There are a lot of barriers to changing your mind: ego, overconfidence, inertia — and cost. Politicians who flip-flop get mocked; family and friends who cross tribal borders are shunned. But shouldn’t we be encouraging people to change their minds? And how can we get better at it ourselves?

Listen and subscribe to our podcast at Apple Podcasts, Stitcher, or elsewhere. Below is a transcript of the episode, edited for readability. For more information on the people and ideas in the episode, see the links at the bottom of this post.

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Here’s a riddle: name an activity that you probably don’t enjoy but may still spend 8 or 10 hours a week doing. Something you are compelled to do. By people who probably also don’t like doing this thing. Give up? I’m talking about meetings. When’s the last time you heard someone say, “That was an awesome meeting, a great use of time and full of pertinent information”? I’m guessing the answer is: never. So, for an upcoming episode on the science of meetings, we want to hear from you. Tell us about the worst meeting you ever attended, or maybe the worst meeting you ever ran. Or the best meeting. With lots of details, please. Also: your ideas for making meetings better. Make a brief audio recording — just use whatever voice-memo app is on your phone — and email the file to radio@freakonomics.com, with the subject line “meetings.” Please be sure to tell us your name, what you do, and where you’re from. Thanks.

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Here’s an interesting fact: legislators in several Republican-controlled states are pushing to eliminate the death penalty. Why is that interesting? Because most Republicans have typically been in favor of the death penalty. They’ve said it’s a deterrent against the most horrific crimes and a fitting penalty when such crimes do occur. But a lot of Republicans have come to believe the death penalty does not deter crime — which happens to be an argument we offered evidence for in Freakonomics. They also say the lengthy legal appeals on death-penalty cases are too costly for taxpayers. Some Republicans also cite moral concerns with the death penalty. And so: a lot of them have changed their minds.We’ve all changed our minds at some point, about something. Maybe you were a cat person and became a dog person. Maybe you decided the place you lived, or the person you loved, or the religion you followed — that they weren’t working for you any more. But changing your mind is rarely easy; and it’s not something you set out to do. Although if you’re like most people, you would very much like other people to change their minds. To think more like you. Because as you see it, it’s impossible for the world to progress, to improve, unless some people are willing to change their minds. But like I said, it won’t be easy. Because changing your mind means admitting, on some level, that you used to be wrong. It can be seen as an act of weakness, even heresy.

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Stephen J. DUBNER: Tell me something that you believed to be true for a long time until you found out you were wrong. Robert SAPOLSKY: The list is endless. I used to be a very serious pianist, and I was one of the snot-nosed classical ones who was appalled by nightmares of Ethel Merman and trombones blasting in the background and who knows what else. And then the wonderful person I married turned out to be a musical-theater fanatic. And in fact, my wife is a musical-theater director. DUBNER: So it wasn’t just a case of you accommodating out of love and familial attachment. Your actual preferences changed? SAPOLSKY: Oh, I thrill at the excitement of seeing a bunch of barely-remembering-their-lines high-school students stumbling their way through Music Man or — actually, that’s not true, I still loathe Music Man. But I actually have come to like musicals a whole lot. She and I have done 19 of them now together, she’s directed I’ve been sort of the rehearsal pianist. DUBNER: Oh boy, you really went — you crossed the border then, fully. SAPOLSKY: Yes. Yes.

Who is this guy, and why should we care that he’s changed his mind?

SAPOLSKY: I’m Robert Sapolsky. I’m a professor of neuroscience at Stanford University, and I’m kind of half-neurobiologist, half-primatologist. For about 30 years, I’ve divided my time between your basic rat-lab neurons growing in petri dishes and then studying populations of wild baboons in the Serengeti in East Africa. DUBNER: So considering that I’m not a neuroscientist — in fact, pretty much as far from it as could be — I do have a sense that the brain and the mind may be two separate things, but I’d love you to comment on the relationship between the two. SAPOLSKY: I am completely of the school that mind is entirely the manifestation of brain. So when there’s a change in mind, there’s got to be a neurobiological underpinning.

Sapolsky, as he noted earlier, has changed his own mind quite a lot. He started early.

