Bishop, E G, & DiLalla, L.F. (1995). A study of mother-infant interaction: Similarities and differences in a sample of identical and fraternal twins. Paper presented to the Behavioral Genetics Association, June, Richmond, VA. Abstracted in Behavior Genetics, 21, 255.

One purpose of this research was to conduct behavior genetic analyses of quantified mother-child interaction behaviors in order to investigate the relative importance of genetic and environmental influences on these behaviors. Subjects in this study were participants at 7 and 9 months of age in the Twin Infant Project (TIP; L.F. DiLalla et al., 1990, Developmental Psychology, 29, 434- 447), some of whom also participated at 14 and 24 months of age in the MacArthur Longitudinal Twin Study (MLTS; R. Plomin et al., 1993, Child Development, 64, 1354-1376). The child behaviors coded at 7 and 9 months of age were Affection for Mother, Responsiveness to Mother, Negativity, and Task Orientation. Preliminary results (N= 32 families at 7 and 9 months only) are as follows: At 7 months, MZ twins’ behaviors were significantly correlated on Affection for Mother (r= .68, p<.001) and Responsiveness to Mother (r= .41, p<.05), while DZ twins’ behaviors were not significantly correlated on any measure. At 9 months, MZ twins’ behaviors were significantly correlated on Affection for Mother (r= .40, p<.05), Responsiveness to Mother (r= .38, p<.05), and Task Orientation (r= .54, p< .001), and again, DZ twins’ behaviors were not significantly correlated on any measure. Further analyses will be conducted with a larger sample size, including the other two age points (14 and 24 months), in order to explore the possible genetic/environmental influences working on the particular mother-child interactive behaviors under consideration.