I'm an archeologist,
but I didn't start out that way.

In fact, as a kid, I thought
I was going to be an engineer,

and I liked to take things apart

and sometimes
put them back together again.

But, when I was growing up,
I started to see parts of the world

that I couldn't quite explain
from an engineering perspective,

which tends to focus on how things work
rather than why they are.

I saw things that were Indian mounds,

mounds made by prehistoric people,

that you find out
in the woodlands of Wisconsin.

And some of these mounds
are pretty spectacular.

For example, this mound here
is an effigy mound,

shaped like a gigantic bird.

It was made by a prehistoric people,
by their community.

They got together to make
this bird-shaped feature,

and there were
some burial components to it.

And it made me wonder,
"Why would people do this?

Why in this place, at this time,

did they get together
to build these mounds?"

People didn't build mounds all the time
and they didn't build them everywhere.

In fact, the effigy mounds,
99 % of them are in the Wisconsin.

Why would you build
an effigy mound in Wisconsin?

It's cold.

You know, why not do
something else, like get food?"

So, it really made me wonder,
"Why would people do this?"

And I started to see the world
and learn more about it.

There are a lot of places and times
when people got together as a community

to build really spectacular things
around the world.

We see this in North America,
we see this in Europe,

we see this in South Asia.

All around the world we see
these spectacular monuments.

And it made me wonder,
"Why do people build monuments?

Why did they get together at certain times
and places, as a community,

to construct these things?

What's going on here?"

Because, in some ways,
they're kind of weird, kind of crazy.

Isn't it better to, you know, focus
your energy on survival, food,

in reproduction?

But people do this.

So, really, it seems to be
an important question

because some of the things they do

are some of those spectacular cases
of prehistoric activity that we know of,

really, achievements of humans.

And I thought also
that if we can figure this out,

if we understand the past,

we can also understand what were
the conditions that are necessary

that would encourage people
to get together to do this.

If we understand those conditions,

we can ensure in our population,

in our society,

that we have those ingredients

and that maybe we can get together to do
things that people in the future will go:

"Wow! That's really an impressive feat."

So, I thought this was actually
a way of looking at the past

and a way of looking at the future.

This set of questions
led me to leave engineering,

and, you know,

I quickly switched majors,

which didn't make my dad, who was
a professor of Engineering, very happy.

But...

It led me to a very different path
and I became an archeologist.

And as an archeologist,

as a professor at Cal State Long Beach,

I was given the opportunity
to study aspects of the world

that were interesting to me.

I chose one place that seemed
the most ridiculous of all:

Easter Island.

It's a tiny little island,

that is also known as Rapa Nui
in the local language,

that is in the middle of the Pacific.

It's 3.500 km from the mainland of Chile,

2.000 km from any other Polynesian island.

It's really a small island
in the middle of nowhere, and it's tiny:

it's only 24 x 12 km in size,

a really tiny little island
in the middle of the Pacific.

But yet, on this teeny-tiny island

we find some of the most spectacular cases

of prehistoric monument construction
anywhere in the world.

In the most improbable place,
we have just amazing archeology.

And this archeology is pretty famous:

the statues that were made there
are known as "Moai,"

and these statues range
from, you know, a couple of meters

to nearly 10 meters in height,

they weigh up to 70 tons of stone

and they were put on top
of massive platforms known as "Ahu."

It's some of the most
spectacular archeology,

They're just amazing
in this tiny, tiny place.

What's going on here?
Why would people do this?

Well, a lot of people know
about Easter Island

because of the monuments,

and the story that
has grown up around them.

And that's been made
very famous and popular

by Jared Diamond in his book "Collapse."

In this book he argues that
these statues are actually responsible

for the demise of the population,

rather than an achievement of theirs
that helped them succeed.

This "Collapse" story goes like this,
in five easy steps:

Initially, there was
a palm forest on the island,

and we know that,
we can look to the botanical remains

and we can see the evidence
of a massive palm forest

that once existed there.

We think people get there
about the 13th century,

and they start to do what people do,

which is: clear some land,
have more people...

What human communities do is grow.

While they're doing that,

they, at some point, start to make "Moai."

And Moai construction in this island
isn't something that you do "one of,"

which would be amazing.

But they start do make
more and more of them

and they get larger and larger

and there's a thousand
of statues on the island,

to give you a sense of
what incredible investment of energy

they're focusing on this.

In some ways, you can imagine
it could be a "Moai" mania,

people want more and more "Moai,"

and they would do it
regardless of the consequences.

And it is really that sort of disregard
for the environment,

that is thought to be resulting

in the destruction of the resources
there on the island,

particularly the palm forest.

The ecological destruction ultimately
leads to people having shortage of food,

and that leads to warfare

and ultimately tales of cannibalism.

