Professor

The horn effect refers to the unjustified transfer of a negative impression from one observed attribute or event to judgments about other, insufficiently evidenced attributes. This professional review situates the concept within research on halo effects, negative information, and person perception, and examines its relevance to employment, education, politics, public communication, and organizational reputation. It distinguishes an inference error from a warranted adverse assessment: an established failure can be consequential without providing evidence of unrelated failures. Experimental work documents the influence of global impressions on separate trait ratings, while research on performance appraisal and crisis response shows why domain relevance, attribution, and prior information matter. The review proposes criteria for recognizing the effect, methodological approaches for studying it, and practical safeguards that separate observations, interpretations, and decisions. Its central argument is that accurate judgment requires evidence specific to the attribute under consideration; correcting a bias does not require dismissing genuine harm or suspending accountability.