Halo Effect
Also known as: Halo Error
Formulated by Edward Thorndike (1920)
Definition
A cognitive bias in which the overall impression formed of a person, brand, or product from a single trait, whether positive or negative, spills over and distorts judgment of that same person, brand, or product on other, entirely unrelated traits. First documented by psychologist Edward Thorndike in his 1920 study of military officers, who found that raters who judged a soldier physically impressive also tended to rate him higher on wholly unrelated qualities like intelligence, leadership, and character, purely on the strength of that first impression. The bias runs both ways: a single negative trait can just as easily taint every other judgment, an asymmetric mirror image sometimes called the horn effect. It is exploited constantly outside the lab: attractive people are assumed more competent and trustworthy, a charismatic CEO's one hit product lends unearned credibility to a company's entire lineup, and a well-liked public figure gets the benefit of the doubt on claims that would otherwise draw scrutiny.