The development of empathy in twins.

This study examined empathy in 94 monozygotic (MZ) and 90 dizygotic (DZ) twin pairs during the 2nd year of life. Children's reactions to simulations of distress in others were videotaped in home and laboratory settings. Some components of concern for others increased with age between 14 and 20 months for both MZ and DZ twins. Girls scored higher than boys on most of these observational measures. The different components (e.g., emotional concern, prosocial acts, and cognitive exploration) showed substantial coherence and low but significant stability over time. There was modest evidence for heritability of empathy, particularly for the affective component. Maternal reports of prosocial orientations indicated both genetic and environmental influences