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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.

Consider a bank robber fleeing from a bank and jumping into a car. Twenty witnesses on the sidewalk get a fleeting glimpse of the man for about 10 seconds each. Three days later, during a police lineup all 20 witnesses agree the same suspect is the bank robber. What is the likelihood they have correctly identified the criminal?

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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