The halo effect

What it says

The halo effect is the pull of one general impression on judgments that should be separate. Somebody who seems warm in the first minutes of an interview starts to look better organized and more able as well. Nothing about their organization has been seen. The warmth is doing the rating.

It runs in both directions. A bad first impression drags down ratings of work it has nothing to do with. People often call that the horns effect, a popular name rather than a research term. The mechanism is the same either way: a general feeling stands in for a specific judgment.

What makes it hard to catch is that it does not feel like anything. Asked afterward, people explain each rating on its own terms and deny that the overall impression had a hand in it. Some report the reverse, that the details shaped the overall view.

Four places it shows up

The same pull, in the settings where the research has measured it.

1. Ratings of people at work

   Thorndike found that officers who rated the men under them gave scores that agreed with each other far too neatly. A man rated high on one quality was rated high on nearly all of them.

2. Appearance

   Dion, Berscheid and Walster showed raters photographs and nothing else. The people judged attractive were also judged kinder, more successful and more likely to be happy.

3. Work on the page

   Landy and Sigall found the same essay was graded higher when the reader believed the writer was attractive, and the gap was widest for the weak essay.

4. The reverse direction

   One irritating trait drags down ratings of work it has nothing to do with. The popular name is the horns effect, but it is the same pull running the other way.

Where it came from

Edward Thorndike named it in a 1920 paper called A constant error in psychological ratings. He had the ratings that army officers gave their men on intelligence, physique, leadership and character. The qualities agreed far more than they could in real people. A constant error was his phrase: a bias running the same way through every rating, not noise.

The best known demonstration is Richard Nisbett and Timothy Wilson's, from 1977. Students watched a taped interview with a college instructor who spoke with a Belgian accent. Half saw him answer warmly, half saw him answer coldly. Then both halves rated things the tapes shared: his looks, his mannerisms, his accent. The warm group liked them, and the cold group found the same features irritating. Asked whether their overall impression had colored those ratings, most said it had not.

What holds up, and what does not

The effect is one of the most repeated findings in the study of judgment. It shows up in the classroom, in hiring, in performance reviews and in product ratings, and it is strongest when the rater has little to go on. It is not quite the whole story. Kevin Murphy and colleagues argued in 1993 that some of the agreement between ratings is real. People who are good at one thing are often good at related things, and a rating form cannot tell the real overlap from the borrowed kind.

What blunts it is procedure, not effort. Rate each quality before forming an overall view. Ask every candidate the same questions in the same order and score each answer against a standard. Hide what the rater does not need, such as the name and the photograph on a work sample. Structured interviews sit among the better predictors of later performance in Frank Schmidt and John Hunter's 1998 review. Part of the reason is that structure leaves a halo less room.

What it does not mean

It does not mean first impressions are wrong, or that a warm person is secretly disorganized. Warmth and competence are separate questions, and the halo effect is the habit of answering the second with the first. It is not a flaw of careless raters either. Nisbett and Wilson's students were moved and could not see it. That is why watching yourself is a weak defense and changing the order of the work is a better one.

Check yourself

Three questions on what is above. Each answer says why.

1. Pick the statement that describes the halo effect.

   1. One general impression of a person spreads into separate ratings of them
   2. A person judged well on one quality is usually good at the others
   3. Raters give higher scores to people they have met in person
   Show the answer

   Answer: A. The halo effect is a general impression standing in for specific judgments. Whether the qualities really go together is a separate question, which is what makes the halo hard to see.

2. In the 1977 taped instructor study, what did students say when asked whether their overall impression had colored their ratings of his accent and mannerisms?

   1. Most said it had not, and some said the details had shaped the overall view
   2. Most said it had, and described how
   3. They could not remember the instructor at all
   Show the answer

   Answer: A. The students denied the pull, and some reported it running the other way. That denial is the point: a halo moves ratings without the rater feeling moved.

3. Which change does the research support as a way of blunting the halo effect in hiring?

   1. Asking interviewers to be more careful
   2. Scoring each answer against a standard, in the same order for every candidate
   3. Forming an overall impression first and then filling in the details
   Show the answer

   Answer: B. Structure limits what a general impression can borrow. Trying harder does not, because the pull is not felt, and forming the overall view first is the order that lets the halo in.

Sources

1. Thorndike, E. L. (1920). A constant error in psychological ratings. Journal of Applied Psychology, 4(1).
2. Nisbett, R. E., and Wilson, T. D. (1977). The halo effect: Evidence for unconscious alteration of judgments. Journal of Personality and Social Psychology, 35(4).
3. Dion, K., Berscheid, E., and Walster, E. (1972). What is beautiful is good. Journal of Personality and Social Psychology, 24(3).
4. Landy, D., and Sigall, H. (1974). Beauty is talent: Task evaluation as a function of the performer's physical attractiveness. Journal of Personality and Social Psychology, 29(3).
5. Murphy, K. R., Jako, R. A., and Anhalt, R. L. (1993). Nature and consequences of halo error: A critical analysis. Journal of Applied Psychology, 78(2).
6. Schmidt, F. L., and Hunter, J. E. (1998). The validity and utility of selection methods in personnel psychology: Practical and theoretical implications of 85 years of research findings. Psychological Bulletin, 124(2).

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