Halo–horns effect
Also known as: Horn effect, Devil effect
The dark twin of the halo effect: one bad trait taints all judgments.
What it means
The negative counterpart to the halo effect, in which a single unfavorable trait or first impression leads observers to assume other, unrelated characteristics are also negative. Just as a positive quality can cast a flattering glow over the whole person, a salient flaw casts a shadow that biases perception of competence, honesty, and worth downward. The horns effect is amplified by negativity bias, which gives unfavorable information disproportionate weight, making negative halos quick to form and slow to revise. Together the halo and horns effects describe how global impressions distort specific judgments in either direction. They shape interviews, performance reviews, customer perceptions, and the durability of bad first impressions.
Examples
An applicant with an unprofessional email address is also presumed careless and unintelligent, regardless of an otherwise strong résumé.
One rude waiter at the door and the whole evening is remembered as poor — the food, the room, even the prices judged downward from a single sour first impression.
A pupil who arrives late in the first week is later read as lazy rather than unlucky, and years of teachers inherit the reputation without ever testing it themselves.
First described in Counterpart to Thorndike (1920); negativity bias literature.