Groups of people make more effective decisions when diverse viewpoints are brought to the table. Learn the psychology of non-conformity and how it applies to your team in this lesson excerpt from economist Tim Harford. The full lesson is available on Big Think+.

Tim Harford: We often hear people singing the praises of diversity, and there are lots of good reasons why we should have diversity – to correct historic injustices and to be fair to all sorts of different kinds of people. Less often we hear the benefit of diversity because it just helps groups of people make better decisions. It’s not just some concession we make to political correctness. It makes our decisions more effective.

So a fantastic example of this goes way back to the 1950s, research conducted by a psychologist called Solomon Asch. And what Solomon Asch did was he lined a bunch of people up and showed them two flashcards. One had three lines on – slightly different lengths – and the second card had a single line on – this is the reference line. He showed them these two lines and he said, “Which of these three lines is the same length as the reference line, A, B or C?” And then he’d go down the line of people and he’d ask them.

So say the answer’s B. You go down the line and the first person says, “A.”  And the second person says, “A.” The third person says, “A.” The fourth person says, “A.”  The fifth person says, “A.” Now there’s this person at the end of the line who’s now feeling really weird because he can see that the answer’s B. And yet everyone in the room is saying A. And he’s sweating, he’s checking his watch, he’s giggling. These people started showing signs of real pressure. Very often, though, they would say, “A,” even though the answer was pretty clearly B.

And, of course, you can guess what’s going on. Solomon Asch is playing a trick on people. All of these people in the line, they’re all actors that were working for Solomon Asch except the one person towards the end of the line who’s being experimented on. So that’s an indicator of the power of conformity to get us to just shut up about what we think is true and not reveal our ideas. And it happens in much more naturalistic settings as well.