High population density triggers cultural explosions

An interesting article over at e! Science News, High population density triggers cultural explosions from June 4th, 2009.

High population density leads to greater exchange of ideas and skills and prevents the loss of new innovations. It is this skill maintenance, combined with a greater probability of useful innovations, that led to modern human behaviour appearing at different times in different parts of the world.

It would appear to be analogous to the reading research we are finding that volume of books read and access to books are key determinants to yet further improvement in reading capability.