Halo Effect

The halo effect is the habit of letting one standout quality color our judgment of everything else about a person. Its mirror image, often called the horn effect, lets one weakness darken the rest.

Where it comes from

In 1920, psychologist Edward Thorndike asked military officers to rate their soldiers on traits such as intelligence, physique and leadership. The ratings agreed with each other far more than the traits themselves should have, as if a general impression had spread across the whole list.¹ In 1977, Richard Nisbett and Timothy Wilson showed students a video of the same instructor acting either warm or cold. Students who saw the warm version rated his appearance, mannerisms and accent more favorably, and they were largely unaware of the influence.² Phil Rosenzweig later applied the idea to business writing: when a company thrives, observers praise its culture, leadership and strategy, and when results slip, the same traits are described as flaws.³

Where it goes wrong

Confident presenters are often assumed to be strong managers, and a strong first quarter can make a whole career look brilliant. The effect also works in reverse, so one early mistake can follow someone through every review that comes after it.

¹ Thorndike, E. L. (1920). A constant error in psychological ratings. Journal of Applied Psychology, 4(1), 25–29.

² Nisbett, R. E., & Wilson, T. D. (1977). The halo effect: Evidence for unconscious alteration of judgments. Journal of Personality and Social Psychology, 35(4), 250–256.

³ Rosenzweig, P. (2007). The halo effect: ... and the eight other business delusions that deceive managers. Free Press.

Further reading: Rosenzweig, P. (2007), as above, for the business applications.