Abstract The “third-person effect” (also called “third-person perception” because it represents a difference between two perceptions) describes the inclination to overestimate the effects that mass communications (e.g., advertisements) have on others as compared to the self. We introduce the reflection hypothesis that predicts a notable exception from the general results pattern found in this research field. According to this hypothesis, asking for the effects of messages for desirable causes will result in a first-person effect (FPE), that is, a stronger perceived impact on the self than on others, under a specific condition: If effects on reflection (rather than effects on behavior) is used as the measure of perceived effectiveness. Results of two studies using mock non-profit advertisements as desirable messages confirmed this hypothesis. Because the reporting of an effect of a desirable message on the self can still be seen as supposed evidence of conformity, emergence of a FPE seems to depend on people being able to report an accepted version of conformity: the desirable message has an impact on their reflection (i.e., their thinking).