William Calvin's book A Brian For All Seasons: Human Evolution and Abrupt Climate Change makes a bold suggestion: Climate change shaped the evolution of the human brain.
Calvin writes that harsh cold weather might have required early human beings to cooperate rather than compete for survival, and in the process shaped the structure and functionality of the human brain.
In this report, former associate director of the Center Paul Epstein writes a compelling commentary on Calvin's book, and praises it for attempting to unravel "just how Earth’s convulsive history helped shape the way we think, talk, organize ourselves, and question, observe, and analyze everything around us."
Epstein also makes a strong argument for the integrative sciences in this review. "Such integrative thinking might even contribute to a sudden shift in consciousness — and to the up-regulation of the cooperative and intelligent behavior that was so effectively expressed at other desperate times in not so distant eras," he writes.