Two experiments, one conducted with American college students and one with Israeli pilots and their instructors, explored the predictive power of reputation-based assessments versus the stated "name of the game" (Wall Street Game vs. Community Game) in determining players' responses in an N-move Prisoner's Dilemma. The results of these studies showed that the relevant labeling manipulations exerted far greater impact on the players' choice to cooperate versus defect-both in the first round and overall-than anticipated by the individuals who had predicted their behavior. Reputation-based prediction, by contrast, failed to discriminate cooperators from defectors. A supplementary questionnaire study showed the generality of the relevant shortcoming in naive psychology. The implications of these findings, and the potential contribution of the present methodology to the classic pedagogical strategy ofthe demonstration experiment, are discussed.