[ianbicking]

Punctuated evolution doesn't mean that evolution was fast, at least as I see it: instead evolution has solved problems in the past and created latent capabilities that can be rapidly engaged through small mutations or epigenetic changes like hormonal changes that get passed on generationally through early development.

That is to say that while humans developed higher intelligence over a relatively short time, that was created from a novel combination of evolutionary abilities rather than a novel evolutionary invention.