ABSTRACT Taylor and Brown (1988) hypothesized that certain illusions, such as unrealistic optimism, are predictably associated with positive affect, social skills, and intellectual functioning. To test this hypothesis, we obtained data from 162 students who first filled out a questionnaire containing dispositional measures of affect, social skills, and approaches to problem solving; in a second session they completed three tasks requiring difficult decisions, reporting their confidence in each decision. Accuracy of judgments was found to vary considerably from task to task, but confidence ratings showed a consistent pattern of individual differences. This result lent support to Taylor and Brown's hypothesis, as did other features of the data, most notably several small but significant Pearson rs between confidence ratings and dispositional variables. Removing the effects of accuracy from these rs reduced their magnitude very little; it yielded partial rs interpretable as evidence that illusory confidence is associated with personality traits which, in this case, load saliently on factors labeled (a) affective, and (b) cognitive/social.