Genetic variability in the oxytocin system is linked to individual differences in cuddliness among human infants.

ABSTRACT

Pleasant touch facilitates social interactions, affiliative behavior and emotional bonding, contributing to positive infant and child development. Oxytocin is presumed to play an important role in mediating these effects of pleasant touch on brain, body and behavior. However, little is known about the role the oxytocin system plays in pleasant touch during infancy. This study examined the hypothesis that genetic variability in the oxytocin system is linked to individual differences in infants' cuddliness operationalized as parent-reported behaviors indexing an infant's motivation to seek out and enjoy caregiver touch. Our results (N = 82) show that a polymorphism in CD38 (rs3796863), previously linked with increased release of oxytocin in adults, was associated with higher reported rates of cuddliness. In contrast, infants with CD38 genotype previously linked to autism spectrum disorder (ASD) and reduced release of oxytocin in adults, was associated with lower rates of cuddliness. These findings support the hypothesis that, from early in human ontogeny, genetic variation in the oxytocin system is systematically linked to individual differences in the reported motivation to seek out, and the enjoyment of receiving, pleasant caregiver touch. This provides novel insights into the neurohormonal processes involved in pleasant touch.