A study in female prairie voles found that a natural genetic variation in the oxytocin receptor gene makes some females more likely to watch unfamiliar males from a distance during early social interactions. The version of the gene linked to higher receptor levels in a brain region called the nucleus accumbens caused this increased social observation. This suggests that tiny genetic differences can subtly shape how social cues are noticed before bonds form.

Genetic variation in the oxytocin receptor gene ( <i>Oxtr</i> ) has been linked to differences in brain OXTR expression and long-term social bonds, but whether it shapes the moment-to-moment dynamics of early social interactions is unclear. Here we examined how the intronic <i>Oxtr</i> single nucleotide polymorphism (SNP) NT213739 in female prairie voles ( <i>Microtus ochrogaster</i> ) shapes their dynamic social interactions with an opposite-sex conspecific. Leveraging a computational pipeline to analyze the movements of freely interacting voles, we found that C/C females, which expressed higher OXTR levels in the nucleus accumbens than T/T females, spent more time socially observing novel males from a distance, especially early in interactions. This genotype-phenotype relationship persisted in multiple contexts, including the social preference test. Thus, natural <i>Oxtr</i> variation biases social observation in females toward unfamiliar males before bonds form, consistent with models where accumbens OXTR enhances the salience of social cues. These findings show that SNPs can shape subtle behavioral dimensions in early social encounters, with important implications for the role of oxytocin in the study of social attachment.