In dialogue with recent developments in the literature on political behavior, the article analyzes the effects of ideological extremism and political dogmatism on the levels of activism of the São Paulo electorate. Considering the recent context of political polarization observed in Brazil, the main objective is to assess the extent to which this phenomenon contributes to accentuating the asymmetries that are already quite expressive in participatory behavior. Electoral, non-electoral and contestatory forms of political action are considered, and the main proposed predictors are extremism in ideological self-positioning, closure to dialogue, and rigidity of opinion, the latter two being taken as measures of dogmatism. Using data from the "Local Democracy Index" Project, we tested the hypotheses that extremism and dogmatism would be positively related to greater political activism and that the combination of these characteristics intensifies this relationship. The results partially confirm these hypotheses, indicating the existence of cleavage between extremists and moderates, especially regarding the left, which is more likely to engage in various forms of political involvement. As for dogmatism, contrary to our hypothesis, there were negative effects.