ABC Radio’s Science Show just had a special edition on the evolution of the brain and the development of social intelligence.
The programme talks to some of the leading researchers in social intelligence whose research interests range from comparing the behaviours of animals across species, to neuroimaging humans, to building robots to mimic social interaction.
In particular, the programme tackles the ‘social intelligence hypothesis’ that suggests that our increase in brain size during evolution has been driven by the need to work in groups and make sense of complex relationships.
Prof Steven Mithen explains:
There seems to be two key figures of brain expansion, and I think this is where the social intelligence hypothesis becomes very interesting. The first was around two million years ago, and at that time brains expanded perhaps about 50%. So we went from brain size of around 450cc to a brain size of around 1,000cc by 1.8 million years ago. What’s interesting during that time is that we don’t see dramatic changes in human behaviour as represented by the archaeological remains….
So archaeologists asked; why are brains getting larger and what is it providing? Brains wouldn’t get larger just for any reasons because brain tissue is metabolically very expensive, so it’s got to be serving a really important purpose. I think the social intelligence hypothesis suggests to us that that expansion of brain size around two million years ago was because people were living in larger groups, more complex groups, having to keep track of different people, a larger number of social relationships which we simply required a larger brain to do.
Link to Science Show special on ‘The social intelligence hypothesis’.