Maternal affective environment and the twin relationship

Date of Completion

January 2002


Psychology, Behavioral|Psychology, Social




This study utilized a behavior genetic twin design to investigate questions surrounding differences in the maternal affective environment within the twin-pair. Affective environment was measured by maternal attachment inventories and a measure of Positive Interactions derived from s novel inventory. Data was collected from 181 mothers of twins, ages 10 to 18-month-olds. Of these 181 twins pairs, 69 were monozygotic and 112 were dizygotic. Of these 112 pairs, 73 were same-sex dizygotic ^ It was hypothesized that variances in twin-twin attachment differences could be predicted based upon variables in the maternal environment. A novel inventory, the Mother-Twin-Twin Unique Relationship Inventory, was created to assess the influence of infant health, maternal stress, and maternal sense of self variables on differences in attachment scores. It was expected that mothers who experienced the greatest amount of environmental stress, whose infant twins had the poorest health history, and who had the weakest sense of self profiles would have the largest difference in twin-twin attachment scores. ^ The findings indicated that while immediate environmental variables do not have a significant impact on interpair difference, a mother's attachment history and sense of self were predictive of interpair attachment difference. These findings are consistent with the concept of the intergenerational transmission of attachment. ^