Thomas Costello

The present investigation examined curvilinear relations between political ideology, on the one hand, and absolute certainty and dogmatism, on the other, across six online samples ( N = 2,889). Ideological extremists were more likely than others to be absolutely certain: About one in three extremists reported being absolutely (i.e., 100%) certain of the correctness of their political beliefs, whereas about one in 15 non-extremists reported being absolutely certain. Although absolute political certainty was relatively symmetrical across the political left and right, conservatives tended to report greater domain-general dogmatism than liberals. Extremism effects for domain-general dogmatism were also present, however; and ideological asymmetries in dogmatism appeared to be driven by social, rather than economic, ideology. Taken together, these findings underscore the complexity of relations between absolute certainty, dogmatism, and ideology, ultimately challenging the sufficiency of contemporary psychological accounts of ideological (a)symmetries to describe our complex political reality.