Through The Wormhole Episode Scripts

N/A - Can We Eliminate Evil?

Freeman: From the dawn of recorded history to the present day, humankind has struggled with its darker nature.
We know that psychopaths can torture and kill without remorse, but what compels seemingly normal people to commit acts of cruelty and violence? Today, researchers are uncovering the hidden forces that inflame our inner demons, looking for ways to neutralize our deadliest urges and change human nature.
Can we eliminate evil? Space, time, life itself.
The secrets of the cosmos lie through the wormhole.
Few people consider themselves evil, yet evil seems an inescapable part of life.
The mystery is -- why? For millennia, we blamed the devil -- a creature of darkness that made us do terrible things.
Today, most Christians believe Satan is just a symbol.
Psychologists and brain scientists have shown us that the evil we fear comes from within ourselves.
Will it always be there, or can science find its roots and destroy it? When I was about 9 years old, we moved back to Chicago.
Being new in the neighborhood, I became the target of a bully.
One day, I decided enough was enough.
But as I watched him lying there on the ground, I found I just couldn't savor my unexpected victory.
I wondered, what made this kid so mean? Are some people just born bad? [ Cracking ] [ Grunts ] Man: And cut! So, what I need you to do for the next one is really curl out a bit more.
I need to see more pain in there.
Freeman: In Amsterdam, neuroscientist Christian Keysers is looking for the source of human cruelty.
Okay, so I really want to seem as I'm fighting, where Freeman: Christian investigates empathy -- our ability to identify and respond to what someone else thinks or feels.
Okay, that was good.
To find out how empathy works in our brains, Christian makes short films of painful acts to screen for test subjects.
We need very controlled stimuli, where we just see two or three seconds of pain, and we need to repeat many of them, which is why we need to make them ourselves.
So our actors are typically our graduate students and postdocs, because they know what they're doing and they can take some pain.
Freeman: Christian screens his torture films in a theater unlike any on earth.
Magnetic sensors inside this fMRI machine will peer deep into this man's brain, showing which areas are active when he experiences empathy.
Okay, so I'll give you this button box.
What I want you to do is, each time, to rate what you felt in this particular trial.
First, Christian records what happens in the subject's brain when he sees someone else in pain.
[ Cracking ] Then he measures what happens when the subject experiences pain first-hand.
Now he compares the brain scans.
So, the emotional empathy we've been studying here, you would mainly see in parts of your brain that are not on the surface of your brain, but inside of the insula that's a little bit deeper here, and, really, in the midline between your two hemispheres.
Okay, so what you're seeing here is basically in red -- the brain activity that happened while we were hitting the subjects in the scanner.
And then here, you see two of the emotional-brain regions.
They really add this feeling of unpleasantness to what you feel.
So, they're telling you, kind of, "Ouch, I don't like that.
" And so what we're seeing here, in the bottom, the brain activity that happens while the subject was watching somebody else's pain.
All of these more emotional areas get reactivated, as if the subject had been feeling pain himself.
Whenever you see the pain of somebody else, you will share it inside of yourself.
The other person becomes part of yourself.
The pain of others is not just something you see out there.
It basically comes inside of you, and it becomes your pain, as well.
Freeman: After screening hundreds of people, Christian believes that empathy is hard-wired into nearly all of our brains, but it is not distributed equally.
There is a curve of empathy.
Some people are extremely empathetic, others feel almost nothing.
Think of a romantic movie.
Most of us get caught up in the emotions on screen.
But -- but why? This has to be the end.
[ Sobbing ] Freeman: But for a few of us, it plays like this.
[ Ship horn blares ] People with low empathy see and hear things differently because their brains work differently.
Information flows through most brains like boats move along the canals of Amsterdam.
But in some brains, that movement is impeded by narrow, or blocked, channels.
So, if you imagine that back there, you would have the visual-brain areas that see what happens to others, and down there, you would have the emotional areas that normally feel your pain.
