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 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.
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