Mental state inferences - judgments about what others think, want, and feel - are central to social life. Models of such "mind-reading" have considered main effects, including social projection and stereotyping, but have not specified the conditions that govern when these tools will be used. This paper develops such a model, claiming that when perceivers assume an initial general sense of similarity to a target, they engage in greater projection and less stereotyping. Three studies featuring manipulations of similarity supported this claim. Moreover, reaction time results shed light on the mechanisms underlying these effects. The proposed model gives a new view of the mind-reader's toolkit and, more generally, raises questions about moderators of stereotyping and projection in social judgment.