Making Stone Tools | Big History Project

My name is Nicholas Toth. I am the co-director
of the Stone Age Institute and a professor of anthropology
at Indiana University. And I want to show you
what our ancestors started doing about two
and a half million years ago, that we can see
on the African continent. The earliest
archaeological record are very simple stone tools, and
they discovered around this time that if you took
two natural cobbles, say from a gravel bar
of a river, you could hit one
against the other one… and knock off these razor-sharp
pieces of stone that archaeologists
call flakes. So in a matter of a few seconds, I am producing these very sharp
razor blade-like materials… that can be used for,
say, cutting up the carcass of an animal
that you might kill or maybe you find
that’s been left by carnivores and a little bit of meat
left on the bones that you can cut off. So these are literally
razor sharp. If I were to drag this
across my finger, I would cut
myself quite badly. So, when you think
of early stone tools, don’t think that they’re not
razor sharp. They are as sharp
as a surgical scalpel. And we can use these
for a range of activities as our ancestors did
in the early Stone Age, butchering animals,
working wood. Say you want to make a spear
for hunting or a digging stick for digging
up roots and tubers from the branch of a tree. These are great tools
for the shaping that you would do for that. And so we see this trajectory
in human evolution starting around two and a half
million years ago of these very simple types
of stone tools. And it is soon after that,
by about two million years ago, that we have really good
evidence for the expansion of the human brain, for the spread out of Africa
shortly after that, the reduction in the size
of the teeth and the jaws of our ancestors as well. And starting about one
and a half million years ago, they started
getting more ambitious and making forms that we call…
so-called hand axes. They were probably held
in the hand and used as cutting tools. This would be one,
it’s a more refined one from perhaps about a half
a million years ago or so, made out of flint. And so the idea of
this is, you would take a larger piece of stone and kind of imagine that form
in the middle of it and then again using a hammer
slowly but surely, marching around the edges
and knocking off flakes. So, I’m using the scar
of the flake that was just knocked off
as a striking platform to go in the other direction. And the idea is,
you want to march all the way around this piece. So, I’m not thinking too much
about the final shape yet. I’m just kind of
trying to produce an edge… around the circumference
of this piece. Okay, and so it would take me
about another five minutes to go all the way around this. And then the next stage that
our ancestors learned to do… that’s called
hard-hammer percussion, where you use a hard hammer
to knock off flakes. And another thing
they learned to do, which is really interesting
and somewhat counterintuitive, is you totally steepen the edge, you dull the edge by removing
these little flakes with a smaller hammer and then grinding the edge. And then you take
a softer material. It could be a piece
of hard wood, a fragment of elephant tusk… In this case I’m using
an antler of a deer. And you’re biting
right into the edge… and you’re able to remove
much longer, thinner flakes when you do that. And this is a way
of controlling flaking. I’ll do it one more time. And you get a much thinner
product at the end of it. And this is called
soft-hammer technique. So, I’m going to try to drive
a flake off of this side by striking on this side. See how I did that? And by doing that, going around, you can carefully
shape the edge, thin it, and make a superb butchery tool. And when people ask,
why did they bother to make something this big? They were butchering
large animals, sizes of zebra and buffalo on occasion. These are big mammals that weigh hundreds
and hundreds of pounds. And would you rather use a razor blade for butchering
one of these animals or would you rather use basically a two-fisted tool
like this? You have a lot more
cutting edge, a lot more weight behind
what you’re doing as well. And so when we look
at the history of technology, you’re seeing changes
in the refinement of stone tools over time. By the time you get
to Neanderthals and early modern humans,
they’re probably starting to haft tools onto handles, either using some kind of
adhesive material like pitch from a pine tree or by using sinew
or other material to lash tools together as well. And so we see this progression
and refinement of technology through time,
especially with stone, but starting around
80,000 years ago. We’re also seeing refinement
in bone working, that they’re starting
to make bone tools for the first time as well. And we strongly feel
that technology is a very important element in the evolution
of the human brain, that without technology we wouldn’t have the high
quality diet that we need that’s driving
that brain evolution. Your brain is about three
percent of your body weight but about 20%
of your energy intake. So it’s a very expensive
organ to have. So we must have had
a very good reason to have a large brain. It probably has to do with becoming
very social animals. We’re living in larger groups. We have to deal with
a number of individuals politically and socially, and so more intelligent animals
are able to interact socially in a better way. And so, probably another payoff
of these larger brains over time is that we become more
inventive and experimental and try new techniques of making and using
tools as well. And we become the consummate, the most important
dedicated toolmaker in the history of the Earth,
as we are today.

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