Three studies tested the hypothesis that when people receive persuasive messages, their perceptions of the information on which they base their attitudes can determine feelings of subjective ambivalence. Across studies, it is shown that when elaboration (e.g., need for cognition, personal relevance) is high, people have more subjective ambivalence when they perceive that they have based their attitudes on the source of a message rather than the arguments contained in that message. When elaboration is low, this effect is reversed. These findings suggest that people can assess the informational basis of their attitudes and that these assessments influence feelings of attitude ambivalence.