SAPOLSKY: I was raised as an Orthodox Jew in a major neighborhood specializing in that, in Brooklyn. And somewhere when I was about 14, something changed. And that change probably involved updating every molecule in my body, in that I sort of realized: this is nonsense, there’s no God, there’s no free will, there is no purpose. And I have not been capable of a shred of religiosity or spirituality ever since. DUBNER: And was there a familial schism then? SAPOLSKY: Oh, I was one of those terribly nerdy, scholarly, passive- aggressive kids where I never said a word about it to my highly religious and demanding father. And he went to his grave having no idea. DUBNER: No kidding. How old were you when he died? SAPOLSKY: In my thirties. DUBNER: So had you come home and gone to Yom Kippur with him and faked it, or how did that work? SAPOLSKY: Yeah. Yeah. And not just for the High Holy Days. I’m home for three days visiting and he’s not going to change, he doesn’t need this sort of headache or heartache at this point, so whatever. It just would have been very hurtful to someone of enormous importance to me.

One thing Sapolsky noticed about mind-changing is that it’s easier when you’re younger.

SAPOLSKY: Just noticing the general phenomenon that we get less open to novelty as we get older.

So he worked up a survey to look at people’s preferences in food, music, and so on.

SAPOLSKY: What you wind up seeing is basically if you are not listening to a certain style of music by the time you’re 28 or so, 95 percent chance you’re never going to. By age 35, if you’re not eating sushi, 95 percent chance you never will. In other words, these windows of openness to novelty close. But then as a biologist, the thing that floored me is, you take a lab rat and you look at when in its life it’s willing to try a novel type of food — and it’s the exact same curve! The equivalent of 10-year-old lab rats hate broccoli as much as 10-year-old humans do. And late adolescence, early adulthood, there’s this sudden craving for novelty. And that’s when primates pick up and leave their home troops and transfer into new ones. And then by the time you’re a middle-aged adult rat, you’re never going to try anything new for the rest of your life. It’s the exact same curve, which fascinated me. DUBNER: Did it make you say, “My goodness, I’m biologically programmed to never want to try any new music, food, experience again, and therefore I’m going to push through that.” Or did you accept your fate? SAPOLSKY: It had no impact on me whatsoever. I’m one of those scientist-professor types who’s capable of lecturing on a subject and paying no attention to what I’m saying. Like I’ve spent my whole life studying about the adverse effects of stress on your health and your psyche. And I’m the most frazzled, stressed person around. I’ve gleaned absolutely nothing useful from any of my life work.

There are a lot of reasons why it may be easier to change your mind when you’re younger. It could be the fact that your brain is simply more plastic then — something scientists assumed for a long time but now are starting to question. Or it could be that your positions are less entrenched, so it’s less costly to change them. Or it could be that the stakes are lower: the fate of the world doesn’t hinge on whether you are pro-broccoli or anti-broccoli. But as life goes on:

VOICEOVER: Now there’s nothing wrong with a little indecision.

As the stakes rise.

VOICEOVER: As long as your job doesn’t involve any responsibility.

Changing your mind can get more costly.

VOICEOVER: John Kerry has changed his mind on all these important issues.

When Massachusetts Senator John Kerry ran for President against the incumbent, George W. Bush, in 2004, Kerry’s campaign began to crater after it was shown that he’d changed his position — or at least his votes in the Senate — on a number of issues.

VOICEOVER: If you thought you could trust him, you might want to change your mind too. Francis FUKUYAMA: So I think that’s the way politics itself works.

That’s Francis Fukuyama. He’s a political scientist at Stanford.

FUKUYAMA: My work really centers on research and practice about political institutions.

In 1992, Fukuyama wrote a book that became a sensation. It was called The End of History and the Last Man.

FUKUYAMA: In the late 1980s, as I was following events in the Soviet Union, I said well, to the extent that there is an end of history, it’s going to look like liberal democracy tied to a market economy.

In other words: democracy had essentially won. Not just the Cold War, but the future. And yet: a lot of the recent political momentum is going in the other direction: toward populism and authoritarianism, with a backlash against globalism.

DUBNER: So to what degree do you think your argument was wrong, or at least premature? How confident are you that what we’re seeing now is just a backlash and not actually a reversal or an entirely new strain? FUKUYAMA: I am still reasonably confident. You know, the way I have formulated my hypothesis right from the beginning was that you needed to show not just that there was unhappiness with liberal democracy, but you needed to posit some other form of social organization that was superior, or that was somehow going to displace liberal democracy in the way that communism asserted that it would displace liberal democracy ultimately. And if you look around the world right now, there are competing systems that are not liberal or democratic. So the Chinese have one, Saudi Arabia and Iran have their versions of it. But I actually don’t think that any of those alternative models are likely to become universal in the way that liberal democracy has become, in a fairly impressive way, the default form of government for very many countries around the world.

