The halo effect is a type of cognitive bias in which our overall impression of a person influences how we feel and think about his or her character. Essentially, your overall impression of a person ("He is nice!") impacts your evaluations of that person's specific traits ("He is also smart!"). One great example of the halo effect in action is our overall impression of celebrities. Since we perceive them as attractive, successful, and often likable, we also tend to see them as intelligent, kind, and funny.

 
Definitions of the Halo Effect

Also known as the physical attractiveness stereotype and the "what is beautiful is good" principle, the halo effect, at the most specific level, refers to the habitual tendency of people to rate attractive individuals more favorably for their personality traits or characteristics than those who are less attractive. Halo effect is also used in a more general sense to describe the global impact of likable personality, or some specific desirable trait, in creating biased judgments of the target person on any dimension. Thus, feelings generally overcome cognitions when we appraise others.
Psychologist Edward Thorndike first coined the term in a 1920 paper titled "The Constant Error in Psychological Ratings." In the experiment described in the paper, Thorndike asked commanding officers in the military to evaluate a variety of qualities in their subordinate soldiers. These characteristics included such things as leadership, physical appearance, intelligence, loyalty, and dependability. He found that high ratings of a particular quality correlated to high ratings of other characteristics, while negative ratings of a specific quality also led to lower ratings of other characteristics.
 

Consequences of the Halo Effect

Several different studies have found that when we rate people as good-looking, we also tend to believe that they have positive personality traits and that they are more intelligent. One study even found that jurors were less likely to believe that attractive people were guilty of criminal behavior.However, this attractiveness stereotype can also be a double-edged sword. Other studies have found that while people are more likely to ascribe a host of positive qualities to attractive people, they are also more likely to believe that good-looking individuals are vain, dishonest, and likely to use their attractiveness to manipulate others.

 
In school. The halo effect can influence how teachers treat students, but it can also impact how students perceive teachers. In one study, researchers found that when an instructor was viewed as warm and friendly, students also rated him as more attractive, appealing, and likable. In the classroom, teachers are subject to the halo effect rating error when evaluating their students. For example, a teacher who sees a well-behaved student might tend to assume this student is also bright, diligent, and engaged before that teacher has objectively evaluated the student's capacity in these areas. When these types of halo effects occur, they can affect students approval ratings in certain areas of functioning and can even affect students' grades.

 
Marketers take advantage of the halo effect to sell products and services. When a celebrity spokesperson endorses a particular item, our positive evaluations of that individual can spread to our perceptions of the product itself.

Job applicants are also likely to feel the impact of the halo effect. If a prospective employer views the applicant as attractive or likable, they are more likely to also rate the individual as intelligent, competent, and qualified.

 
Politics. Deciding which political candidate to vote for, consider how overall impressions of an individual might influence evaluations of other characteristics. Does impression of a candidate being a good public speaker lead you to feel that she is also smart, kind, and hard-working?

 
Being aware of the halo effect, however, does not make it easy to avoid its influence on our perceptions and decisions.