Dilalla, L.F., Jones, S.D., Bishop, E G, & Bhutwala, S. (1998). Differential maternal treatment of twins: Does temperament make a difference? Poster presented to the International Conference on Infant Studies, April, Atlanta. Abstracted in Infant Behavior and Development, 21, 382.

Research has shown that parents treat children in the same family similarly in terms of warmth but not in terms of control. This suggests that parental warmth is a pervasive trait whereas parental control is more environmentally mediated. A comparison of differential treatment toward identical (MZ) and fraternal (DZ) twins provides a perspective on how variably parents treat children of the same ages, and helps to untangle confounds in previous research looking at children of different ages.

Twins were videotaped interacting with their mothers during a vocal elicitation (7 and 9 months) and teaching (14, 24, and 36 months) task longitudinally. Mothers were rated on behaviors that assessed warmth and control; children were coded for watching mom and working on task. Child temperament was rated using the Infant Behavior Checklist (IBR) and included measures for Task Orientation and Affect/Extraversion.

Differential treatment was unrelated to temperament ratings suggesting that there is no systematic relationship between infant temperament and maternal warmth and controlling behaviors, at least in these small samples of behavior. However, mothers tended to treat their two children more similarly on the dimension of maternal warmth than on control. Maternal controlling behaviors differed as a function of children’s behaviors during the interactions, especially for fraternal twins who already differed on a number of different traits. This study of twin siblings addresses the current issue of why children raised in one family may differ so dramatically from each other.