A history of violence | Steven Pinker | TEDxNewEngland

Contrary to the popular impression view that we are living in extraordinarily violent times, rates of violence at all scales have been in decline over the course of history. Steven Pinker explores how this decline could have happened despite the existence of a constant human nature.

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Believe it or not,
and I know most people do not,

violence has been in decline
for long stretches of time,

and today we may be living

in the most peaceful era
in our species' existence.

The decline of violence
has not been steady,

it has not brought rates
of violence down to zero,

and it is not guaranteed to continue.

But I hope to persuade you that it is
a persistent historical development,

visible on scales from millennia to years,

from the waging of wars
to the treatment of children and animals.

I'm going walk you through
six major historical declines of violence

and try to offer explanations
for the declines,

in terms of the psychological mechanisms
that impel us toward violence,

the psychological mechanisms
that inhibit us from violence,

what Abraham Lincoln called
"the better angels of our nature,"

and the historical changes
that have favored our better angels.

The first decline of violence
I call the Pacification Process.

Until around 5,000 years ago,
humans everywhere lived in anarchy,

without central government.

What was life like
in this state of nature?

Well, one way of estimating
rates of violence

in non-state versus state societies

comes from forensic archeology.

You can think of this
as "CSI Paleolithic,"

namely what proportion of prehistoric
skeletons have signs of violent trauma,

such as bashed-in skulls,

decapitations,

arrowheads embedded in bones,

or mummies found
with ropes around their necks?

(Laughter)

Here I've assembled 21 estimates -

as you can see they span quite a range,
but they average out to 15%.

Fifteen percent of prehistoric remains
show some signs of violent trauma.

Let's compare that 15% figure
to those of some modern state societies,

such as the United States and Europe
in the 20th century,

with their two World Wars
and many other wars,

that add up to a death rate of 0.6 of 1%.

If we try to get the estimate
as big as possible,

by throwing in all the genocides,

all the man-made famines
across the entire globe,

we can push the rate
to, perhaps, as high as 3%.

And if we look at the world
in the 21st century,

you can not see the bar because it is less
than one pixel high, at 0.03 of 1%.

The second decline of violence
can be appreciated

by examining this woodcut

showing a typical day
in the life of the Middle Ages.

(Laughter)

And the process that brought
this level of mayhem down

has been called the Civilizing Process.

In many parts of Europe,
homicide statistics go back 800 years,

and historical criminologists
have plotted them over time,

such as this graph,

which shows homicides per 100,000 per year

on a logarithmic scale from 1200 to 2000.

And, as you can see,
there's been a massive decline,

so that a contemporary Englishman

has about one thirty-fifth
the chance of being murdered

as his medieval ancestor.

This is true not just in England,

but in every country
for which historical data exist -

here you see Italy, the Netherlands,
Germany, Switzerland, and Scandinavia.

The red line in this graph shows
the average of those five regions.

For the sake of comparison,

I've also put the comparable rate
from non-state societies

in the dot on the upper left.

The gap between the dot
and the beginning of the graph

is what I call the Pacification Process,

the further decline,
the civilizing process.

The third historical decline
of violence can be appreciated

by recalling some of the ways

that law and order was brought
to European territories,

namely sadistic public
physical punishments,

such as breaking on the wheel,
burning at the stake,

clawing with iron hooks,

sawing in half,

and impalement.

But in a development called
the Humanitarian Revolution,

major countries put an end
to the use of torture

as a form of criminal punishment.

This timeline shows from 1625 to 1850

the number of major countries
that had judicial torture,

and, as you can see,
there was a wave of abolitions

in the second half of the 18th century,

including the prohibition
of "cruel and unusual punishment"

in the Eighth Amendment
to the American Constitution,

which took place right
in the middle of this wave.

Also abolished during
the Humanitarian Revolution

was the profligate use
of the death penalty

for nonlethal crimes.

In 18th-century England, there were
222 capital offenses on the books,

including poaching, counterfeiting,
robbing a rabbit warren,

being in the company of Gypsies,

and "strong evidence of malice
in a child 7 to 14 years of age."

By 1861, these had been reduced to four.

Now, the death penalty itself has been
abolished in every Western democracy,

except the United States.

The red line shows the number of European
countries with capital punishment,

from 1775 to the present.

Most of the abolitions
took place in the 20th century,

but the blue line shows
the number of European countries

that actually carry out executions,

showing that before politicians got around

to striking capital punishment
from their countries' law books,

their fellow citizens
had pretty much lost their taste

for executing people.

I mentioned the United States
is an exception

because 33 of the 50 states
still practice capital punishment.

But even in the United States,

capital punishment
is a shadow of its former self,

as you can see from this graph,
which shows the per capita execution rate

from colonial times to the present.

