiliative pair bonding.