The association between Machiavellian personality and relational deviance among corporate employees

Building on Dark Triad personality theory and moral self-regulation theory, and incorporating psychological capital (PsyCap) as a positive psychological resource, this study develops an integrated dispositional–moral regulatory–resource framework to examine the direct relationship between Machiavellian personality and relational deviance and the conditional moderating roles of moral disengagement and PsyCap. A cross-sectional design was employed, with data collected from 576 employees across various enterprises and institutions in Shandong Province, China, using an online survey. Valid responses were analyzed using SPSS 27.0. Measures included the Machiavellian Personality Scale, Relational Deviance Scale, Moral Disengagement Scale, and Psychological Capital Scale. Machiavellian personality was positively associated with relational deviance, and this relationship was stronger at higher levels of moral disengagement. PsyCap further conditioned this moderating pattern. When moral disengagement was low, high PsyCap was associated with an attenuated and nonsignificant relationship between Machiavellian personality and relational deviance. In contrast, when moral disengagement was high, the relationship was strongest at high levels of PsyCap. The findings reveal a potential “dark side” of PsyCap: the combination of high PsyCap and high moral disengagement strengthens the positive association between Machiavellian personality and relational deviance. This finding suggests that PsyCap may not function as an unconditionally protective resource; rather, its behavioral implications may be bounded by moral cognitive conditions, thereby extending our understanding of the boundary conditions of PsyCap’s behavioral effects.