Today, we look at the technology that first made us human. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.
You and I have talked much about how we're defined by our tools. Now let's ask, What were our first tools? Chimpanzees, even birds, not only select branches and twigs for use as tools, they shape them as well. Tool-making alone doesn't set us apart. So what distinguishes our tool-making from that of other animals?
A book by anthropologists Kathy Schick and Nicholas Toth, Making Silent Stones Speak, offers an answer. They remind us that the first humanoid apes walked the plains of West and South Africa on their hind legs over four million years ago. About two million years ago that beast's brain began to expand.
Just before that, about 2.4 million years ago, the first stone implements appeared. And they appear to be what marked our departure from other species. They mark us as tool-makers. If we're to understand ourselves, we need to understand those crude stones.
It takes a trained eye to see those ancient artifacts as tools. No delicate arrowheads or harpoons here. No recognizable ax heads. These are largely round rocks with pieces chipped out of them. What were they used for -- scraping, hammering?
So scholars take to the forest to see how such tools might've been used. Photos show anthropologists flaying meat from dead animals, separating bones, sharpening sticks and scraping hides. Gradually they learn what our two-million-year-old ancestors must have done with each type of tool. As they do, the sophistication of these chipped rocks becomes clear.
And what about the stone tool as weapon? Who can forget the first scene in the movie 2001? For Stanley Kubrik, we became human when apes on some antediluvian desert found they could use a bone to kill other apes. In fact, we find little ancient evidence of manufactured stone weapons -- or of bones used as tools. The Stone Age Cain may've slain Abel, but these new technologies were generally used for far better things than fratricide.
The authors show how the earliest stone tools did what other animals could do. A digging stick copies an aardvark's digging feet. A meat scraper imitates a saber-toothed tiger's flesh-cutting teeth, and so forth. And in that we see our emergence as a single species capable of replicating the functions of other far more specialized animals.
Shaping stone was, for all its seeming simplicity, a huge departure for our species. When we really see how sophisticated it was, we're less surprised that larger brains followed stone tools. As anthropologists take the trouble to experience the mind-expanding rush of recreating our first technology, they see why we went on to become something so different -- from any other primate.
I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.
Schick, K.D., and Toth, N., Making Silent Stones Speak: Human Evolution and the Dawn of Technology. New York: Simon and Schuster, 1993.