Recent social psychology is skeptical about self-knowledge. Philosophers, on the other hand, have produced a new account of the source of the authority of self-ascriptions. On this account, it is not descriptive accuracy but authorship which funds the authority of one's self-ascriptions. The resulting view seems to ensure that self-ascriptions are authoritative, despite evidence of one's fallibility. However, a new wave of psychological studies presents a powerful challenge to the authorship account. This research suggests that one can author one's attitudes, but one's self- ascriptions may lack authority. I present this new challenge from social psychology and use it to argue that first-person authority is agential authority: one's self-ascriptions are authoritative, in part anyway, because they are reliable expressions of those attitudes that govern further choices and behavior.