This research was aimed to provide a comprehensive test of the classic notion that narcissistic individuals are appealing as short-term romantic or sexual partners. In three studies, we tested the hypotheses that narcissism exerts a positive effect on an individual's mate appeal and that this effect is mediated by high physical attractiveness and high social boldness. We implemented a multimethod approach and used ratings of opposite sex persons (Study 1), ratings of friends (Study 2), and records of courtship outcomes in naturalistic interactions (Study 3) as indicators of mate appeal. In all cases, narcissism had a positive effect on mate appeal, which was mainly due to the agentic self-enhancement aspects of narcissism (rather than narcissists' lacking communion). As predicted, physical attractiveness and social boldness mediated the positive effect of narcissism on mate appeal. Findings further indicated that narcissism was more strongly linked to mate appeal than to friend appeal.

The metric level of invariance offers the possibility of comparing correlates and predictors of positive mental functioning across countries; however, the comparison of the levels of mental health across countries is not possible due to lack of scalar invariance. Our study has preliminary character and could serve as an initial assessment of the structure of the MHC-SF across different cultural settings. Further studies on general populations are required for extending our findings.

The current study provides the first examination of the relationship between life history indicators and the Dark Triad traits in an international sample drawn from the U.S. (n = 264), Singapore (n = 185), and Poland (n = 177). In all three samples, the Dark Triad traits were associated with psychosocial costs, although there were more links in the Singaporean and Polish samples than in the American sample. In the U.S., the quality of one's romantic relationships and psychopathy were negatively correlated. Narcissism was higher in the Polish and American samples than in the Singaporean sample. Men scored higher than women did regardless of location and the sex difference in the individual differences in life histories was mediated by the Dark Triad composite. Results suggest the Dark Triad are related to a volatile socioecology composed of psychosocial costs in the familial, romantic, and platonic relationships.

In five studies (total N = 1300) we developed and validated a Polish version of the Dirty Dozen measure (DTDD-P) that measures the three traits of the Dark Triad, Machiavellianism, psychopathy, and narcissism. We detail the presence and stability of a bifactor structure of the 12 items and present evidence for good internal consistency and test–retest reliability. We examine the nomological network surrounding the Dark Triad and show that both the Dark Triad total score and the subscales have acceptable validity. We also present evidence on the Dark Triad and moral behavior. Dark Triad predicts utilitarian moral choice (e.g., approval for sacrificing somebody's life for the sake of saving others) and this link is mediated by low empathic concern. In total, our results suggest that the Polish Dirty Dozen—Parszywa Dwunastka—is valid, stable, and useful for the study of lingering puzzles in the literature.