So Fukuyama has not changed his mind about his most famous assertion — although he is open to it.

FUKUYAMA: If in 30 years, China’s bigger than the United States, richer, continues to be stable, continues to be growing faster, then I have to say well, maybe that is the alternative model.

But he did change his mind on something else. It goes back to that Bush-Kerry era, and the Iraq War.

VOICEOVER: In which direction would John Kerry lead? Kerry voted for the Iraq war, opposed it, supported it, and now opposes it again.

At the time, Fukuyama was well-established as a prominent political thinker. In addition to writing a landmark book, he’s done two stints in the State Department. So his views on the Iraq War were taken seriously.

FUKUYAMA: I signed onto a letter a couple of years before the war saying that the United States ought to take military action.

He wasn’t opposed to the U.S. desire to intervene and topple a dictator — in this case, Saddam Hussein.

FUKUYAMA: That’s happened in the past and it’s had good effects.

But as the invasion drew near, Fukuyama did have a concern.

FUKUYAMA: My main concern was whether the United States was ready to actually stay in Iraq and convert it into a stable, decent country. And the United States has not had a really great record in doing this, in Central America and Vietnam and so forth. And in the months prior to the war, I began to get increasingly worried that we weren’t prepared to actually stick it out. But even I was astonished at how bad the planning had been, and how faulty the assumptions were, that we were going to be greeted as liberators and that there would be a rapid transition just like in Eastern Europe to something that looked like democracy. In retrospect, I wish I had taken a much clearer stand against it before the war actually happened.

The U.S. invaded Iraq in March of 2003.

FUKUYAMA: I was at a dinner at the American Enterprise Institute in February of 2004.

The A.E.I. is a conservative think tank in D.C.

FUKUYAMA: Dick Cheney was the featured speaker and everybody in the room was cheering like this was the biggest success for American foreign policy, that they could imagine. And I just looked around at the people at my table and I said, “Why are these people clapping?” Because clearly this thing is turning into a huge fiasco. And that’s the moment that I decided these people are really nuts. I mean, they’re so invested in seeing this as a success that they can’t see this reality that’s just growing right in front of their eyes. And to this day — I mean it does seem strange to me that a lot of the people that were strong supporters of the war, even today, are not willing to admit that that was a mistake. DUBNER: The investment that you’re describing, how would you characterize it? Was it more personal, do you think, or more political? Was the thinking more emotional or logical, and using logic to find facts that supported the underlying argument? FUKUYAMA: Well, it’s both. I mean, there has been a lot of research in social psychology lately. Like, this model where people just take facts and draw conclusions from them and then base their opinions on that is completely wrong. I mean that’s just not the way people think. They start out with an emotional commitment to a certain idea, and then they use their formidable cognitive powers to organize facts to support what they want to believe anyhow. So the partisan affiliation comes first and then the reasoning process by which you justify it comes second. And unfortunately, affects all of us. We tend to see the world and cherry-pick facts that support our version of the world, and it takes a really big external shock that just clearly proves you wrong. DUBNER: So I understand that even though you were seen as having defected from or abandoned the neoconservative movement, primarily over the Iraq war, that you were not met so warmly by the left, where you moved to. You said in 2006, “I’ve gotten many e-mails that said in effect, well you’re trying to apologize but you’ve got blood on your hands. We don’t accept your apology.” FUKUYAMA: Yeah, it’s interesting, you’re seeing a similar process with a lot of other neocons right now. The neocons as a group have been the core of the never-Trump conservative movement, all of whom had been big supporters of the Iraq war and of George W. Bush, have really turned against Trump in a big way. And there are a lot of people that are not willing to accept them, they say, “It’s too late.” Exactly those words, “You have blood on your hands.” And I think that that is an unduly rigid position. Because in that case, no one should ever change their mind. They should never be hit on the head with reality and then realize that they’ve got a different position that they should take.

When we talk about changing your mind, we need to acknowledge that every situation is, of course, different. Let’s say someone in your family holds a position that you find odious. Why do you find it odious? Maybe you think they’re ignoring the facts. But can’t people hold different positions based on the same facts? Maybe you feel their position lacks moral reasoning. But who said morality is one-size fits all? Or maybe — just maybe — they hold the opposite position simply because it is the opposite.

Julia SHVETS: Suppose a person has some idea about something which doesn’t correspond to reality. It may be that they derive pleasure from having this idea in itself.

That’s Julia Shvets. She’s an economist at Christ’s College, Cambridge.

SHVETS: I study people’s decisions empirically in order to understand better what drives people.

