Roles of culture and COMT Val58Met gene on neural basis of executive function: A comparison between Japanese and American children.

The development of executive functions (EF) is shaped by both genetic and environmental factors, including cultural background. Genetically, variation in the catechol-O-methyltransferase (COMT) gene polymorphism has been linked to EF performance and differential regulation of prefrontal cortex activity. Based on the gene-culture interaction framework, we tested whether culture would moderate the association between the COMT gene and young children's behavioral responses and neural activities during a cognitive-shifting EF task. The children who participated in this study were 5- to 6-year-olds in Japan (n = 44) and in the U.S. (n = 47). The results revealed that U.S.-American children exhibited stronger activations than Japanese children in the right dorsolateral and bilateral prefrontal cortex regions. In addition, the children's genetic disposition and EF performance were marginally moderated by culture, with Val homozygote Japanese children performing better than Met-allele carriers, whereas no such differences were found in U.S.-American children. We have discussed the theoretical and empirical implications of the construction of a more complete understanding of EF development by incorporating both genetic and socio-cultural factors.