The halo effect refers to the tendency to allow one specific trait or our overall impression of a person, company or product to positively influence our judgment of their other related traits. A single positive quality of a person may induce a positive predisposition toward every aspect of that person while one negative attribute of that person may induce an overall negative impression of that person. It is called the Horn effect.
For example, suppose you perceive a person to be warm and friendly. In that case, you will attribute a number of other associated traits to that person without any knowledge that they are true, such as they are generous. The Halo and Horn Effects are an example of a cognitive bias we are all subject to. They are forms of stereotyping. Imagine someone really attractive walks into the room. You might be thinking: “They must be smart, funny, and just like me!” Let’s say someone isn’t attractive, has a bad sense of fashion. We might then assume they are incompetent at work or socially inept. We think of them without knowing the important information to make those judgments. When we are stuck in the Horn Effect, we also may minimize positive things about that person. Teachers might believe that students who are well-mannered are smarter, better than those who are not, or assume that previous good grades mean that they have the same knowledge on different subjects and the opposite.
The word ‘halo’ stems from a religious concept. It refers to a circle of light that is placed above or around the head of a holy person or saint in order to honor his or her sanctity. Countless paintings from the Middle Ages and the Renaissance period depict notable men and women with the heavenly light of the halo.