"Many people have some level of colour deficiency but an island (Pingelap, a tiny atoll in the Pacific) where a tenth of the population is totally colour-blind gives us some fascinating insights, writes Michael Mosley."
"Although being colour-blind on a bright, sunny Pacific Island has a lot of drawbacks, there is one advantage. When the sun goes in, Herrol is finally in his element. He can see well, really well, in the dark.
No-one knows why, but it could be that the part of Herrol's brain that normally interprets bright daylight is now being used as extra processing power for his monochrome night vision.
So when it gets dark, Herrol and his friends get in their boats and hunt flying fish. They hang up flaming torches and the fish are attracted to the flames like moths to moonlight. It's in circumstances like these that Herrol can put his disadvantage to good use."
http://www.bbc.com/news/magazine-34346428