Nowadays about 40 people
are executed every year

in a country that has
more than 16,000 homicides,

and the rate has continued
to go down over the last decade.

Finally, the Humanitarian Revolution
saw the abolition of slavery.

Now, slavery used to be legal
all over the globe.

No one seemed to think
there was anything wrong with it.

The Bible had no problem
with it, for example.

Democratic Athens was
a slaveholding society ...

But starting in the second half
of the 18th century,

there was a trickle of abolitions

which grew into a wave
that swept over the entire world.

As of 1980, when Mauritania
abolished capital punishment,

we're living through a unique era
in human history,

in which slavery is illegal
everywhere on Earth.

The fourth decline of violence
has been called the Long Peace.

And I'm going to skip a number of graphs

because the most relevant statistic

for the Long Peace is zero.

It refers to the historically
unprecedented decline in interstate war.

So here are some examples
of the statistic zero

that symbolizes this era.

There were no wars between
the United States and the Soviet Union,

contrary to every expert prediction that
World War III was just a matter of time.

No nuclear weapon has been exploded
in war since Nagasaki;

again, contrary to all
the predictions from experts

that nuclear war was inevitable.

There've been no wars
between any two great powers

since the end of the Korean war in 1953,

following half a millennium
in which the great powers

were constantly at each other's throats.

There've been no wars
between Western European countries

since the end of World War II.

For the sake of comparison,

prior to 1945,

Western European countries alone
started two new wars a year,

for 600 years.

That number fell, as of 1946, to zero.

And there've been no wars
between developed countries.

The 44 countries
with the highest GDP per capita

have not fought each other since 1946.

And that might even seem
banal and unexceptional

that we think of wars as taking place
in poor backward parts of the world,

but for most of human history,

it was the big rich developed countries
that were constantly waging war,

and because they could afford
big destructive armies,

those wars did the most damage.

Well, what about the rest of the world?

In a process that I call the New Peace,

the long peace is starting to spread
to the rest of the world.

And I'll illustrate it with one graph,
a stacked layer graph,

with the thickness of each layer
corresponds to the rate of death of war

in a particular category
from 1946 to the present.

Here is the rate of death
from colonial wars,

which tapered off to zero as European
empires gave up their colonies.

Here we have the rate
of death from interstate wars,

wars with a country on each side,

which shows a spiky but downward trend,

with bumps corresponding
to the Korean War, the Vietnam War,

and the Iran-Iraq War.

Here we have the rate
of death from civil wars

and internationalized civil wars,

where some country
butts in on a civil war.

The height of the entire stack
represents the worldwide rate of death

from all wars combined.

And, as you can see, the graph shows
a bumpy but unmistakable downward trend.

In the first decade of the 21st century,

you see a thin laminate of layers

showing the unprecedentedly
low rate in deaths of war

from all categories.

Finally we have the Rights Revolutions,

the targeting of violence
on smaller scales

directed against vulnerable
sectors of the population,

such as African Americans,

women, children, and animals.

The Civil Rights Revolution first put
an end to the practice of lynching.

By the end of the 19th century,

about 150 African Americans
were lynched every year -

that's three a week.

By the 1950s, that fell to zero.

The kind of racist attitudes
that licensed attacks on African Americans

have been in steady decline.

This graph shows the percentage of white
Americans that agree with the statement

"black and white students
should go to separate schools,"

and "if a black family moved in
next door, I would move out."

The percentages have fallen
from a majority of white Americans

to the single digits, which is
the range of crank opinion.

The question is no longer even
included in public opinion polls.

The Women's Rights Revolution

has reduced the rate of rape by 80%,
since its peak in the 1970s,

and has brought about a similar decline
in rates of domestic violence.

The Children's Rights Revolution

has reduced the number of American
states with corporal punishment,

that is, strapping
and paddling in schools.

Approval of spanking

and other forms of corporal punishment
of children by their parents

has been in decline
in polls in every Western country.

And rates of child abuse,
both physical and sexual,

have been in decline
since they have been first measured.

The Animal Rights Revolution
has seen a decline in hunting,

a rise in vegetarianism,
both in the UK and in the US,

and a dramatic decline
in the number of motion pictures

in which animals were harmed.

Well, this brings up the question,

"Why has violence declined
on so many scales of time and magnitude?"

I don't believe it's because
human nature itself has changed

and that our violent inclinations
have literally been bred out of us,

but rather that human nature
has always been extraordinarily complex

and it has comprised both inclinations
that tempt us toward violence

and inhibitions that inhibit us.

What are the motives for violence?

