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About the Royal Society

It's dim up North

27 July 2011

Research published today in Biology Letters reveals that people living in Northern countries with dull, grey, cloudy skies and long winters have evolved bigger eyes and brains so they can visually process what they see in the gloomy light conditions.

Scientists from Oxford University measured the eye socket and brain volumes of 55 skulls from museum collections, representing inhabitants of twelve different countries from Scandinavia to Micronesia. The volume of the eye sockets and brain cavities were then plotted against the latitude of the central point of each individual’s country of origin.  The researchers found that the size of both the brain and the eyes could be directly linked to the latitude of the country from which the individual came.

Lead author Eiluned Pearce said: ‘As you move away from the equator, there's less and less light available, so humans have had to evolve bigger and bigger eyes. Their brains also need to be bigger to deal with the extra visual input.  Having bigger brains doesn't mean that higher latitude humans are smarter, it just means they need bigger brains to be able to see well where they live.’