Despite the wide use of the Tridimensional Personality Questionnaire (TPQ) in Western populations as a useful tool integrating both genetic and environmental influences on personality, some of its constructs remain questionable. In this study, we examined the psychometric properties of the TPQ and its relationship with aggression in Taiwanese adults. The subjects were 201 Taiwanese adults of wide ranges in age and educational level. Subjects were assessed using a Chinese version of the TPQ and the Brown-Goodwin Aggression Inventory. The internal consistency of the Chinese version of the TPQ scales is found to be mostly in the acceptable range except for the reward dependence (RD) scale and its subscales. The results of factor analysis of the 12 TPQ subscales partially support the four-factor model rather than the original three-factor model. The construct validity of the novelty seeking (NS) and harm avoidance (HA) dimensions is supported by the findings that the NS is negatively correlated with age, the NS1 subscale is slightly negatively correlated with all the HA subscales, and the NS is positively correlated with aggression. We conclude that both the HA and NS scales of the TPQ are cross-culturally robust, while the RD scale needs to be refined. Copyright 2002, Elsevier Science (USA). All rights reserved.A LARGE NUMBER of studies have consistently revealed that there are three to five discrete quantifiable and heritable traits that comprise human personality and predispose individuals to behave in certain consistent ways. [1][2][3][4][5][6] Recently, there has been increased interest in applying molecular genetic techniques to decipher the genes responsible for the variations in personality trait. 7 In this regard, the biosocial theory of personality put forth by Cloninger 1,8 is heuristically useful because it attempts to integrate information from family studies, longitudinal development research, psychometric descriptions of personality structure, and neuropharmacological and neuroanatomical studies of conditioning and learning in man and animals.Cloninger 1,8 proposed that there were three genetically independent dimensions of personality: novelty seeking (NS), harm avoidance (HA), and reward dependence (RD). NS is characterized by an inherited tendency toward the activation of behavior such as exploratory activity in response to novelty, impulsive decision making, extravagance in the approach to cues of reward, and quick loss of temper. HA is defined as an inherited tendency toward the inhibition or cessation of behaviors, such as pessimistic worry in anticipation of future problems, passive avoidant behaviors such as fear of uncertainty and shyness of strangers, and rapid fatigability. RD is assumed to be an inherited tendency toward the maintenance of ongoing behaviors, and is exhibited as sentimentality, persistence, social attachment, and dependence on the approval of others. Individual differences along these three dimensions reflect variations in the monoaminergic brain systems of behavioral activ...