Click here for audio of Episode 1109.
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
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.