I don't believe there is
any one part of the brain

that contains an aggression instinct;

rather, we have distinct motives
such as simple exploitation,

the harming of a person
that happens to be an obstacle

on the path towards
something that you want,

resulting in forms of violence
such as rape, plunder, conquest,

and the elimination of rivals.

There's dominance,

the drive among individuals to climb
the pecking order and become alpha male,

and a corresponding motive among groups

for racial, national,
or religious supremacy.

There's revenge or moralistic violence,

in which you feel
not only is violence permissible,

but it is mandatory in order to punish
those who have wronged you,

resulting in vendettas, rough justice,
and cruel punishments.

And perhaps, most destructive of all
are utopian ideologies,

belief systems from militant religions,

nationalism, Naziism, communism

that hold out the prospect of a world
that will be infinitely good forever.

As captured in the saying, "You can't make
an omelet without breaking eggs,"

namely if you have a belief system
in which the world will be perfect,

well, killing people who stand in the way
is a price worth paying,

which is why, paradoxically,
the worst atrocities in human history

were committed in pursuit
of a moralistic utopian goal.

Well, what do we have on the other side
to counteract these violent inclinations?

What are the better angels of our nature?

There's self-control,
circuitry in the prefrontal cortex

that can anticipate
the consequences of behavior

and inhibit our violent impulses.

There's empathy, the ability
to feel others' pain.

There's the moral sense,
a system of norms and taboos

that govern what we feel
is appropriate behavior.

And finally, there's reason,

cognitive processes that allow us
to engage in objective, detached analysis.

Well, the final question is:

How do we put the history
back together with the psychology?

Which historical developments
bring out of our better angels

and stay our hands before they
can commit acts of bloodshed?

The first possibility
is that Thomas Hobbes got it right

when he extolled "The Leviathan,"

a state and judicial system

with a monopoly on
the legitimate use of force.

A state with a monopoly on violence

can neutralize your incentive
to attack your neighbors

by imposing penalties
that cancel out your anticipated gain.

Just as important, it neutralizes
your neighbors' incentive to attack you,

and so you no longer have to maintain
a belligerent macho stance to deter them,

nor do you have
to pursue vengeance after the fact.

And this can tamp down rates of violence

by circumventing the self-serving biases

that lead everyone in a dispute
to think they're on side of the angels

and that their enemy
is perfidious and aggressive,

and thereby reduce the cycles of vendetta,

in which both sides always think
that there's still a score to settle.

A second mechanism
has been called Gentle Commerce,

the idea that whereas plunder
is a zero-sum game,

the advantage to the aggressor
is canceled out by the loss to the victim.

Trade is a positive-sum game,
one in which everybody wins.

And as improving technology
allows the trade of goods and ideas

over longer distances, among larger
groups of people, and at lower cost,

it becomes cheaper to buy
stuff than to plunder it,

and other people become
more valuable to you alive than dead.

(Laughter)

A third possibility has been called
the Expanding Circle,

and it builds on the biological fact

that evolution has given us all
a sense of empathy.

Unfortunately, by default,

we apply our empathy only
to a narrow circle of blood relatives,

close allies, and cute
little fuzzy animals.

But over the course of history,

the expansion of literacy, travel,
and cosmopolitanism

has led us to enlarge
our circle of empathy,

from just the family
to the village, the clan, the tribe,

the nation, other races,
both sexes, children,

and perhaps eventually to other species.

Finally, there's the Escalator of Reason,

the possibility
that the growth of literacy,

education and public discourse

has encouraged people to think more
abstractly and more universally.

People rise above
their parochial vantage point.

This makes it harder to privilege
your own interests over someone else's

just because I'm me and you're not.

It allows people to stand back

and recognize the futility
of cycles of violence

and increasingly see violence
as a problem to be solved

rather than as a contest to be won.

Finally, what is the common denominator?

Is it a massive coincidence
that these four forces

have all pushed
in a "peaceward" direction?

Or is there some reason
why they have all unfolded in this way?

I think there is a reason,

and that is that violence is what
game theorists call a social dilemma.

It's always tempting
to an aggressor to exploit a victim,

but of course it is ruinous to a victim.

So, since aggressors and victims
change places over the long run -

anyone can be a [victim] or an aggressor -

all parties would really be better off

if everyone could agree
to renounce violence.

The dilemma is,

how do you get the other guy to renounce
violence at the same time as you do?

Because if you beat
your swords into plowshares,

but the other guy keeps his as swords,

you could find yourself
at the wrong end of an invading army.

One can well imagine
that over the course of history,

human experience and human ingenuity

have gradually chipped away
at this problem

just like we've dealt with other scourges
of the human condition,

like pestilence and hunger,

and the common denominator
among these four forces

is that all of them work to increase

the material, emotional,
and cognitive incentives of all parties

to avoid violence simultaneously.

Thank you very much.