This talk features neuroscientist Mariano Sigman, recorded at TED studio in 2017.

As societies, we have to make collective decisions that will shape our future.

And we all know that when we make decisions in groups, they don't always go right.

And sometimes they go very wrong.

So how do groups make good decisions? Research has shown

that crowds are wise when there's independent thinking. This is why the wisdom of the crowds can

be destroyed by peer pressure, publicity, social media, or sometimes even simple conversations

that influence how people think. On the other hand, by talking, a group could exchange knowledge,

correct and revise each other, and even come up with new ideas.

And this is all good.

So does talking to each other help or hinder collective decision-making?

With my colleague Dan Ariely, we recently began inquiring into this by performing experiments

in many places around the world to figure out how groups can interact to reach better

decisions.

We thought crowds would be wiser if they debated in small groups that foster a more thoughtful

and reasonable exchange of information.

To test this idea, we recently performed an experiment in Buenos Aires, Argentina, with more than 10,000 participants in a TEDx event.

We asked them questions like, what is the height of the Eiffel Tower,

and how many times as the word yesterday appear in the Beatlesiddle song yesterday. Each person wrote down their

own estimate. Then we divided the crowd into groups of five and invited them to come up with a group

answer. We discovered that averaging the answers of the groups after they reached consensus

was much more accurate than averaging all the individual opinions before debating.

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