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The Math That Explains How Misinformation Takes Hold
We’re currently neck-deep in reports of electoral calculations, but here’s another bit of math with jarring real-world implications: In the math publication Cantor’s Paradise, Jørgen Veisdal unpacks something called Concordet’s jury theorem, a probability thought exercise all about the wisdom of crowds — or lack thereof.
The theorem, by 18th-century French philosopher and mathematician Marie Jean Antoine Nicolas de Caritat, Marquis of Condorcet, holds that the more people you get to answer a given question, the greater the odds that most answers will be correct if three things are true: 1) the answer possibilities are binary, like yes or no; 2) each person individually is more than 50% likely to answer correctly; and 3) each person answers the question based on what they already know, not on new information.
On the flip side, if each person is less than 50% likely to get it right, then the more people you ask, the likelier it will be that group overall moves toward the wrong answer. Veisdal offers up this metaphor:
A group of people trying to…
