Cloninger’s model originally consisted of three dimensions of personality (temperaments): Novelty Seeking, Harm Avoidance, and Reward Dependence, measured by the Tridimensional Personality Questionnaire (TPQ; Cloninger, 1986; Cloninger, Przybeck, & Svrakic, 1991). Reward Dependence originally included items measuring persistence, but the persistence items were later revealed to be uncorrelated with other Reward Dependence items; in a revised model, Persistence was designated as a fourth dimension of temperament (Cloninger, 1994). Although Cloninger also extended his model with three additional character (aspects of self concept) dimensions, measured by the Temperament and Character Inventory (TCI), we focus here on the four dimensions of temperament. Correlations between the different temperament scales are low and principal components analysis identifies each temperament as a separate factor (Cloninger, Svrakic, & Przybeck, 1993; Keller, Coventry, Heath, & Martin, 2005).
