When we meet someone for the first time and see neat clothes and a bright smile, we somehow get the feeling that they must be good at their job and have a good personality too. Cosmetics advertised by a favorite actor can seem high-quality even before we have tried them. This phenomenon, in which one noticeable strength brightly lights up other aspects of a person or thing, is the ‘Halo Effect.’
Put simply, the halo effect means ‘a bias in judgment in which the impression formed from one prominent trait drags along our evaluation of other, unrelated traits.’ The name comes from the ring of light painted behind the heads of saints in medieval and Renaissance paintings, the halo. Just as a single light makes a whole face look bright, one strength colors the overall evaluation brightly.
In this piece, we will look in turn at the research that first identified the halo effect, the principle by which judgment gets bent, examples in everyday life and the market, and finally ways to reduce the bias.
How One Strength Colors the Whole
How Was the Halo Effect Discovered?
This phenomenon was first pointed out in 1907, but the person who confirmed it with actual data and gave it a name was Edward Lee Thorndike, a pioneer of the psychology of learning.
(1) Military Commanders’ Rating Sheets
In his 1920 paper “A Constant Error in Psychological Ratings,” Thorndike analyzed data from military commanders’ ratings of the soldiers under them. The commanders scored each item separately: physical qualities such as physique, voice, and neatness; intelligence; leadership; and character traits such as loyalty and responsibility.
(2) Correlations Too High and Too Even
The analysis showed that scores on items that should have had little to do with each other moved together far too much. The correlation between physique and intelligence averaged 0.31, and the correlation between physique and leadership reached 0.39. Thorndike explained that raters first feel about a person as a whole, as ‘pretty good’ or ‘not so good,’ and then let that feeling color the scores for individual qualities.
The Psychology That Bends Judgment
The halo effect is not an illusion that occurs only when information is lacking. Even traits that could easily be judged separately get pulled along by the overall impression, and the person judging does not notice it.
(1) The Warm Instructor and the Cold Instructor
In 1977, Richard Nisbett and Timothy Wilson filmed two versions of an interview with a college instructor who spoke English with a European accent. In one video the instructor was warm and friendly, and in the other cold and distant. After 118 college students watched a video, they rated the instructor’s appearance, mannerisms, and accent; the students who saw the warm instructor called them appealing, while those who saw the cold instructor said they were irritating. And this was the same person with the same appearance and accent.
(2) An Influence We Don’t Notice in Ourselves
Even more surprising were the students’ explanations. The students who saw the cold instructor said it was not that they disliked the instructor and therefore rated the appearance low, but that the appearance and accent were irritating and so they came to dislike the instructor. In effect, they had the direction of the actual influence backward.
(3) Central Traits That Bind First Impressions
In 1946, Solomon Asch showed that changing just one word in a list of personality traits, ‘warm’ or ‘cold,’ greatly changes the overall impression of a person. As such central traits become the standard for interpreting the rest of the information, the halo spreads widely.
The Halo Effect in Everyday Life and the Market
The halo effect seeps into our judgments everywhere, outside the laboratory as well.
- Appearance (Attractiveness Halo): In a 1972 experiment by Karen Dion and her colleagues, college students predicted that the people in photos of attractive faces would also have better personalities and be more successful in marriage and at work. This result is known as the stereotype that ‘what is beautiful is good.’
- The Workplace (Performance Appraisal): When a boss gets a good impression from an employee’s enthusiasm alone, they tend to give a high overall rating even if the employee lacks job knowledge or ability. It is considered one of the most common errors in performance reviews.
- Brands (Brand Halo): Just as interest flowed to Apple’s other products after the iPod became a big success, a good experience with one product spreads to the same company’s other products. This is also why the high-performance cars that automakers produce in small numbers are called ‘Halo Cars.’
- Health Halo: A single phrase such as ‘organic’ or ‘low-fat’ can make an entire product look healthy, and can even lead people to eat more of it.
The Opposite Horn Effect and How to Reduce Bias
The halo effect also works in reverse. The phenomenon in which one noticeable flaw drags down the whole evaluation is called the Horn Effect. The name comes from the devil’s horns, in contrast to a saint’s halo, and a person who made a bad first impression is easily doubted even for the things they did well.
(1) Breaking Items Apart and Rating Them Separately
In interviews and grading, setting evaluation items in advance and rating everyone on one item at a time can reduce the way one person’s overall impression spreads across many items.
(2) Hiding Irrelevant Information
Methods that keep evaluators from seeing information unrelated to the evaluation from the start, such as blind hiring or grading with names on answer sheets covered, are also effective.
(3) Writing Down the Reasons for a Judgment
Writing down ‘why I gave this score’ in terms of specific behaviors or results lets you check for yourself whether a vague liking moved the score.
The halo effect is a side effect of the mental shortcuts we use to judge a complex world quickly. Guessing about a person or thing from a first impression and a single strength happens to everyone, and people who evaluate others for a living, like Thorndike’s commanders, are no exception. What matters is not eliminating this bias entirely, but the habit of asking once more, at the moment of judgment, where that light is coming from.
Calmly looking at the other sides hidden behind a shining strength: that is the first step in psychology toward seeing people and the world fairly.
