Rating is available when the video has been rented.
This feature is not available right now. Please try again later.
Published on Dec 5, 2012
More about this programme: http://www.bbc.co.uk/programmes/b01p9l1j We've all got one, and some of us even use it, but throughout history the grey matter between our ears has puzzled even the brightest minds.
From Episode 5 of Dara O Briain's Science Club on BBC Two.