Sibling interactions, self-regulation, and cynical hostility in adult male twins.

Chronic hostility is associated with increased vulnerability to serious physical illness, making developmental influences on this trait important. We used the Structural Analysis of Social Behavior (SASB) model to examine retrospective descriptions of twin interactions during childhood in a sample of 48 adult male twin pairs. Consistent with previous research on parental behavior correlates, self-reported hostility as measured by the Cook and Medley Ho scale was associated with descriptions of the twin's behavior as hostile, controlling, and neglecting. Consistent with the SASB principle of introjection, hostility was also associated with self directed hostility and neglect. Thus, a developmental perspective not only describes possible social contexts involved in the emergence of this trait, but also suggests possible psychological underpinnings. Implications for models of hostility and health are discussed.