found that people are more likely to attribute intentionality to agents whose actions resulted in negative side-effects that to agents whose actions resulted in positive ones. Subsequent investigation has extended this result to a variety of other folk psychological attributions. The present article reports experimental findings that demonstrate an analogous effect for belief ascriptions. Participants were found to be more likely to ascribe belief, higher degrees of belief, higher degrees of rational belief, and dispositional belief to agents in central Knobe effect cases who bring about negative side-effects than to agents who bring about positive ones. These findings present a significant challenge to widely held views about the Knobe effect, since many explanations of it assume that agents in contrasting pairs of Knobe effect cases do not differ with respect to their beliefs. Participants were also found to be more confident that knowledge should be attributed than they were that belief or dispositional belief should be attributed. This finding strengthens the challenge that Myers-Schulz and Schwitzgebel (forthcoming) have launched against the traditional view that knowledge entails belief. keywords: Knobe effect, experimental philosophy, belief ascription, folk psychology * Thanks to