<HTML>Hi Don,
Alas we may never really know the answer to this one with any certainty. Perhaps all we can hope for is to be able to identify and date the products of cognitive intelligence in the archaeological record; tools, art etc. Though even then the evidence itself will be patchy and the picture that emerges incomplete.
As for the cause of the 'spark', I would tend toward the asumption that intelligence was driven by evolutionary pressures, insofar as it aided the survival of those blessed with it. I suppose this would mean that it was a gentic fluke of sorts to begin with. I'm way too out of my depth on this one to speculate about whether we were given brains which we then learned to use or whether the use itself led to the development of the brain. Maybe a bit of both?
Regards,
Derek</HTML>