And we think that what makes the difference, basically, between a very empathic person and a less empathic person is just the size of the canal that brings the information from the visual part of your brain to the emotional part, in which you will share the pain of other people.
Freeman: And what of the monsters of our nightmares -- the psychopathic killers who look normal on the outside [ Camera shutter clicks ] but are twisted on the inside? It is often said that psychopaths have no empathy, and this lack of empathy makes them evil.
They are able to torture and kill because they can't relate to other people.
Christian disagrees.
Keysers: Well, I think the finding that surprised us most was actually the study on psychopaths.
We went in there with a simple idea that evil people, like psychopaths, would just lack empathy, and what we actually saw in this study is that what makes them evil is more complex.
It's not that they lack the capacity for empathy -- they just don't use it spontaneously.
But if they want to, because, for instance, it serves the purpose of fooling somebody into giving them all their money, then they're quite able to empathize and really get in to people's minds.
[ Gong crashes ] Freeman: So empathy is not everything.
To keep from falling into evil, we also need a moral system to guide our behavior -- a code of conduct that helps us fit in to society and act in a non-destructive way.
Scientists Karen Wynn and Paul Bloom of Yale University believe that moral code may be written into us at birth.
That is a lot of duck you're fitting in your mouth.
I've been studying babies now for just a little over 20 years.
The more that I see of them, the more complex they become.
There is a lot going on in there, and it's far more rich and complex of a mental life than we had ever thought.
Bloom: By studying babies, you get to see humans before they're contaminated by culture, by television, by a lot of social interactions, by sex and romance.
You get to see humans, in some sense, in their purest form, and you could ask, "what's our natures? "Are we kind? Are we cruel? Are we morally intelligent? Can we tell good from evil?" And the work I'm doing here with my colleague suggests that very early on there's some fundamental moral sense -- some moral instinct that's present in all of us.
Freeman: How do you pose moral questions to a baby? Karen devised a kind of morality play for babies to watch and judge.
We show babies a little puppet show in which this one puppet is trying to open a box, and he's trying and he's trying and he just can't quite get it on his own, and another puppet comes along and grabs the other side of the box lid and helps him open it.
They then see the little puppet.
He's trying again to open the box, and a different puppet comes along and jumps on top of the box lid, slams it shut.
Oh! Wynn: And so our question to the babies is, "Babies, do you have any different feelings "towards these two characters -- "towards the one who helped, in a nice fashion, open the box, "and towards this other, who just really, quite rudely, "slams it down and foils this guy's attempts to get in to the box?" Which one do you like? And we find that, very reliably, babies, even as young as five and six months of age, will reach towards and reach for the helpful puppet.
That one! [ Laughing ] Okay, good job! Freeman: Layla has chosen the good puppet.
Between 80% and 95% of babies do.
Paul and Karen believe that this is a sign that babies are drawn towards kindness and away from antisocial behavior.
But if most of us are born good, why do some of us turn out so bad? Bloom: Well, there's all sorts of ways in which our sense of good could get perverted.
If you're brought up in a culture which teaches you to be dismissive of others, which rewards selfishness, which rewards bad behavior, your sense of empathy could be blunted.
So we have this built-in morality, but it's fragile.
Freeman: Once we descend into darkness -- assault, rape, murder -- are we lost, or can the impulses that lead to evil be squelched? This man thinks so.
He believes we can strengthen our brains and crush the evil within.
Deep inside every human being is an animal -- a creature whose only goal is survival.
Most of us can contain the animal within, but we all know people who yield to their baser impulses.
Sometimes their actions have terrible consequences.
We blame these people for their evil acts, but do they really have a choice? After years of probing the human mind, neuroscientist David Eagleman of the Baylor College of Medicine has come to a startling conclusion -- with a little bad luck, we could all become monsters.
Along any axis you measure brains, whether that's empathy or intelligence or aggression, you find a big distribution.
Not all brains are the same.
Freeman: You are your brain, and your brain is a delicate, highly complex apparatus.
Injury or disease can alter its chemical balance and physical integrity, which can alter your personality.
