The surprising decline in violence

Steven Pinker charts the decline of violence from Biblical times to the present, and argues that, though it may seem illogical and even obscene given Iraq and Darfur, we are living in the most peaceful time in our species' existence.

Images like this, from the Auschwitz
concentration camp,

have been seared into our consciousness
during the 20th century

and have given us
a new understanding of who we are,

where we've come from
and the times we live in.

During the 20th century,
we witnessed the atrocities

of Stalin, Hitler, Mao, Pol Pot,
Rwanda and other genocides,

and even though the 21st century
is only seven years old,

we have already witnessed
an ongoing genocide in Darfur

and the daily horrors of Iraq.

This has led to a common
understanding of our situation,

namely, that modernity
has brought us terrible violence,

and perhaps that native peoples
lived in a state of harmony

that we have departed from, to our peril.

Here is an example
from an op-ed on Thanksgiving,

in the "Boston Globe"
a couple of years ago,

where the writer wrote,
"The Indian life was a difficult one,

but there were no employment problems,

community harmony was strong,
substance abuse unknown,

crime nearly nonexistent.

What warfare there was between tribes
was largely ritualistic

and seldom resulted in indiscriminate
or wholesale slaughter."

Now you're all familiar
with this treacle.

We teach it to our children.

We hear it on television
and in storybooks.

Now, the original title of this session
was, "Everything You Know is Wrong,"

and I'm going to present evidence

that this particular part
of our common understanding is wrong,

that, in fact, our ancestors
were far more violent than we are,

that violence has been in decline
for long stretches of time,

and that today, we are probably
living in the most peaceful time

in our species's existence.

Now in the decade of Darfur and Iraq,

a statement like that might seem somewhere
between hallucinatory and obscene,

but I'm going to try to convince you
that that is the correct picture.

The decline of violence
is a fractal phenomenon.

You can see it over millennia,
over centuries, over decades

and over years,

although there seems
to have been a tipping point

at the onset of the Age of Reason
in the 16th century.

One sees it all over the world,
although not homogeneously.

It's especially evident in the West,

beginning with England and Holland
around the time of the Enlightenment.

Let me take you on a journey
of several powers of 10 --

from the millennium scale
to the year scale --

to try to persuade you of this.

Until 10,000 years ago,
all humans lived as hunter-gatherers,

without permanent
settlements or government.

And this is the state that's commonly
thought to be one of primordial harmony.

But the archaeologist Lawrence Keeley,

looking at casualty rates
among contemporary hunter-gatherers,

which is our best source of evidence
about this way of life,

has shown a rather different conclusion.

Here is a graph that he put together,

showing the percentage
of male deaths due to warfare

in a number of foraging
or hunting and gathering societies.

The red bars correspond
to the likelihood that a man will die

at the hands of another man,

as opposed to passing away
of natural causes,

in a variety of foraging societies
in the New Guinea highlands

and the Amazon rain forest.

And they range from a rate of almost
a 60 percent chance that a man will die

at the hands of another man

to, in the case of the Gebusi,
only a 15 percent chance.

The tiny little blue bar
in the lower left-hand corner

plots the corresponding statistic
from the United States and Europe

in the 20th century,

and it includes all the deaths
of both World Wars.

If the death rate in tribal warfare
had prevailed during the 20th century,

there would have been two billion deaths
rather than 100 million.

Also on the millennium scale,

we can look at the way of life
of early civilizations,

such as the ones described in the Bible.

And in this supposed source
of our moral values,

one can read descriptions
of what was expected in warfare,

such as the following, from Numbers 31:

"And they warred against the Midianites
as the Lord commanded Moses,

and they slew all the males.

And Moses said unto them,
'Have you saved all the women alive?

Now, therefore, kill every male
among the little ones

and kill every woman that hath known
man by lying with him,

but all the women children that have not
known a man by lying with him,

keep alive for yourselves.'"

In other words: kill the men,
kill the children.

If you see any virgins, then you can keep
them alive so that you can rape them.

And you can find four or five passages
in the Bible of this ilk.

Also in the Bible, one sees that the death
penalty was the accepted punishment

for crimes such as homosexuality,

adultery, blasphemy, idolatry,
talking back to your parents --

(Laughter)

and picking up sticks on the Sabbath.

Well, let's click the zoom lens down
one order of magnitude

and look at the century scale.

Now, although we don't have
statistics for warfare

throughout the Middle Ages
to modern times,

we know just from conventional history

that the evidence
was under our nose all along

that there has been a reduction
in socially sanctioned forms of violence.

For example, any social history
will reveal that mutilation and torture

were routine forms of criminal punishment.

The kind of infraction today
that would give you a fine,

in those days, would result
in your tongue being cut out,

your ears being cut off,
you being blinded,

a hand being chopped off and so on.

There were numerous ingenious forms
of sadistic capital punishment:

burning at the stake, disemboweling,
breaking on the wheel,

being pulled apart by horses and so on.

The death penalty was a sanction
for a long list of nonviolent crimes:

criticizing the king,
stealing a loaf of bread.