And this is really
the core story of "Collapse"

and the result is, of course,
societal collapse.

And we can see that,
or Europeans saw this:

when we look on the landscape,
we find fallen down statues, no trees,

sort of the remnants
of what potentially was a great society,

but the Moai did it to them.

And it's the key sort of relationship
between this Moai construction

and this failure
that drives this collapse story.

Moai mania causes a "downward spiral
of cultural regression",

in the words of some authors.

Well, that's the mindset I had
when I first went to Easter Island,

when I was given the opportunity
to study there in 2000.

I travelled to this island

and I wanted to do
fieldwork to figure out

why would people do this.

People certainly didn't get there deciding
they were going to destroy their island.

They got there,
and being successful people,

moved there to find new lands,
and to have families,

and build communities.

So, I went to the island
and started studying the statues,

to understand a little bit
how they were moved,

what kind of size communities must
have been involved with making these.

But I also did excavations
of the earliest occupation of the island,

with the goal of seeing what were people
eating and how were they living

when people first got there.

Obviously, they didn't have
the "Moai" mania about it,

so I wanted to see
how that changed, ultimately,

into this path of destruction.

I also looked across the landscape,
I did survey work,

and looked at where Moai are

and where they're distributed
in the landscape,

how communities live,

where people are living,
where the houses are, etc.,

to understand the overall society
in the community of prehistory.

And what I found after doing
10 years of work there

was something that really surprised me.

I had no idea this
was going to be the case,

and it still is controversial to today,

but, fundamentally, the case is:

there really is no evidence whatsoever

to support a prehistoric
demographic collapse on Rapa Nui.

It's kind of shocking.

You'd be thinking: "Of course there is;

that's the whole story and premise of it,
everyone knows that."

But, in fact,
when we look on the ground,

we don't see any evidence that says
that there was a big war

and that the island destroyed itself.

We see something quite different.

We can look at things that people say
are aspects of warfare.

We can look at the "mata'a"
which are obsidian tools

that we find by the thousands
across the island.

And these are often said to be
weapons of mass destruction

that were involved with the warfare

where people used these
to kill each other.

When we look at these in detail,

we find not what we would expect
to see in lethal weapons,

which are pointy things
that we would use to stab people,

or things that are effective
at killing people.

Instead, we find really irregular devices

that wouldn't do much
in the way of stabbing anything.

And we find use-wear on it,

patterns of how those things
interacted with the ground.

It's consistent with cultivation.

So, rather than being weapons
of mass destruction,

what we're really seeing is the remnants
of people cultivating plants

and using the landscape;

so, the opposite
of what the stories often told.

One of the things that is going on here

is that I think some of this
prehistoric collapse idea

comes from a confusion about
what happened after Europeans get there.

What we know and we have
good documentation of

is that in the 18th century,

European contact resulted
in catastrophic demographic collapse.

And it is really well documented.

We have lots of historic records
that point to the fact

that Rapa Nui people interacted
with the Europeans that arrived,

and that disease was passed
from the Europeans on to the Rapa Nui

and the Rapa Nui people died
in large numbers,

a really catastrophic history.

That happened in many places,

in many islands,
in many parts of the world,

due to the differences and histories
of Europeans and Polynesian people.

We can look at story records
to see really directly the impact of this.

In 1722,

Jacob Roggerveen, who was a Dutch captain,

was the first European
to arrive on the island.

When he gets there,

he estimates somewhere about
3.000 people on the island

and he describes them
as healthy and robust.

They're doing very well,
and they're 3.000, or so.

After that, we start to see
smaller and smaller numbers.

The Spanish Captain Gonzalez
sees about 2.000,

Cook sees even fewer,

and the numbers over the next century,
or so, get smaller and smaller and smaller

until 1877,

when there are just 111
Rapa Nui people alive on the island.

The population goes from 3,000 healthy

to 111 that are riddled with disease
and really struggling for survival,

and really all the people living
on the island today

are all descendent
from these 111 people.

We have good records of that,
so we know that happened.

And we can also see the effect
that these diseases had on the landscape

and that often is confused

as being somehow connected
to this prehistoric collapse.

A lot of times, people would say:

"Of course there was
a prehistoric collapse!

We can look on the landscape
and the statues are all fallen down

because people were fighting each other
and knocking each other's statues down,

and that's in oral traditions,
and we know that.

Of course there was a collapse."

Well, when we look carefully
at the story record,

we see a very different story.

Jacob Roggerveen,
when he was there, in 1722,

he doesn't describe
a single toppled statue.

Instead, he describes statues
all standing up.

In fact, there are drawings that he made

-- and early European Explorers --

of standing statues,

and they describe how tall they are,
and they measure them.