If you were to damage your thumb in an accident, that wouldn't change you as a person, but if you damage an equivalently sized chunk of brain tissue, that can change your risk taking, your decision making, and even, perhaps, whether you become a murderer.
In 1966, Charles Whitman climbed to the top of the tower on the U.
Austin campus, and he indiscriminantly shot 48 people.
The only thing that matched the horror of this event was the unexpected nature of it.
There was nothing in his history that would have predicted this sort of behavior.
He was an engineering student.
He worked as a bank teller.
He lived with his wife and his mother-in-law.
So what could explain this? Well, in his suicide note, he said, "When this is all over, I want an autopsy to be performed.
" And what they found in his brain was a tumor about the size of a walnut, and it was pressing on a region of the brain called the amygdala, which is involved in fear and aggression.
Freeman: The amygdala is the center of emotion -- the source of our primal desires.
It is held in check by the frontal lobes and the temporal lobes -- the centers of self-control.
We all have subconscious demons that we keep in check, but when the frontal or temporal lobes are compromised, startling behaviors can emerge -- behaviors we call evil.
This is what probably happened to Charles Whitman.
He sensed that something was wrong with his brain.
He could no longer control his violent impulses.
And one of the battles that humans have to fight is short-term versus long-term decision making.
We have impulses that we want to gratify, and we have longer-term thinking that try to squelch those impulses.
Let's say that I'm considering throwing this brick through this window -- part of me maybe wants to do it, part of me feels it's an illegal act and I'll get caught and I'll get in trouble.
And it's an arm wrestle between these different things.
Some people are better at this than others.
[ Glass shatters, static ] Freeman: David believes we can strengthen our willpower with a little workout.
Together with neuroscientist Stephen Laconte, he is testing something called "the prefrontal gym.
" There are no treadmills here, just a scanner that lets people see how their brains respond when they flex the mental muscles that govern self-control.
You're going to hear some buzzing.
Today, David and Steven are conducting their first-ever test on a criminal offender, a man whose cocaine addiction led him to steal from his friends and family.
Right now, what this gentleman is doing is he's looking at images of drug-use cues, and we're asking him to either enhance his craving to these cues or suppress them.
[ Beeping ] When the addict sees images of drug use, his own craving for drugs spikes.
The fMRI scanner sees this increased activity in the brain and displays it as a measurement on a bar.
When the craving networks in his brain are revving high, the bar moves to the red, but when he fights his dangerous urges, he can push the bar back toward the blue.
With this bio-feedback, he's able to train his brain to resist his impulses.
He's doing great.
I mean, he's actually Eventually, David and Steven hope to take this technology to prisons to try to help criminals not repeat their mistakes.
The beauty about the prefrontal gym is that people are helping themselves.
If they choose to strengthen their long-term decision making, this is the way they can do that.
It doesn't change anything about the person, it just gives them a better opportunity to make good long-term decisions.
Freeman: But there are some for whom this technique may never work -- psychopaths.
They can pass for normal, but they are capable of terrifying acts of evil.
Soon, a revolution in brain science may give us the tools to spot evil brains before they ever commit a crime.
Psychopaths can inflict physical and psychological harm on others without feeling a shred of remorse.
They are the people most of us consider evil, and there are more of them than you might suspect -- up to 3% of the population.
That's a lot of dangerous minds.
What if one of them was yours? If something was wrong with your brain, how would you know? If Jim Fallon got a look inside your head, he could tell you.
He has spent his career studying the anatomy of the brain, with an emphasis on psychopathic killers.
Fallon: Six years ago, two of my colleagues in psychiatry brought me a whole bunch of these scans.
So we're doing PET scans but also some fMRI's, and about 3/4 of the way through, I notice a very definite pattern.
And it turns out that these were scans of really bad killers -- serial killers, and very violent killers.
Freeman: Jim has identified the unique brain structure of psychopathic murderers.
Here are the areas of the brain -- amygdala, anterior temporal lobe, orbital cortex, medial prefrontal cortex, cingulate, back here to the hippocampus, back down -- see, it makes a big loop.