Slavery, of course,
was the preferred labor-saving device,

and cruelty was a popular
form of entertainment.

Perhaps the most vivid example
was the practice of cat burning,

in which a cat was hoisted on a stage
and lowered in a sling into a fire,

and the spectators shrieked in laughter
as the cat, howling in pain,

was burned to death.

What about one-on-one murder?

Well, there, there are good statistics,

because many municipalities
recorded the cause of death.

The criminologist Manuel Eisner

scoured all of the historical
records across Europe

for homicide rates in any village,
hamlet, town, county that he could find,

and then he supplemented them
with national data

when nations started keeping statistics.

He plotted on a logarithmic scale,

going from 100 deaths
per 100,000 people per year,

which was approximately the rate
of homicide in the Middle Ages,

and the figure plummets down

to less than one homicide
per 100,000 people per year

in seven or eight European countries.

Then, there is a slight
uptick in the 1960s.

The people who said that rock and roll
would lead to the decline of moral values

actually had a grain of truth to that.

But there was a decline from at least
two orders of magnitude in homicide

from the Middle Ages to the present,

and the elbow occurred
in the early 16th century.

Let's click down now to the decade scale.

According to nongovernmental organizations
that keep such statistics,

since 1945, in Europe and the Americas,

there has been a steep
decline in interstate wars,

in deadly ethnic riots or pogroms

and in military coups,
even in South America.

Worldwide, there's been a steep decline
in deaths in interstate wars.

The yellow bars here show
the number of deaths per war per year

from 1950 to the present.

And, as you can see,
the death rate goes down

from 65,000 deaths
per conflict per year in the 1950s

to less than 2,000 deaths
per conflict per year in this decade,

as horrific as it is.

Even in the year scale,
one can see a decline of violence.

Since the end of the Cold War,
there have been fewer civil wars,

fewer genocides -- indeed, a 90 percent
reduction since post-World War II highs --

and even a reversal of the 1960s uptick
in homicide and violent crime.

This is from the FBI
uniform crime statistics.

You can see that there's a fairly low
rate of violence in the '50s and the '60s,

then it soared upward for several decades

and began a precipitous decline,
starting in the 1990s,

so that it went back to the level
that was last enjoyed in 1960.

President Clinton,
if you're here: thank you.

(Laughter)

So the question is:

Why are so many people so wrong
about something so important?

I think there are a number of reasons.

One of them is we have better reporting.

The Associated Press
is a better chronicler of wars

over the surface of the earth

than 16th-century monks were.

(Laughter)

There's a cognitive illusion.

We cognitive psychologists know

that the easier it is to recall
specific instances of something,

the higher the probability
that you assign to it.

Things that we read about
in the paper with gory footage

burn into memory more than reports
of a lot more people dying

in their beds of old age.

There are dynamics in the opinion
and advocacy markets;

no one ever attracted advocates and donors

by saying, "Things just seem to be
getting better and better."

(Laughter)

There's guilt about our treatment
of native peoples

in modern intellectual life,

and an unwillingness to acknowledge
there could be anything good

about Western culture.

And, of course, our change in standards
can outpace the change in behavior.

One of the reasons violence went down

is that people got sick of the carnage
and cruelty in their time.

That's a process
that seems to be continuing,

but if it outstrips behavior
by the standards of the day,

things always look more barbaric
than they would have been

by historic standards.

So today, we get exercised --
and rightly so --

if a handful of murderers get executed
by lethal injection in Texas

after a 15-year appeal process.

We don't consider
that a couple of hundred years ago,

they may have been burned at the stake
for criticizing the king after a trial

that lasted 10 minutes,

and indeed, that that would have been
repeated over and over again.

Today, we look at capital punishment

as evidence of how low
our behavior can sink,

rather than how high
our standards have risen.

Well, why has violence declined?

No one really knows,
but I have read four explanations,

all of which, I think,
have some grain of plausibility.

The first is: maybe
Thomas Hobbes got it right.

He was the one who said

that life in a state of nature
was "solitary, poor, nasty,

brutish and short."

(Laughter)

Not because, he argued,

humans have some
primordial thirst for blood

or aggressive instinct
or territorial imperative,

but because of the logic of anarchy.

In a state of anarchy,

there's a constant temptation
to invade your neighbors preemptively,

before they invade you.

More recently, Thomas Schelling
gives the analogy

of a homeowner who hears
a rustling in the basement.

Being a good American,
he has a pistol in the nightstand,

pulls out his gun, walks down the stairs.

And what does he see but a burglar
with a gun in his hand?

Now, each one of them is thinking,

"I don't really want to kill
that guy, but he's about to kill me.

Maybe I had better shoot him
before he shoots me,

especially since,
even if he doesn't want to kill me,

he's probably worrying right now
that I might kill him before he kills me."

And so on.

Hunter-gatherer peoples explicitly
go through this train of thought

and will often raid their neighbors
out of fear of being raided first.

Now, one way of dealing
with this problem is by deterrence.

