Northerners` brains are bigger, scientists find
Baku, July 27 (AZERTAC). Unfortunately, that doesn`t necessarily mean you are more intelligent than people from the south - just that you have evolved to cope with the longer winters and greyer skies in northern climes.
A study of populations across both hemispheres has shown people from countries further from the equator have more grey matter and larger eyes than those from sunnier parts. This is because living in low light conditions means the eyes and brain need to work harder in order to process images to a good level of detail, or “high resolution”. Researchers said the findings could theoretically even apply to different communities within a particular country, meaning people in the north of Britain might have larger brains than those in the south. Northerly populations have evolved to cope with dull, cloudy skies and short periods of daylight since migrating to Europe and northern Asia as many as 40,000 years ago.
Analysis of 55 skulls from 12 countries, dating from the 1800s, showed that people in northern areas have evolved to grow larger eyes and visual areas of the brain. Having wider pupils allows the eyes to take in more light, while a bigger retina is able to distinguish more detail, producing a higher-resolution image. A larger optic nerve and a more sizeable area of the brain dedicated to processing sight are also needed for northern populations to see to the same level of detail as people from further south. Researchers from Oxford University examined the volume of eye sockets and brain cavities in the skulls and found a direct link to the latitude of their country of origin.
While English people had an average brain size of 1,416ml, the figure in Micronesia, which lies very near the equator, was just 1,200ml. In contrast Scandinavians, the most northerly population tested, had a brain capacity of 1,484ml - more than 20 per cent higher than Micronesia. A similar difference was seen in eye volume, with English skulls indicating an average of 26.22ml, compared with 26.83 in Scandinavia and 21.83 in Micronesia. Eiluned Pearce, a postgraduate student who led the research, 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.
The study took into account the fact that people living in more northerly areas are generally bigger overall and the possibility that eye socket size could also be linked to the need to have more fat to insulate the eyeball in cold weather. Other research has shown that birds which sing earliest in the dawn chorus have relatively bigger eyes, and animals which are nocturnal have larger eyes than those that eat and forage during the day.
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