These are the areas that are turned off in psychopaths.
Freeman: Our brain anatomy radically affects how we see the world.
How a normal person would see the world, it would be like driving around in this car.
A normal person would be watching their speed.
They would be putting themselves in other people's shoes.
How fast would you go? What if you had kids here? And you'd be looking at people, they'd be looking at you, nothing to hide.
The world of the psychopathic mind is just quite different.
It's like driving around in this dark car at night.
Now I'm protected from people seeing who I really am.
As a psychopath, one would look out and you'd see these forms walking around, and they're no longer people.
And so, in this way, you know, the psychopath is able to use the night.
That is, the night of not connecting with empathy and emotion with other people, but seeing them as objects to use and to, if they get in the way, just run them over.
Freeman: Jim estimates that at least 40 genes contribute to anti-social personality disorders and psychopathic brain patterns.
These genes influence whether you're violent, narcissistic, or homicidal.
So, if you have the genetics of a killer and the brain anatomy of a killer, are you destined to become a killer? For Jim Fallon, this question was about to become uncomfortably personal.
Worried about Alzheimer's disease, he decided to run brain scans on his entire family.
All of the tests came back fine -- except for one.
So I was comparing at that time all these brains of killers, and I had these sheets that I was analyzing on my desk, and I thought they had gotten mixed up.
That is, I thought one of our family's patterns was mixed up with the murderers', 'cause it looked just like the murderers' brains.
And, of course, it turned out to be my brain.
Freeman: Jim's brain showed the telltale psychopathic coldness around the amygdala and the orbital cortex.
Fallon: When I first saw this, I actually just kind of laughed.
You know, I took it as like it was funny -- a little bit in denial.
And it was a little confusing, but I thought I took it pretty well.
Freeman: Next, Jim analyzed his genetic profile and family history.
He found that he had inherited dozens of high-risk genes and had ancestors who had been convicted of murder.
Then he asked his family and friends if he showed psychopathic traits.
Fallon: They said, "Well, Jim, we've known all along "you're a psychopath -- you just don't really hurt anybody.
"You play with everybody's head, you manipulate people, you're too competitive, you got to win everything.
" You know, all this stuff.
They said, "but, you know, but you're funny, "and, you know, you don't swing at people, "you don't do any of that, so we just let it go, but everybody knows you're a psychopath.
" Freeman: So which is the real Jim? The esteemed scientist and life of the party, or the dangerous man revealed by the brain scans? Fallon: I kind of thought I really knew myself, and so I became very confident -- that I was interested in the brain, I was studying it, I felt confident in myself.
When this happened, you know, when I was 60, that was a shock, actually, when I finally accepted that I wasn't who I thought I was.
Freeman: Jim discovered an unsettling truth, but he was left with a mystery.
If he has the brain and genes of a killer, why isn't he a killer? But given all the, you know, the genetic risk factors and how my brain is, you know, where it's kind of stuck, as it were, I look like I really dodged a bullet.
And it was because my parents and my aunts and my uncles and my grandparents are the people who really kept me happy, that's for sure.
Talk about nature/nurture -- that's when nature/nurture was really happening, in a very positive way.
Freeman: High-risk genes and unusual brain architecture do not automatically create killers.
Childhood abuse seems to be a critical ingredient.
A loving home helped Jim Fallon become a boisterous overachiever, not a dangerous psychopath.
Not all psychopaths are violent criminals, but what do we do with the ones who are? Do we simply remove them from society and throw away the key? Perhaps not.
Researchers are not pioneering a radical way to eliminate evil -- by literally zapping it out of your brain.
Some religions hold that man is a creature of evil.
We may struggle to follow the righteous path, but ultimately, we will fail.
We are all sinners.
But what if we could make people good? In Zurich, Switzerland, Dr.
Christian Ruff is blazing a trail on a controversial frontier of neuroscience -- changing the way people think and behave.
Huff: Human behavior is quite unique in the animal world.
