Predicting Power and Gender Harassment from HEXACO and Dark Traits

Abstract Workplace harassment imposes substantial individual and organizational costs, yet the relative contributions of antagonistic “dark” traits and broader personality dimensions remain debated. This study examined how the HEXACO model—focusing on Honesty–Humility—adds to the prediction of harassment tendencies beyond the Dark Triad (Machiavellianism, narcissism, psychopathy) in Japanese adults. Participants completed the HEXACO-60, the SD3-J, and validated measures of power harassment and gender harassment. We reported Spearman correlations and multiple regressions with HC3 robust standard errors, and we evaluated incremental validity by adding HEXACO traits to Dark Triad–only models. Across models, psychopathy emerged as a consistent positive predictor of power harassment (β≈.32–.40, p<.001), whereas Honesty–Humility showed a protective association (β≈−.14, ~p=.05), with Agreeableness additionally protective in sensitivity analyses (β≈−.17, p<.01). For gender harassment, narcissism and psychopathy were positive predictors, while Honesty–Humility and Openness were negative predictors; notably, Machiavellianism displayed negative coefficients in adjusted models. Adding HEXACO traits increased explained variance beyond the Dark Triad (ΔR²≈.032, p=.036 for power harassment; ΔR²≈.096, p<.001 for gender harassment), indicating meaningful incremental validity—especially for gender harassment. Model diagnostics supported the use of robust inferences (non-normality/heteroskedasticity present; low multicollinearity; results stable after excluding high-influence cases). Findings underscore psychopathy as a central risk factor and Honesty–Humility as a cross-situational protective factor, suggesting that personnel risk assessment and harassment prevention in Japanese workplaces can benefit from integrating HEXACO—particularly Honesty–Humility—alongside dark-trait screening.