Variations in the oxytocin receptor gene and prosocial behavior: moderating effects of situational factors

Humans are the most prosocial primate species and they often exhibit high levels of prosocial behavior toward genetically unrelated individuals. Traditional evolutionary theories are not sufficient to explain the individual differences and mechanisms related to prosociality. In this study, we focused on the gene-situation interaction in prosocial behaviors, and the patterns of genotype variance related to cooperation and comforting in different situations. We explored the interaction between the oxytocin receptor (OXTR) gene and situations, and the genotype variance under low and high prosociality situations between outgroup and ingroup recipients in a sample of 422 Chinese males. Prosociality was tested by measuring the prosocial tendencies, and prosocial behaviors were tested in cooperation and comforting tasks. OXTR single nucleotide polymorphisms (SNPs) were genotyped using polymerase chain reaction-restriction fragment length polymorphism analysis. The results suggested that the relationship between OXTR SNPs (specifically rs13316193, rs1042778 and rs237887) and prosocial behavior varied across different situations, and that the associations were moderated by the recipient's identity and the prosocial cost. Our findings indicate the action of a moderating mechanism between the OXTR gene and prosocial behaviors according to situational factors.