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The Real Wisdom of the Crowds – Phenomena

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The story of how a school of fish is smarter than individual fish:

In 1907, Sir Francis Galton asked 787 villagers to guess the weight of an ox. None of them got the right answer, but when Galton averaged their guesses, he arrived at a near perfect estimate. This is a classic demonstration of the “wisdom of the crowds”, where groups of people pool their abilities to show collective intelligence. Galton’s story has been told and re-told, with endless variations on the theme. If you don’t have an ox handy, you can try it yourself with beans in a jar.

To Iain Couzin from Princeton University, these stories are a little boring. Everyone is trying to solve a problem, and they do it more accurately together than alone. Whoop-de-doo. By contrast, Couzin has found an example of a more exciting type of collective intelligence—where a group solves a problem that none of its members are even aware of. Simply by moving together, the group gains new abilities that its members lack as individuals.

Couzin–one of National Geographic’s Emerging Explorers–has spent his whole career studying animals that move in shoals, flocks and swarms. His early work involved ants and locusts but when he started his own lab at Princeton, he thought he’d upgrade to a smarter group-living species. Unfortunately, he ended up with the golden shiner—a small, bland, minnow-like fish that’s dumb beyond the telling of it.


The shiners are patently not pooling estimates—the individuals are so bad at tracking gradients of light that it’s hard to believe that they’re making estimates at all. But by adhering to the simple instinct that keep them together as a shoal, the shiners can transform acts of individual detection into an act of group navigation.

That’s collective intelligence! The shiners’ ability to stay in shadeemerges from neighbourly interactions of dumb units. The fish aren’t pooling decisions that each individual makes on its own—they’re collectively processing information. By moving as one, they can compute as one.

Couzin suspects that this phenomenon is goes well beyond shiners, and might apply across a variety of migrating animals. After all, the rules that shiners obey are so simple that they should be a doddle for natural selection to produce. You don’t even need a brain to pull off the same trick—just the ability to respond to the environment, and to stay as a group. Cells can do that. All sorts of animals can do that.

This has implications for conservation.

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