In contrast to us animals, we don't just follow our self interest, but we're able to actually control our behavior in line with social norms and rules -- pretty much like the rules of this card game that we're playing here.
People are always tempted to break rules, to break laws, and the problem really is that if some people start doing this, if some people start breaking out of social norms, then very soon, chaos ensues.
[ Crowd screaming, siren wails ] So it's quite important for society to put in place strong-punishment threats -- to basically instill in people's heads the knowledge that if they violate certain norms, certain laws, then they will get punished.
Freeman: What do we do with people who cannot or will not follow the rules of the game? Christian's solution is to zap their brains with electricity.
These players are linked together in an interactive video game.
They all wear headbands designed to pass electrical current into the parts of their brains that control altruism, or concern for the well-being of others.
With a targeted electrical pulse, Christian has found that he can make people, including himself, much more considerate.
Ruff: In the beginning, there's a slight tingling underneath the electrodes at the scalp for about 30 seconds or so, but afterwards I can't really feel it anymore, whether I'm being stimulated or not.
Freeman: Today, Christian and the volunteers are going to play a simple profit-sharing game.
Each player is allotted a sum of money and decides how much to give an anonymous partner.
You have to decide on every trial what your opponent -- the other person -- will consider to be fair.
Here in this example, for instance, I can decide now the white is what I keep and the black is what I give to the other person.
So I keep a lot -- 70%.
And, in this condition, the other player can now punish me.
Oh, and that's what they did.
They took everything away from me for being so selfish.
Freeman: At first, most of the players act selfishly, but then the electricity begins to flow.
After five minutes of brain stimulation, Christian and the other players are now much more willing to compromise.
[ Beep ] This is another punishment trial, actually, so I'm going to give a bit more now, actually, to the other person.
And let's see whether they punish me or not.
Oh, no, okay.
So I get to keep what I basically chose for myself.
Freeman: The headbands have coerced the players into being nice.
These behavioral changes are temporary.
They persist for about 20 minutes after the stimulation stops, but Christian believes that repeated treatment will condition people to act kindly.
Could this technology be used in jails and mental hospitals to suppress evil thoughts and turn criminals back into good people? Ruff: I think we're definitely not at the point yet where we can employ these methods to make people who commit very selfish acts that harm others not commit them.
But by understanding these brain processes and how we can affect them with brain stimulation, we might be getting there one day.
It's definitely not too far away.
Freeman: Neuroscientist Jim Fallon agrees.
In fact, he believes we already have the means to do it with drugs.
The big question is, can we control those behaviors that we consider evil in people? And the answer's probably "yes.
" It depends on how far you want to go.
What one could do is just simply snort, intranasally -- up the nose -- different compounds.
And so let's say one has a problem with impulse control.
Well, impulse control happens to be that area -- orbital cortex -- right above where the smell receptors are, so it's the first thing that's hit.
So one could simply put in pieces of DNA that will be snorted in and concentrate at the orbital cortex that will increase those neurotransmitter systems that increase the function of the area and, therefore, inhibition.
We could decide to do it so that everybody has their own cocktail of behavioral modification.
It will only last a certain amount of time.
This is something that society could do.
It sounds a little wild, but it's completely doable.
Freeman: We may soon have the means to reshape damaged brains and stop violent behavior before it starts.
But this neuroscientist thinks eliminating evil will take more than peering into the heads of criminals.
We must also probe the minds of those who judge them.
Today, we tend to punish criminals more for the harm they inflict than for their evil intent.
That's understandable.
It is much easier to count bodies and bullet holes than determine what was going on in someone else's brain.
But what if we could peer into criminal minds and judge them on the evil we find there? That day may be coming soon, when the true motives of not just criminals, but also the people who judge them, are laid bare.
As one of the few people in the world who is both a biologist and a lawyer, Owen Jones has a unique view of criminal justice.
Objection, Your Honor.
This mock courtroom is part of Owen's laboratory, a place where he explores what goes on in the minds of criminals, judges, and juries.
