The dark side of the rainbow: Homosexuals and bisexuals have higher Dark Triad traits than heterosexuals

Research on the Dark Triad traits—psychopathy, Machiavellianism, and narcissism—reveals malevolent, transgressive, and self-centered aspects of personality. Little is known about the Dark Triad traits in individuals differing in sexual orientation, with some studies showing that non-heterosexual individuals have Dark Triad profiles resembling those of opposite-sex heterosexual individuals. In a cross-national sample (N = 4063; 1507 men, 2556 women; Mage = 24.78, SDage = 7.55; 90.58% heterosexual, 5.74% bisexual, 2.83% homosexual) collected online via student and snowball sampling, we found in sex-aggregated analyses that bisexuals and homosexuals were more Machiavellian than heterosexuals. Bisexuals were more psychopathic and narcissistic than heterosexuals. The only significant findings in within-sex comparisons showed that self-identified bisexual women scored higher on all Dark Triad traits than heterosexual women. The findings support the gender shift hypothesis of same-sex sexual attraction in bisexual women, but not in lesbians nor in men. The finding that bisexuals are the sexual orientation group with the most pronounced Dark Triad profiles is opposite to what would be predicted by the prosociality hypothesis of same-sex sexual attraction. The life history and minority stress implications of these findings are discussed as alternative hypotheses to the gender shift hypothesis.