Three experiments examined whether perceiving thoughts as coming from internal versus external origins are more impactful on attitudes. Participants generated either positive or negative thoughts about different attitude objects, including different diets, and plastic surgery. Then, participants were induced to think that their thoughts came from the self or from an external source. In Experiment 1, participants induced to believe their thoughts originated from the self versus an external source relied on them more to form their attitudes. Experiment 2 demonstrated that when the external origin was associated with properties of validity, people relied on their thoughts more than when thoughts were perceived to come from an internal origin associated with low validity. Experiment 3 showed that the impact of thought origin on evaluations was mediated by greater liking for one's thoughts when they originated in the self.
Keywords: attitudes; origin; self-persuasion; source; validation.