Halo effect

“I use a first impression to draw a ‘bigger picture’ conclusion.”


The halo effect happens when a first impression based on a single trait is generalized towards other, sometimes unrelated aspects of the object being evaluated. This cognitive bias happens when people make quick judgments about a person, based on their favourable or negative impression of a characteristic. The halo effect is not limited to people, and can also happen when we judge things like companies or places. The feeling that is generated from the first impression is transferred onto other facets that have not actually been explored [1]. Although it is more commonly associated with a positive bias, it can also result in a negative bias depending on the nature of the initial impression [2]. The term halo effect comes from the fact that one trait overcasts a judgement, similarly to a halo that is sometimes depicted in religious paintings as overcasting a person [1].


A company is hiring for a position. The person in charge of hiring is faced with two candidates, both have average resumés with a similar experience in the field. Before conducting the interview, the person in charge of hiring sees the candidates sitting side by side and finds that one of them is more physically attractive than the other. Finding someone beautiful triggers a positive impression and an overall good feeling. This good feeling is then generalized to the candidate’s other characteristics, such as competency. The beautiful person is therefore perceived as smarter, more responsible and more qualified because of the halo effect. The employer is therefore more likely to hire the good-looking candidate.


The halo effect is a well-known psychological phenomenon. Despite this, we have many different hypotheses for its explanation, meaning that we still do not have one clear answer as to why it occurs [3]. One of the most common explanations for the halo effect involves cognitive mechanisms, such as the automatic and constructive Gestalt process. This is essentially the process of linking together the many pieces of information that we have available to have it form a coherent whole (like linking up pieces of a puzzle and seeing the final big picture) [3]. The halo effect, on the other hand, uses only one piece of information, and generalizes it to form a complete image. Despite this small distinction, it is thought that a mechanism such as the Gestalt process could be at the root of the halo effect.

Other theories include the “mood congruency effect”. Researchers in psychology have found that being in a good mood makes positive information more accessible in our minds. If a piece of information is easily accessible, it is more likely to be used when making a quick judgement. Hence, when in a good mood, the small bit of positive information that is already on hand is more likely to be used when forming a fast opinion about an object, thus inducing the halo effect. Mood also influences how the information is treated in our minds [3]. For example, if you are happy, you are more likely to view the things around you as positive, whereas if you are sad, you are more likely to view these same things from a pessimistic perspective. Therefore, being in a good mood could make you more likely to use a positive aspect of an object when making a fast judgement, and a bad mood could make you more likely use a negative aspect of an object when forming an opinion. Thus, mood can impact the tone of the judgement formed by the halo effect.


The halo effect can have repercussions in many different areas of our lives. As discussed in the example, it can play an important role during job interviews; in a situation where two candidates have equivalent backgrounds, the halo effect can cause the employer to choose the candidate that is the most physically attractive. More generally, the common conception that what’s beautiful is good is an example of the halo effect [4]. In politics, a politician who presents as warm and friendly is more likely to be appreciated and supported by people, even when they do not verbalize many ideas or concrete plans [2]. The marketing domain often takes advantage of the halo effect. For example, a nice packaging or advertisement can cause people to conclude that the product must be good. The halo effect can be present any time there is an interaction between people [2, 3].

Thoughts on how to act in light of this bias

  • Fun fact: simply being aware of this bias does not make you less likely to commit it. In one study, people were explicitly told about the halo effect before being asked to complete a task, and yet they still manifested the bias [4].

  • A more systematic, and more thorough thinking process is shown to reduce the halo effects [3].

  • Being in a negative mood reduces halo effects (not to say that you should be in a bad mood but try to be aware of the contagious effect an overly good mood can have on decision making) [3].

How is this bias measured?

This bias is typically measured by showing recordings of people to participants, and then asking them to (1) rate their first impressions and (2) infer other traits the subject might have that were not explored in the video. A classic study involved showing college students video tapes of a professor. Half the participants saw a video tape in which the professor has a warm and positive attitude. The other half of participants saw a video in which the same professor has a cold and neutral attitude. After having watched the tapes, the students were asked to rate the teacher’s likeability, physical attractiveness, and how much they liked his accent. It was found that students who saw the first tape found the professor more attractive, and his accent more likeable. The students with the second tape found the teacher’s physical appearance and accent to be irritating. This demonstrates that in both cases, the initial judgement that was made by the students (based on the teacher’s “warmth”) impacted their opinion on other unrelated traits (such as the teacher’s physical attractiveness, likeability, and accent), which demonstrates that the halo effect was at work in these cases [2].

This bias is discussed in the scientific literature:


This bias has social or individual repercussions:


This bias is empirically demonstrated:



[1] Nisbett, Richard E. & Timothy D. Wilson (1977). The halo effect: evidence for unconscious alteration of judgments. Journal of Personality and Social Psychology 35(4): 250.

[2] Abikoff, Howard, Mary Courtney, William E. Pelham & Harold S. Koplewicz (1993). Teachers' ratings of disruptive behaviors: The influence of halo effects. Journal of Abnormal Child Psychology 21(5): 519-533.

[3] Forgas, Joseph P. (2011). She just doesn't look like a philosopher…? Affective influences on the halo effect in impression formation. European Journal of Social Psychology 41(7): 812-817.

[4] Wetzel, Christopher G., Timothy D. Wilson & James Kort (1981). The halo effect revisited: Forewarned is not forearmed. Journal of Experimental Social Psychology 17(4): 427-439.


Individual level, Interpersonal level, Intergroup level, Representativeness heuristic, Need for cognitive closure

Related biases

  • Horn effect

  • Substitution bias

  • Mood congruence effect

  • Synonym: halo error


Camille Comeau is currently working towards a bachelor’s in psychology at the Université de Montréal.

How to cite this entry

Comeau, C. (2021). Halo effect. In C. Gratton, E. Gagnon-St-Pierre & E. Muszynski (Eds). Shortcuts: A handy guide to cognitive biases Vol. 4. Online: www.shortcogs.com.

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