B. W. A. Whittlesea and L. D. Williams (1998, 2000) proposed the discrepancy-attribution hypothesis to explain the source of feelings of familiarity. By that hypothesis, people chronically evaluate the coherence of their processing. When the quality of processing is perceived as being discrepant from that which could be expected, people engage in an attributional process; the feeling of familiarity occurs when perceived discrepancy is attributed to prior experience. In the present article, the authors provide convergent evidence for that hypothesis and show that it can also explain feelings of familiarity for nonlinguistic stimuli. They demonstrate that the perception of discrepancy is not automatic but instead depends critically on the attitude that people adopt toward their processing, given the task and context. The connection between the discrepancy-attribution hypothesis and the "revelation effect" is also explored (e.g., D. L. Westerman & R. L. Greene, 1996).