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  • Writer's pictureCris

The halo effect

Let's judge these two people, Alan and Ben, according to the following personalities:

Alan: intelligent - industrious - impulsive - critical - stubborn - envious

Ben: envious - stubborn - critical - impulsive - industrious - intelligent

What do you think of them?

If you're like the majority of us, you thought Alan was much more positive than Ben. But why is that? When you've started reading, the first two or three adjectives gave you the first -- and very -- important impression about the two personalities.

Reading about Alan, you deliberately looked for adjectives confirming your first impression (positive test strategy). In fact, after having read Intelligent, you probably overlooked the adjectives industrious and stubborn. Likewise, reading about Ben, after reading Envious at the very beginning, you probably ignored the adjective intelligent at the end.

This example -- among many others explaining human biases -- is presented in "Thinking, Fast and Slow" by Daniel Kahneman (winner of the Nobel Prize) and this phenomenon is known by the name "The halo effect".

In the book, Daniel Kahneman shows how this effect kicks in every day. He noticed that "The halo effect" even influenced his exam grading. For instance, if he had to grade an exam with multiple questions, assuming every question had the same importance, he was more willing to give a higher grade to an exam with the first responses correct than to an exam with the last responses correct; even though the number of correct responses was the same!

The exams:

Exam 1: Yes - Yes - No - Yes - No - No

Exam 2: No - No - Yes - No - Yes - Yes

Were not evaluated the same!!!

In the same vein, if in a conference the first couple of talks are good, you will think also the others will be. Or, if you meet a good-looking person, you might think he or she also has other qualities.

As I already mentioned, our brains thrive on positive testing, but why is that? Our mind is a couch potato, less it can do, less it does; and since confirming an initial impression is "computationally" much less expensive than contradicting the same initial impression, our mind tends to find confirmation examples rather than examples that contradict our initial hypothesis. Because of this tendency, when grading Exam 1, we are more likely to prefer "ignoring" the third No and focus on the Yes instead, and while grading Exam 2, we do the vice-versa, as we did in the Alan and Ben example.

Have you ever heard about it? How often have you been a victim of this effect?


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