My, What A Big Brain You Have!

Aug 1, 2011 By Arati Rao
Arati Rao's picture

My, what a big brain you have!  My, what large eyes you have! No no, we are not enacting the fairy tale "Little Red Riding Hood" here. We are quoting from a recent study that finds that your brain and eyeball size related directly to how far away from the equator you live!

Oxford anthropologists, led by Eiluned Pearce measured eye sockets and brain cavities of skulls from the 1800s. They used populations from all over the world and what they have found is this: there is a relationship between size of the brain and eye socket and where one lives.

People from the northern latitudes – especially Scandinavia, had the largest brains and eyeballs, while those from Micronesian islands had the smallest. But, wait – before you jump to any conclusions, larger brains do not necessarily mean more intelligence! 

The brain is a fascinating organ. Why? Well, man has colonized these higher latitudes only for a few tens of thousands of years and the brain has already adapted to those extreme conditions.

What conditions do we speak of? Well, the sunlight is lesser in those latitudes  and to cope with low light conditions and cloudier skies, the eyeballs need to be bigger (to gather more light) and the brain area of visual processing (visual cortex) needs to evolve more too. This is essentially what has happened with people living in higher latitudes. 

Moreover, a similar phenomenon is seen in animals where nocturnal (active at night) animals tend to have larger brains and eyes in proportion to their bodies, in order to see better, than their pals who function in the daytimes and sleep at night. Does this mean that people with larger eyeballs and brains can see better at dusk or when light is very low?

A-ha. There is never a dearth of questions to explore and the anthropologists are onto that one next!

Here is the first of a 4-part series on the Human Brain: