18th Feb 2010; 13:00

Please right-click button and choose "Save Link As..." to download audio file onto your computer.
Did you know that you have just 150 friends, acquaintances and relatives? And that this is a natural size for villages all over the world? Now known as ‘Dunbar’s Number’, it defines the feasible boundaries of our social lives. Dunbar’s investigations show us that we inherited the social side of our brains from our mother, and the emotional side from our father; why many women see the world in four or even five different colours, but men only ever have the conventional red, green and blue; and why facial symmetry has everything to do with voter choices in elections.
Chair: Matthew Taylor, chief executive RSA
Suggested hashtag for Twitter users: #rsafriends
You are welcome to link to, download, save or distribute our audio/video files electronically. Find out more about our open access licence.
There are no books.