Jones: So, we're seeing a lot of increasing effort to bring neuroscience into the courtroom, for better or for worse.
Sometimes, for example, criminal defendants may be bringing evidence of their own brain scans to try to avoid conviction altogether -- to say "I should not be held responsible.
" Freeman: But Owen's focus is not so much on criminal brains as on the brains of the people who determine their guilt.
And he's finding that the ways we judge evil behavior are severely flawed.
Jones: Our legal system requires jurors to be amateur mind readers.
They're supposed to figure out not just who did it, but what was the mental state of the person who did it? Do you remember the police coming to your house later that night? Yeah.
They woke me up about 3:00 a.
Freeman: Owen has found that jurors are not good at distinguishing the gray areas of criminal intent.
Emotional circumstances will bias their decisions.
Say two men drive home drunk from the bar.
[ Tires squealing ] One hits a tree.
The other hits a tree and the little girl in front of the tree.
The first man will get a light sentence.
The man who killed the girl will go to prison.
The question is, for how long? Owen has found that jurors are likely to give this man the stiffest possible sentence.
Jones: Jurors have a tendency to think that the driver had a higher level of intent -- a knowing level of intent, instead of a reckless level of intent, for example -- than he actually did.
Freeman: In other words, even though the two drivers had exactly the same level of intent, jurors will believe the driver who hit the girl was more evil than the other driver.
When emotions dominate, judgments are harsh.
At other times, jurors will shut off their emotions completely and inexplicably excuse murderous intent.
Jones: Suppose, for example, that I want to poison my friend Amy, causing her death -- and I believe her to be very allergic to poppy seeds.
I sprinkle poppy seeds liberally, and I serve it to her.
Unbeknownst to me, Amy's not allergic to poppy seeds, and so she does not die.
But let's vary the circumstances a little bit.
Suppose that, although she's not allergic to poppy seeds, Amy is very allergic to peanuts, and unbeknownst to me, who wants to kill her, the chef in the kitchen puts peanuts on her salad.
If she dies as a consequence, a lot of people will start to think, "Wait a second, "I shouldn't be punished for attempting to murder her because I didn't actually cause the harm that befell her.
" So in a way, the fact that somebody else caused her death operates as a shield to my liability and punishment.
Freeman: Once again, the criminal has been judged on results, not on his intentions.
Owen suspects there is a neurological explanation for this.
To find out what happens in the brain when we try to gauge levels of evil, Owen has put judges and jurors into brain scanners and presented them with criminal scenarios like these.
He first discovered significant activity in a region called the dorsolateral prefrontal cortex.
It governs analysis and cognition.
This part of the brain seems to be doing a lot of the heavy lifting in deciding whether or not to punish someone at all.
Freeman: But once the prefrontal cortex decides to punish, another part of the brain decides how much -- the amygdala, which governs our emotions.
The punishment decision is a product of two very different regions -- one highly analytic, one more emotional that is setting a punishment amount -- that are separately deployed but yet jointly involved in yielding the punishment decision.
Freeman: Balancing the emotional and analytic parts of the brain is the magic trick required of every judge and jury.
If jurors have reduced function in either area, their punishment decisions could be flawed.
Jones: Research like this may enable us to de-bias decisions really focused on those aspects of a person's behavior that we want to take most into account when setting degrees of culpability.
Freeman: Owen hopes his findings will eventually lead to fairer sentencing -- that we will eventually have a legal system that only imprisons people who truly want to do harm to others rather than those who simply made tragic errors.
But even if we improve the way we judge criminals, it will not be the endgame in the struggle to eliminate evil.
Because, as history bears witness, sometimes entire societies lose their moral compass.
How do we stop the evil that poisons whole nations? We know that evil can twist and bend solitary minds, but there's another form of evil that infects whole societies.
It compels ordinary people to support genocidal regimes and economies based on slavery.
What makes societies turn bad? Can we stop it from happening? Karen Wynn's experiments at Yale show that even babies have a sense of good and evil and seem to prefer goodness.
