Unbound: How Eight Technologies Made Us Human and Brought Our World to the Brink

by Richard L. Currier

With the waning of the ice ages and the warming of the earth, humanity was about to embark on its next great metamorphosis. Each of the four metamorphoses that had already taken place had transformed the biology of our ancestors in significant ways. The technology of spears and digging sticks transformed us from quadrupedal into bipedal animals. The technology of fire and cooking resulted in the loss of our body hair, a massive expansion in the size of our brains, and the disappearance of our tree-climbing anatomy. The technology of clothing and shelter enabled us to migrate out of the tropics and made it possible for our “premature” newborns to survive in cold climates. And the technology of symbolic communication involved significant changes in our brains, freeing us from the slow pace of biological evolution and enabling us to take advantage of the speed and flexibility of cultural evolution.