Exploration into the sources of individual differences in Aggression-, Hostility- and Anger-related (AHA) personality traits

In this study a behavior-genetic approach was used to identify sources of individual differences in Aggression-, Hostility- and Anger-related (AHA) personality traits (as measured with Spielbergerʹs anger scales and scales from the Karolinska Scales of Personality), based on a sample (N = 140 individuals) that comprised of monozygotic twin pairs reared together (Npairs = 26) or reared apart (Npairs = 15), and dizygotic twin pairs reared together (Npairs = 29). In general, the results suggest that environmental factors account for sibling similarity in hostility, whereas genetic factors account for sibling similarity in angry aggression and irritability (trait anger).