So, initially, we don't see
any toppled statues.

Gonzalez, also, 50 years later,
doesn't see any toppled statues at all;

he describes all the statues as standing.

Cook, though, on the other hand,
starts to see toppled down statues.

He starts to describe the fact
that some statues are standing

and the other ones
are laying on the ground, broken.

He sees skeletons and other things
that looked like destruction,

so, a lot of our ideas about this collapse
comes from his observations.

But, over time, we see
fewer and fewer standing statues,

and more and more statues
that have fallen down

and are on the landscape.

In fact, by 1868,

the British noticed that there was not
a single standing statue.

Any statue that you see today
was stood back up after 1950.

So, after 1868,
there wasn't a single statue.

So all of the evidence that people
talk about as being fallen statues,

as therefore evidence
of warfare and collapse,

is simply the result
of population loss due to disease,

and changes in the economics,

that people are no longer
investing in statues.

So,it's an European event,
it's a historic event,

not something prehistoric.

We also see, when we look
at the survey work,

that there probably was never
a very large population.

A lot of the assumptions about collapse
is that Roggerveen saw 3.000 people,

and Europeans say: "There must
have been a lot more people.

There's nearly a 1.000.

It must have been
maybe 10.000 20.000 people."

So, when Roggerveen sees 3.000,
really the population had already declined

and what we are seeing is the remnants
of a much greater population."

Well, great, OK, but when we look
at the archeological record,

we really don't see that evidence.

Take the south coast
of the island, for example.

We're doing some survey work.

When we focus on the south coast,

what we don't see
is evidence of large villages

where people are densely living,

with the landscape around it
being intensely used

for cultivation to support
that large population.

Instead, what we see

is a low-density distribution of material,
and features and household debris.

That represents a population or society
living across the landscape

in a low-density way;

relatively small numbers of houses,
distributed across the island.

These people are using the landscape
in an extensive way,

rather than very intensively.

So the archeological record
just doesn't simply point

to the kinds of evidence
that would support a large population.

It used to be something
very, very different.

We also now know
that the environment of Rapa Nui

was never particularly great.

The soils themselves are actually
very depleted, are very low in nutrients,

naturally because they're
very weathered soils.

So the result was that the resources
that people needed to survive on

were never that particularly fantastic,

people had to live in an ingenious way.

What they did, which is pretty amazing,

was enrich the soil by using
lithic mulch gardening.

Lithic mulch gardening consists
of taking pieces of fresh bedrock,

breaking them up into pieces

and laying them on the surface
of the ground, and in the ground,

in order to expose the soil
to new nutrients, to new minerals.

And that allowed the soils
to have enough productivity,

just enough productivity
to reliably grow sweet potato,

which is the primary crop
of Easter Island.

So, instead of a rich environment
that gets destroyed,

we see people taking
a once treed environment

and turning it into a garden landscape

that allowed them to grow resources
that enabled them to survive.

And we look across the island,

and we look at rock mulch,
or this lithic mulch, across the island,

and we see it scattered extensively

similarly to what we saw
with the community evidence,

scattered extensively across the island,

in a sort of low-density capacity,

and it provided food in a reliable way

that enabled people to live there.

We also know evidence now,

that the statues didn't require
armies of people.

Certainly, some of the older ideas
about statue movement

which led to the idea
that there must have been a collapse,

is the idea of armies of people
and armies of other people

to support those armies of people
moving the statues,

because they're so heavy
-- how else could you do it,

but to have thousands of people
dragging these around.

When we look at the details
of the statues themselves,

and look carefully
at the evidence that exist,

we can see that there are
systematic differences between statues,

once they get to Ahu, the platform,

from the statues
that are found along the way

or on the way from
the quarries to the Ahu,

that these statues --
we called them Road Moai --

are quite different.

And they're different
in a very particular way.

They're leaning forward.

They're, in fact, tipping over.

They don't even stand up on their own.

Once they get to the platform, the Ahu,

in fact, the statues are changed,
they're modified by prehistoric people,

to make them stand up.

But in the roadways,

we find all the statues,
every single one of them,

leaning really far forward.

And they have a very peculiar base:

the base is very rounded
on the front edge.

And we think that what's going on here

is that the statues were moved
like gigantic refrigerators.

But even more so,
they were designed in such a way

that they could be moved
by small numbers of people,

in a standing-up position.

And all of the evidences that we find

in terms of how they're fallen,
how they're broken,

how they're constructed, how they fell,

all point to the fact
that they were standing up

and some of them fell down
during transport,

but many of them made it
to the Ahu and were changed

once they got there.

Now you might say:
"Well, it's a great academic story.

Maybe it's possible, maybe it's not."

