Genetic Variability in OXTR Polymorphism and Infant Reactivity to Ostracism Experiences

The oxytocin system is central to regulating social behaviors, with genetic variations in the oxytocin receptor gene (OXTR), particularly the rs53576 single nucleotide polymorphism (SNP), linked to individual differences in emotional reactivity and social cognition. GG genotype carriers typically show heightened sensitivity to social dynamics, exhibiting greater empathy and prosocial behaviors in positive contexts but also increased anxiety and emotional dysregulation in response to negative social stressors, such as ostracism. Although these associations are well established in adults, little is known about the impact of genetic variability in the oxytocin system on infants' behavioral and emotional reactivity to ostracism experiences. The current study investigated whether rs53576 allelic variations influence 13-month-olds' (N = 56, 41% males; mostly White) affective and behavioral reactions to ostracism episodes during a live-triadic ball-tossing game. Results demonstrated that GG carriers show heightened sensitivity to ostracism compared to AA/AG carriers. Specifically, ostracized GG infants exhibited a more pronounced decrease in Positive Emotionality and an increase in Negative Emotionality. Current findings underscore the role of genetic predispositions in enhancing sensitivity to social experiences, shaping infants' early interactions within their social environment.