And in the case of someone deriving pleasure from an idea that you disagree with:

SHVETS: In that case, you have to ask yourself whether it’s actually to their benefit for them to be changing their mind.

This idea, that we can be so invested in our beliefs even if we suspect they are wrong — Shvets has found evidence of this in her research.

SHVETS: The incorrect vision of the world may actually deliver some benefits to them.

And she’s found this effect not just in models or lab studies but out in the real world, where people are constantly making decisions about their work, their families, their lives.

SHVETS: It seems to be a very important question whether the beliefs we hold about the outside world are somehow connected to these beliefs about ourselves. When there is a link between these beliefs, it’s not so clear that we should be changing our minds, and what are the costs and benefits of this.

Consider, for instance, an expert who has dedicated their career to a certain policy or line of thinking. What happens in the face of new information? Do you seriously reconsider your long-held position, and go against the tide you’ve been swimming in?

FUKUYAMA: A lot of times you just feel uncomfortable if you say things that disrupt a consensus. And you just don’t want to do it.

Francis Fukuyama is recalling his change of mind on the Iraq war.

FUKUYAMA: A lot of my friends were very, very heavily on the other side. And I lost a lot of them, I haven’t spoken to several of these friends since then. SHVETS: There are two separate questions, whether the person should change their mind and what the effects are for him, and then what the effects are of this for other people.

There’s another factor that Julia Shvets sees as contributing to our reluctance to change our mind: confidence. Or, more accurately, overconfidence — our own belief that we are right, even in the absence of evidence. Just how much unearned confidence is floating around out there? Consider a recent study by Shvets and some colleagues that surveyed over 200 managers at a British restaurant chain. They averaged more than two years on the job and their compensation was strongly tied to a performance bonus. I mention the bonus because it’s related to the survey that Shvets administered.The managers were asked to recall their past performance and to predict their future performance. Presumably, they should have had a pretty good grasp of their standing.

SHVETS: What we found is that only about 35 percent of managers were accurate about the quintile of the performance distribution they were falling into.

In other words:barely a third of them were able to correctly say whether they fell in the top 20 percent of all managers, or the bottom 20 percent, or another 20-percent block somewhere in the middle.

SHVETS: And 47 percent of managers were overconfident about it.

And these were people who had detailed feedback about their performance every quarter. Which is a lot more than most employees get.

SHVETS: So the next question we asked is: how is it possible that people remain so overconfident when they have so much information?

This is where memory comes into play, or maybe you’d call it optimism — or delusion.

SHVETS: People who did worse in the previous competition tended to remember slightly better outcomes. People seem to be exaggerating their own past performance in their head when this performance is bad. So what we conclude from this is that people use memory selectively. They remember good outcomes and they tend to forget bad ones.

So maybe it’s not so much that people refuse to change their minds — or refuse to “update their priors,” as economists like to say. Maybe they just have self-enhancing selective memories.

SHVETS: The data we observe are consistent with them making a choice to suppress some past information.

But there’s also the possibility that people who’ve been at something for a while, who may consider themselves expert, simply don’t believe that non-experts have information worth paying attention to.

FUKUYAMA: So I was in the State Department, in the policy planning staff, in 1989.

Francis Fukuyama again.

FUKUYAMA: And in May of 1989, after there had been this turmoil in Hungary and Poland, I drafted a memo to my boss, Dennis Ross, who was the director of the office that sent it on to Jim Baker, who was the Secretary of State, saying we ought to start thinking about German unification, because it didn’t make sense to me that you could have all this turmoil right around East Germany and East Germany not being affected. The German experts in the State Department went ballistic at this. You know, they said, “This is never going to happen. And this was said at the end of October. The Berlin wall fell on November 11th. And so I think that the people that were the closest to this situation — so I was not a German expert at all but it just seemed to me logical. But I think it’s true that if you are an expert, you really do have a big investment in seeing the world in a certain way, whereas if you’re an amateur like me you can say whatever you think.

As you can see, there are a lot of reasons why a given person might be reluctant to change their mind about a given thing. Ego, selective memory, overconfidence, the cost of losing family or friends. But let’s say you remain committed to changing minds — your own or someone else’s. How do you get that done? The secret may lie not in a grand theoretical framework, but in small, mundane objects:

SLOMAN: Toilets and zippers and ballpoint pens.

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Think of something you have a really strong opinion about. Maybe the best ways to address climate change. The perils of income inequality. How to balance privacy and security. Now think about why you have such a strong opinion. How well do you think could you explain your position?

