Resemblances of twins and their parents in pattern A behavior.

A twin study was conducted to determine the relative contribution of genetic and environmental factors to the development of Pattern A behavior. Thirty-five sets of college-aged MZ twins and 21 sets of DZ twins completed the lenkins Activity Survey for Health Prediction. This self-administering questionnaire yields scales measuring Pattern A behavior and its related traits of Speed and Impatience, Job Involvement, and Hard-driving Competitiveness. Results showed a modest genetic component for the Hard-driving Competitive aspect of Pattern A. Data were also presented regarding resemblances between the twins and their parents on Pattern A.