archaeology.org 43you can take a quantum leap back in time into the mind of a
person,” Woods says. “It’s problem-solving, fossilized.”T
he earliest recognizable stone tools appear 3. 3
million years ago. They’re nothing more than rocks
smashed together, with the resulting sharp chips and
splinters used as crude cutting tools. “There’s not a lot of
deep thought going on,” says Putt. Chimpanzees in captivity
use similar techniques to this day.
Beginning around 2. 5 million years ago, something started to
change. Hominins began refining their technique by fashioning
rocks themselves into cutting tools. These shaped stones—
named Oldowan tools after the storied Olduvai Gorge, an area
in Tanzania that has yielded ample evidence about our distant
ancestors—don’t look like much. “Most people, if they’re
unfamiliar with stone tools, would pick up something from the
Oldowan and not realize it was tampered with,” Putt says.
For archaeologists, however, the Oldowan represents a
glimmer of something more complex, a decisive step forward.
“They’re holding them in their hands and precisely aiming
them at hammerstones,” rounded rocks that toolmakers used
to chip flint, Putt says. “The creatures making Oldowan tools
were very intelligent, but I don’t know if we would think of
them as human.”
Things began to shift again around 1. 7 million years ago.
Beginning in Africa and spreading into Europe and Asia, the
Oldowan gave way to something altogether different. Early
hominins began making clearly identifiable hand axes. Some-
times called bifaces, they’re teardrop-shaped chunks of stone
between four and eight inches long. They can range from rough-
hewn to refined, but they’re clearly purposely shaped tools.What stone toolmaking and
neuroscience can tell us about
what it means to be humanby Andrew Curry
These practical, versatile tools, first identified in France in
the nineteenth century and called Acheulean after the village
of Saint-Acheul, represent a significant leap forward. The
tools’ shape and complexity required their makers to think
several steps in advance. These were the first flintknappers,
people who deliberately shaped raw pieces of flint, or cores,
into tools by applying pressure to the stone. “They start to
think about the shape of the core, not just the flakes,” Putt
says. The sharp flakes chipped from the core could also be
used as tools. The flakes were used to cut, scrape, pierce,
and kill, and were the mainstays of human tool use until the
invention of metallurgy. Acheulean toolmakers sought out
specific types of stone, sometimes traveling for miles look-
ing for the best raw material, carrying large pieces over long
distances, and then using them to make smaller tools.
Watching dozens of volunteers struggle to make hand axes
during her Ph.D. project convinced Putt that Acheulean tool-
making took more than muscle memory, animal instinct, or
luck. “You have to be able to reimagine what the end product
might look like once your dreams are shattered,” Putt says
about the effect of a misplaced blow. “‘I have a vision of what
I want this to look like, but, oh crap, I split the core, and now
I have to revise my vision.’”
This kind of planning, learning, and control probably
required boosted brain power—something fossilized skulls
show hominids were developing during the Acheulean.
“There’s a doubling of brain size, and more human-like pro-
portions in the body,” Putt says. “It seems like there’s so much
going on—changes in stone tools, in brain size, in body size,
and human ancestors are leaving Africa to explore different
parts of the Old World.”