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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.

There is a lineup of nine bananas and one apple in an otherwise empty room. You know there are ten fruits in the room but need to know how many bananas there are. You are not allowed to look. But you are allowed to send in trusted friends to check for you. They enter the room on different days and are prevented from talking to each other. One hundred friends report back to you, one by one, and unanimously tell you there are nine bananas and one apple. What is the likelihood that there are really nine bananas in the room?

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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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