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Should you trust unanimous decisions? - Derek Abbott

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TEDEd Animation

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Imagine a police lineup where ten witnesses are asked to identify a bank robber they glimpsed fleeing the scene. If six of them pick the same person, there’s a good chance that’s the culprit. And if all ten do, you might think the case is rock solid. But sometimes, the closer you start to get to total agreement, the less reliable the result becomes. Derek Abbott explains the paradox of unanimity.

This time there’s a lineup of nine red apples and a rubber ball about the same size and color as the apples in the room. You are not told how many apples there are and you send your friends to find out for you. This time each person is only allowed to look at the lineup for 10 seconds through the keyhole of the locked room. One hundred friends independently agree on the same number of apples. What is the likelihood you have been given the correct number?

About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here »

Meet The Creators

  • Educator Derek Abbott
  • Script Editor Alex Gendler
  • Director Brett Underhill
  • Animator Brett Underhill
  • Narrator Addison Anderson

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