What Is the Halo Effect?

Medically Reviewed by Smitha Bhandari, MD on June 22, 2024
4 min read

The halo effect is a cognitive bias. 

What is a cognitive bias? It’s a preconceived opinion you form about other people and things. It is not based on an objective analysis, and you form it for no real reason except what you happen to notice. 

You might unknowingly experience the halo effect every day.

The halo effect influences how you think about others. It happens when you automatically make positive assumptions or judgments about people based on something positive you notice. In reality, you know little about them, but you subconsciously attach a “halo” to them anyway because you think they seem nice.

The halo effect is a form of stereotyping. You assume everyone who exhibits a particular trait is the same and make assumptions about them that might be untrue. 

As part of the halo effect, you notice a single trait about someone and then attach other qualities to them and form an overall impression. When you notice a positive trait and then make positive assumptions, it’s called the halo effect. When you notice a negative trait and form a negative impression, it’s called the horn effect. 

A common halo effect example is attractiveness, and the tendency to assign positive qualities to an attractive person. For example, you might see a physically beautiful person and assume they are generous, smart, or trustworthy. This bias is so common that the halo effect is sometimes generalized to refer to the specific assumption that “what is beautiful is good”. 

One study showed that people make these assumptions about youthfulness, too. People are more likely to have more favorable perceptions of people with a younger, baby-like appearance than those who appear older

Psychologist Edward Thorndike first described the halo effect in 1920. In a study called “A Constant Error in Psychological Ratings,” he asked military officers to rank soldiers. He thought that in a fair approach, they would consider each trait by itself, but that’s not what happened.

Thorndike found that the officers gave soldiers higher rankings based on first impressions of their appearance. If the officers noticed a trait, they would jump to conclusions, and the final assessment would match the initial impression. 

Presumptions can be helpful. They allow you to notice your surroundings and quickly judge whether you’re safe. They also help you socially and allow you to fill in unspoken information about others that guide your response. For example, you might notice someone crying, assume they’re sad, and seek to offer comfort. 

However, biases like the halo effect can influence everything in your awareness, right down to the food you buy, and distort the truth unhelpfully. Marketing plays on your perceptions. Images and information on labels can influence your view of a product, making something seem healthy even if is not.

It’s hard to escape biases, though, and it takes conscious effort and self-awareness to get beyond them. It’s possible that you might view other people or things through the halo effect, and other people most likely do the same to you. You experience such biases in almost every part of your daily life. 

The halo effect is often at play in your workplace. You might learn your coworker went to a prestigious university and assume they’re more qualified, even if they aren’t. If your colleague dresses sharply, you might assume they’re a hard worker, but that might not be true.

Unfortunately, the halo effect can also interfere with your earnings. Thorndike’s original study with the officers and soldiers is a good example of workplace bias, but modern research also shows these effects. 

In one study, attractive female restaurant servers earned about $1200 more a year in tips than their so-called unattractive coworkers. The study found that female customers tipped beautiful female servers more than they tipped male servers or unattractive female servers. 

Research on packaging information shows that you’re likely to think a food is healthier than it is based on the nutrition claims. When a package labels a granola bar as a “ protein bar”, for example, you’re more likely to assume the bar is healthy, even if the label clearly shows it has lots of sugar and calories.

Another example is the term “organic.” In one study, researchers used the same foods but gave some people an organic label and others a regular label. Those with the organic label had an overall higher perception of the food. They liked it more, were willing to pay more for it, and assumed it was healthier and had lower calories than it did. They also had more positive emotions toward the food. 

You often use the halo effect to judge the quality of your medical treatment, too. One study showed that patients who had a good “hotel” experience at a hospital gave the hospital a higher overall rating. 

The rating had nothing to do with medical treatment, patient safety, healthcare quality, or even a lower risk of dying. If the room was quiet and the nurses talked to them, patients had a higher impression of the treatment they had received. 

Unfortunately, the halo effect can also influence how others view your health. If you are nicely groomed or attractive, someone might assume you’re healthy or you have good mental health. In reality, these things can be unrelated, and you can’t always tell when someone is unwell.

You’ve probably fallen for the halo effect at some point. Unfortunately, it leads to an error in judgment and can affect your relationships and your daily life. 

Fortunately, being aware of this effect can help you make better decisions.