Steven SLOMAN: If you’re forced to give an explanation, you have to really understand, and you have to confront the fact that you might not understand. Whereas when you give reasons, then you do what people do around the Thanksgiving dinner table. They talk about their feelings about it, what they like, what they don’t like.

That’s Steven Sloman.

SLOMAN: I’m a professor of cognitive, linguistic, and psychological sciences at Brown University. DUBNER: And that means, in a nutshell, that you try to understand what? SLOMAN: I try to understand how people think. DUBNER: Easy question first: How do you get someone to change their mind? SLOMAN: Well, first of all, there’s no silver bullet. It’s really hard. But if you’re going to try, the first thing you should do is try to get them to change their own minds. And you do that by simply asking them to assume your perspective and explain why you might be right. If you can get people to step outside themselves and think about the issue — not even necessarily from your perspective, but from an objective perspective, from one that is detached from their own interests — people learn a lot. So, given how hard it is for people to assume other people’s perspectives, you can see why I started my answer by saying it’s very hard.

One experiment Sloman has done is asking people to explain — not reason, as he pointed out, but to actually explain, at the nuts-and-bolts level — how something works.

SLOMAN: People don’t really like to engage in the kind of mechanistic analysis required for a causal explanation.

That’s true not only for big, thorny issues like climate change or income inequality, but even for things like:

SLOMAN: Toilets and zippers and ballpoint pens.

Unless you are a plumber or you make zippers or ballpoint pens, you probably can’t explain these very well. Even though, before you were asked the question, you would have thought you could. This gap, between what you know and what you think you know is called, naturally, the “illusion of explanatory depth.”

SLOMAN: So, the illusion of explanatory depth was first demonstrated by a couple of psychologists named Rozenblit and Keil. And they asked people how well they understood how these things worked, and people gave a number between 1 and 7. And then they said, “Okay, how does it work? Explain in as much detail as you can how it works.” And people struggled and struggled and realized they couldn’t. And so when they were again asked how well they understood, their judgments tended to be lower. In other words, people themselves admitted that they had been living in this illusion, that they understood how these things worked, when, in fact, they don’t.

Where does this illusion come from?

SLOMAN: We think the source of the illusion is that people fail to distinguish what they know from what others know. We’re constantly depending on other people, and the actual processing that goes on is distributed among people in our community.

In other words, someone knows how a toilet works: the plumber. And you know the plumber; or, even if you don’t know the plumber, you know how to find a plumber.

SLOMAN: It’s as if the sense of understanding is contagious. When other people understand, you feel like you understand.

You can see how the illusion of explanatory depth could be helpful in some scenarios — you don’t need to know everything for yourself, as long as you know someone who knows someone who knows something. But you could also imagine scenarios in which the illusion could be problematic.

SLOMAN: So we’ve shown that that’s also true in the political domain.

Sloman and his collaborator Philip Fernbach basically repeated the Rozenblit and Keil experiment, but instead of toilets and zippers, they asked people about climate change and gun control.

SLOMAN: We gave people political policies. We said, “How well do you understand them?” and “Please explain them.”

Unsurprisingly, most people were not able to explain climate-change policies in much detail. But here’s what’s interesting. The level of confidence in their understanding of issues, which participants were asked to report at the start of the experiment, was drastically reduced after they tried, and failed, to demonstrate their understanding.

SLOMAN: In other words, asking people to explain depolarized the group.

Now, was this a case of simply slowing down and thinking the issue through? Could it be that we’re often inflexible in our thinking simply because we come to conclusions too quickly? Apparently not.

SLOMAN: If instead of saying, “Explain how the policy works,” if what we said to them was, “Give us all the reasons you have for your view on this policy,” then we didn’t get that effect at all. That didn’t reduce people’s sense of understanding; it didn’t reduce their hubris. DUBNER: The ability to change your mind — would you say that’s really important as a human? SLOMAN: I see the mind as something that’s shared with other people. I think the mind is actually something that exists within a community and not within a skull. And so, when you’re changing your mind you’re doing one of two things: you’re either dissociating yourself from your community — and that’s really hard and not necessarily good for you — or you have to change the mind of the entire community. And is that important? Well, the closer we are to truth, the more likely we are to succeed as individuals, as a species. But it’s hard. DUBNER: Do you think that most of us hold the beliefs that we do because the people around us hold those beliefs, or do you think we’re more likely to assemble people around us based on the beliefs that they and we hold? SLOMAN: The former is more often true. That is, we believe what we do because the people around us believe what they do. This is the way humanity evolved. We depend on other people. And it’s not simply a matter of getting us to think more independently. I actually think that this is one of the major problems with the kinds of solutions people are talking about today for our current political problems. I don’t think the solution is give people the information they need. Matthew JACKSON: More information can be good if it’s very well-filtered and curated, but that’s not easy to do in an unbiased way.