But we wanted to go beyond that,

and so we made one.

We made a statue,
a five-ton version of a statue,

and we demonstrated that, in fact,
12 people can move a five-ton statue.

In fact, we were able to move
this statue a hundred meters

in about 40 minutes,

which suggests that we can move a statue
like this about a kilometer in a day.

So, what seemed to be something
that was this inhuman effort,

that took incredible amounts of energy,
and resources, and people,

was actually ingeniously designed statues

that were designed to take steps
and walk themselves down the roadways.

It's pretty incredible.

The statues literally go
from immovable ...

(Applause)

These statues go from immovable objects
-- I mean, they're incredibly heavy --

to something that is really
dancing down the road.

It's really mind-blowing

and it really opened my eyes to how
incredibly ingenious these people were.

So, instead of a record
of failure and terribleness

that people inflicted upon themselves,

what we see is success,

we see the success of Rapa Nui.

Rather than see this as tales of things
that we should avoid in the future,

we see a tale of 500 years
of persistence of people

on a remote and tiny island
in the middle of the Pacific

with very limited resources.

We see people who are making smart choices
that enable them to persist,

and not everybody
in all the Pacific actually made it

from initial colonization
to European contact.

Rapa Nui is sort of uniquely remote,
isolated and has that record of survival.

So, from there, I think,

rather than seeing Rapa Nui
as a case we need to avoid

and let's not do what they did,

we actually need to learn from them,

and there's a number of lessons
we can draw for ourselves

about the prehistory of Rapa Nui.

First, is the fact
that cooperation matters.

Cooperation on a tiny,
remote island is necessary.

And we can see on Rapa Nui

that cooperation
was inherent in this society,

because statues, the Moai and the Ahu,
needed groups of people to make

-- you can't move it on your own,
you need your neighbor.

And the fact that there is nearly
a 1.000 statues and over a 100 Ahu,

could indicate the importance
of these people getting together

to move these statues.

The cooperation is probably the key
to the success of them,

and the making, the construction
of these Moai and the transport of them

probably was an activity
that ultimately helped the community

rather than cause some failure.

They did it in a smart way,

small groups of people
getting together to cooperate,

and the sharing of the
resources and the effort

probably was something that really was key
in surviving on this tiny island.

We can also see
that diversity and innovation

are something we should really value.

The Rapa Nui people certainly
brought statue construction with them

as other Polynesians brought statues
and monument construction with them

on other islands,

but on Rapa Nui, statue construction
became incredibly important.

It happened to provide
the right mechanisms,

the right ingredients,

that enabled the society
to be stable and persist over 500 years.

For ourselves, we need
to think about the fact

that you wouldn't have guessed

that statue construction would have been
so important on Easter Island.

It was one of the many things
that they were doing,

and it just happened to be
the right thing.

Now, there's probably in ourselves,
in our own society,

many things that we're doing today
that we don't know

are going to be critical
for our success in the future.

So, since we don't know exactly
what's the recipe for the future,

we do always encourage diversity
and innovation whenever possible,

because some of those things that we do,
that we may think are crazy,

at any point of time,

may be things that help us
survive going forward.

Lastly, we can see
that the Rapa Nui people,

by virtue of being on this island
that is so remote,

had to think local, local, local
in everything that they did.

They were forced to,
they couldn't go off to some other island

when they run out of food,
and pop over to get some stuff.

They had to live on the island

and survive every kind
of environment that it experienced,

and they did so
by structuring their society

and their cultivation
and their organization,

such as they could survive
using what they had available,

that was locally available,

and that allowed them to persist.

They weren't subject
to external events happening,

or trade connections failing.

They had everything they needed,

by virtue of having to be there,

and they survived.

In the same way, we need
to think about that ourselves.

It's often easier to sometimes rely
on long-distance things,

that give us immediate success,

but probably put us
in more peril, in the long run.

Because we start to add on more risk,

because we're dependent
upon more distant kinds of resources.

So, in the end,

my interest in archeology
kind of led back to engineering.

As I started to figure out

how these monuments
and how this society worked,

it sort of got me back to engineering.

And from this evidence,
we can see the statue construction,

while it might seem
like a peculiar and curious thing

and kind of crazy,

is in fact, likely,
the key to their success.

The secret to how they did this
is embedded in the things

we think are crazy

but are perfectly sensible
to the people that were there.

And we have the evidence
that demonstrate that,

as they persisted
for 500 years in this tiny island.

So, I think there's a lot
to be learned from the past.

We often think about the past
as some idiosyncratic story

that happened in the past,
and who cares,

but, in fact, all the lessons
about how change occurs

and what's necessary for long-term
persistence exist in the past,

and we have much to learn about that.

Thank you.

(Applause)