Human Brain Evolution Was a 'Special Event'

Chaos theory probably explains it - I' not an expert, but...If you drop a plate and it breaks you get a few big bits and lots of medium sized bits and loads of tiny bits (and millions of teeny bits). Ice ages and other natural events exhibit this phenomenon, which I think is called "scale-free" phenomena. So, a concentration of mutations in a few generations is not astounding, and may be seen as special if one chooses to see it that way.