Today I Learned (TIL)

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TIL about Tetrachromacy, a condition which lets you see more colors. Normal people can see about 1 million colors, while tetrachromats may see up to 100 million. Up to 12% of women may have it. (www.healthline.com)

submitted 11 months ago by [email protected] to c/[email protected]

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[–] [email protected] 1 points 11 months ago

Tetrachromacy is real, and does improve the range of colour differentiation in people who have it, but the headline here greatly exaggerates the degree to which that is true.

https://www.youtube.com/watch?v=fDoAs0qN7lU

The title is predicated on the idea that 1 cone = 100; 2 cones = 100^2^ = 10,000; 3 cones = 100^3^ = 1,000,000; so having 4 cones = 100,000,000. But this is misleading, because once you have three kinds of cones, any point within the visible range has its own unique response. The 4th cone improves the ability to make fine differentiations (the examples in other comments here are fantastic demonstrations of that), but doesn't add entirely new colours.

Sort of like how 3 towers are enough to triangulate someone's location on a map. A 4th tower might make the triangulation go easier, or give you more confidence in your result, but it doesn't fundamentally alter your understanding.