You don't strike first, but you have
a publicly announced policy

that you will retaliate savagely
if you are invaded.

The only thing is that it's liable
to having its bluff called,

and therefore can only work
if it's credible.

To make it credible, you must avenge
all insults and settle all scores,

which leads to the cycles
of bloody vendetta.

Life becomes an episode of "The Sopranos."

Hobbes's solution, "Leviathan,"

was that if authority
for the legitimate use of violence

was vested in a single democratic
agency -- a leviathan --

then such a state can reduce
the temptation of attack,

because any kind of aggression
will be punished,

leaving its profitability zero.

That would remove the temptation
to invade preemptively

out of fear of them attacking you first.

It removes the need
for a hair trigger for retaliation

to make your deterrent threat credible,

and therefore, it would lead
to a state of peace.

Eisner -- the man who plotted
the homicide rates

that you failed to see
in the earlier slide --

argued that the timing
of the decline of homicide in Europe

coincided with the rise
of centralized states.

So that's a bit of a support
for the leviathan theory.

Also supporting it is the fact
that we today see eruptions of violence

in zones of anarchy,
in failed states, collapsed empires,

frontier regions, mafias,
street gangs and so on.

The second explanation
is that in many times and places,

there is a widespread
sentiment that life is cheap.

In earlier times, when suffering and early
death were common in one's own life,

one has fewer compunctions
about inflicting them on others.

And as technology and economic efficiency
make life longer and more pleasant,

one puts a higher value
on life in general.

This was an argument
from the political scientist James Payne.

A third explanation invokes
the concept of a nonzero-sum game,

and was worked out in the book "Nonzero"
by the journalist Robert Wright.

Wright points out that,
in certain circumstances,

cooperation or nonviolence can benefit
both parties in an interaction,

such as gains in trade
when two parties trade their surpluses

and both come out ahead,

or when two parties lay down their arms

and split the so-called peace dividend

that results in them not having
to fight the whole time.

Wright argues that technology
has increased the number

of positive-sum games
that humans tend to be embroiled in,

by allowing the trade of goods,
services and ideas

over longer distances
and among larger groups of people.

The result is that other people
become more valuable alive than dead,

and violence declines for selfish reasons.

As Wright put it,

"Among the many reasons that I think
that we should not bomb the Japanese

is that they built my minivan."

(Laughter)

The fourth explanation is captured
in the title of a book

called "The Expanding Circle,"
by the philosopher Peter Singer,

who argues that evolution bequeathed
humans with a sense of empathy,

an ability to treat other people's
interests as comparable to one's own.

Unfortunately, by default,

we apply it only to a very narrow
circle of friends and family.

People outside that circle
are treated as subhuman

and can be exploited with impunity.

But, over history,
the circle has expanded.

One can see, in historical record,

it expanding from the village,
to the clan, to the tribe, to the nation,

to other races, to both sexes
and, in Singer's own arguments,

something that we should extend
to other sentient species.

So the question is:

If this has happened,
what has powered that expansion?

And there are a number of possibilities,

such as increasing circles of reciprocity

in the sense that Robert
Wright argues for.

The logic of the Golden Rule --

the more you think about
and interact with other people,

the more you realize that it is untenable
to privilege your interests over theirs,

at least not if you want
them to listen to you.

You can't say that my interests
are special compared to yours

any more than you can say

the particular spot that I'm standing on
is a unique part of the universe

because I happen to be standing
on it that very minute.

It may also be powered
by cosmopolitanism, by histories

and journalism and memoirs and realistic
fiction and travel and literacy,

which allows you to project yourself
into the lives of other people

that formerly you may have
treated as subhuman,

and also to realize the accidental
contingency of your own station in life,

the sense that
"There but for fortune go I."

Whatever its causes,

the decline of violence, I think,
has profound implications.

It should force us to ask not just,
"Why is there war?"

but also, "Why is there peace?"

Not just, "What are we doing wrong?"

but also, "What have we been doing right?"

Because we have been doing
something right,

and it sure would be good
to find out what it is.

Thank you very much.

(Applause)

Chris Anderson: I loved that talk.

I think a lot of people
here in the room would say

that that expansion
you were talking about,

that Peter Singer talks about,

is also driven just by technology,
by greater visibility of the other

and the sense that the world
is therefore getting smaller.

I mean, is that also a grain of truth?

Steven Pinker: Very much.

It would fit both in Wright's theory,

that it allows us to enjoy
the benefits of cooperation

over larger and larger circles.

But also, I think it helps us imagine
what it's like to be someone else.

I think when you read
of these horrific tortures

that were common in the Middle Ages,

you think, "How could
they possibly have done it,

how could they not have
empathized with the person

that they're disemboweling?"

But clearly, as far as they're concerned,
this is just an alien being

that does not have feelings
akin to their own.

Anything, I think, that makes it easier

to imagine trading places
with someone else

means that it increases
your moral consideration

to that other person.

CA: I'd love every news media
owner to hear that talk

at some point, it's so important.

CA: Thank you.
SP: My pleasure.