I was reading the Hundred Monkey posts from last month. You can find many instances in history to support the theory. Some of the breakthroughs mentioned are pyramids, the calendar, and time. Each of these breakthroughs was made contiguously in many parts of the world with seemingly no outside influence. I think though that you can find as many (if not more) instances, in the developmental history of man alone, where this "collective" knowledge theory is not supported. The greatest one that comes to my mind is that of metallurgy. Most of Europe and Asia had made great advances in metallurgy while Africa, Australia (Aboriginal), and the Americas still used tools and weapons of stone. At that, and with exceptions of course, these less technologically advanced societies were still stuck in hunter/gatherer mode. There was no collective consciousness driving these people towards enlightenment. Therefore, it would seem logical to suppose that if two groups of a species, who have no contact with each other and who possess a similar base of intelligence, were posed a problem at roughly the same time, each group would stumble upon a solution at roughly the same time.