According to the literature, personality traits are considered efficient predictors of levels and forms of civic engagement and political participation. As concerns offline forms of political participation, personality traits have been shown to be mediated by interest in politics, political efficacy and interpersonal discussion about politics. However, the effects of personality traits on online forms of political engagement have been largely understudied. The present cross-sectional research (N = 601, young adult sample) had three main goals. The first one was to replicate previous results concerning the link between personality traits, as measured by the Big Five Inventory, on legal and illegal offline political activities. The second goal was to explore the dimensionality of online political participation. The third goal was to explore the relationships between personality traits and online political participation. Structural equation model results supported previous findings indicating that the positive effects of Openness to experience and Extraversion on the engagement in legal political activities were, at least partially, mediated by political efficacy, interest in politics, and interpersonal discussions; Agreeableness had a negative direct effect on the engagement in illegal political activities, while Openness to experience had a positive indirect effect on it. Exploratory factorial analysis indicated that online political participation had three dimensions related to information seeking, supportive participation, and content generation. Structural equation model showed that Openness to experience had positive indirect effects on the three forms of online participation, while Conscientiousness and Agreeableness had negative effects on information seeking and supportive participation. The impact of Conscientiousness was totally mediated by the time spent on Internet. The results showed that personality traits play an important, even if mostly indirect, role in predicting offline and online political activities. It is concluded that not only offline but also online political activities seem to be marked by a personality divide.