But Karen runs another experiment that is far less comforting.
It shows that the human tendency to identify with groups and discriminate against those not in "our" group starts very young.
In this study, we present the baby with two food choices -- graham crackers and, say, green beans.
Then, we bring babies into our experimental room, and they're introduced to two puppets.
And each of the puppets gets a choice between graham crackers and green beans.
Mmm! Yum! I like graham crackers! The other puppet shows the opposite preferences.
Ew! Yuck! I don't like graham crackers.
What we find, quite reliably, is that babies tend to choose the puppet who expressed the same tastes as they themselves did.
Which one do you like? That one! Okay, good job! Does he get a hug? [ Laughs ] Freeman: Babies not only prefer puppets that agree with them, they also like to see puppets that don't agree with them get punished.
The puppet who doesn't like graham crackers has become an outsider -- not part of the baby's group.
My heart felt sad when I got that result because it did tell me that this preference for similarity that we're observing in babies under a year of age isn't just a trivial, superficial, fleeting thing, but it is having consequences across their psychological terrain, in terms of how they think about these characters, what they expect of them, their perceptions of them, and also how they want them to be treated in the social world.
Freeman: Karen believes our brains are built to care more about people close to us, in our group, than those further away.
And we segregate ourselves along lines drawn as simply as whether or not you like graham crackers or have the same color skin.
Sometimes this can have very bad consequences.
[ Shouting in German ] [ Crowd cheers ] Freeman: Steve Pinker is an experimental psychologist and cognitive scientist at Harvard.
Pinker: A lot of the worst atrocities in history came about when one group dehumanized or demonized another.
They may have thought that they were subhuman, that they were like vermin, like rats or cockroaches.
A lot of moral progress might come when we change our mind-set, and instead of dividing people into groups, think of the species as a group.
Think of the world as being one big village and everyone is part of our tribe.
Freeman: Steve thinks this change in thinking, from identifying with small groups to belonging to one inclusive society, is slowly happening.
The most obvious effect has been a dramatic decline in violence.
Pinker: When I tell people that violence has been in decline for long stretches of time and that we're probably living in the most peaceful era in the history of our species, they think I'm nuts.
So I had to make the case with a book that was 800 pages long, with graph after graph and statistic after statistic, just to prove the point to people.
For example, not far from where I'm standing, there's an area of Boston that used to be called the "Combat Zone" because there were so many murders and stabbings and muggings.
Now it's being re-colonized by young urban professionals.
Or a few hundred years ago, there were wars going on, not far from here, that involved enemies like Canada and Britain and France.
Now the idea of a war with those countries would seem like a bad joke.
I might have been burned at the stake for beliefs that I hold today, and a hundred years before that, I might have had my head cut off with a hatchet in the Indian wars.
Freeman: It is difficult to overstate just how violent and cruel the world was for much of the history of the human race.
Once, slavery was legal everywhere in the world.
Now it is officially illegal everywhere in the world.
War and murder were daily facts of life.
Now, for most people, they are exceptional events.
Steve attributes most of this change to the increased role of government and the rule of law.
But he also thinks people today are sharper than their ancestors.
Pinker: You might wonder, are people getting nicer because they're getting smarter? And, believe it or not, the answer is, maybe yes.
scores have been increasing throughout the 20th Century and all over the world.
No one knows exactly why, but it's probably a combination of increased schooling and a trickle down of technological and analytic concepts from science into everyday life.
But, as a result, it's not farfetched to think that people could see the benefits of cooperation and see the downsides of violence more as they start to intellectualize their lives.
Freeman: Mass communication and mass transportation are breaking down the barriers between us, and so is our increasing knowledge of how the human mind works.
The more we learn, the more we see the humanity within us all, even those we think of as evil.
A world without a trace of evil will remain a fantasy, but the better we understand the brain, the better able we are to identify the most dangerous among us and stop them before they do serious harm.
We may never eliminate evil, but perhaps we can contain it and reduce the damage it does to our lives.