That’s Matthew Jackson, an economist at Stanford. (Yes, I realize this episode is leaning heavily on Stanford professors.) Anyway, Matthew Jackson studies social and economic networks.

JACKSON: So, in particular, how the structure of social interactions affects people’s behaviors. Anything from how our opinions form to whether we decide to vote for a certain candidate.

Here’s something Jackson has changed his mind about:

JACKSON: One thing I used to think was that people, if you gave them the same kinds of information, they would make decisions the same way. They might have different experiences in their past, different influences. But somehow the fundamental ways in which they think about things and process things is the same.

That, however, is not what the data say.

JACKSON: The more you look at data, and in particular, the more you look at experiments where people are faced with facts or information, you realize that some people are very single-minded.

In one experiment, Jackson also asked people about climate change. He had everyone read the same batch of abstracts from scientific articles.

JACKSON: We asked people their opinions before they went in to the study, and you could see that people looking at exactly the same article would interpret it very differently depending on what their initial position was.

So again, information isn’t necessarily the solution. In fact, information can be weaponized.

JACKSON: There was a group of about a quarter to a third of the subjects who actually became more polarized, who interpreted the information heavily in the direction of their priors, and actually ended up with more extreme positions after the experiment than before.

We’ve talked about this phenomenon before on the show — that well-educated people who consume a lot of information tend to hold disproportionately extreme views, apparently because they’re really good at seeking out information that confirms their priors. And ignoring information that might run counter.

JACKSON: One aspect of people seeing exactly the same information and coming away with different conclusions is how we interpret and store information in our brains. It’s very easy to sort of snippet things into small little pieces that we can remember. “Oh, this was for or against.” SLOMAN: We don’t like breaking things down in detail. We just — most of us like to have a superficial understanding.

Steven Sloman again.

SLOMAN: Why do you think Obamacare is good or bad, whatever you think about it? Now, the fact is, most people have very little to say about that. Most people just have a couple of slogans. They have the Republican slogan, they have the Democratic slogan; but they don’t actually know about Obamacare, because after all, it’s a 20,000-page document. SLOMAN: I like to say even Obama doesn’t understand Obamacare.

But even if Obama does understand Obamacare, there’s the question of whether his understanding is unduly circumscribed by the people around him.

JACKSON: People tend to associate with other people who are very similar to themselves. So we end up talking to people most of the time who have very similar past experiences and similar views of the world, and we tend to underestimate that. People don’t realize how isolated their world is. You know, people wake up after an election and are quite surprised that anybody could have elected a candidate that has a different view than them.

So one antidote to inflexible thinking is simply balance.

JACKSON: In worlds where our network is well-balanced and we’re actually eventually incorporating everybody’s viewpoint, the system works extremely well.

Unfortunately, a great many of us are quite bad at creating diverse, well-balanced networks. And there’s a reason for this — a reason we struggle to listen to opposing voices and, therefore, have a hard time changing our minds.

SAPOLSKY: We are basically hardwired to divide the world into us and thems. And to not like the thems a whole lot.

That, again, is the half-neurobiologist, half-primatologist Robert Sapolsky, who’s changed his own mind many times.

SAPOLSKY: The domain that I’m most interested in these days is that change thing of turning thems into us-es — and how do we do that? And what the studies tend to show is: take somebody else’s perspective; try to go through what somebody else’s rationalizations are; individuate somebody, break them out of being an automatic them. And think about do they like the same pets that you do? Do they love their kids? Look at a picture of them singing lullabies to their children. Look at a picture of them enjoying the same food that you do. Contact — and this has been floating around for decades as a theory — give people, thems, enough contact with each other and they turn into us-es and it turns out contact works under very specialized circumstances. You’ve got to spend a bunch of time with thems. And us-es and thems need to be in equal numbers and in a neutral setting and you’ve got to have a shared sort of goal. I mean, all of these work to at least some degree. The peoples we hated in the past are allies now. There are outgroups that spent centuries being persecuted where we don’t even know what the word refers to anymore. And in all those cases, there’s something resembling biological pathways that help thems stop being so objectionable. DUBNER: So before this conversation, if you had asked me what are the primary barriers that keep someone in a given situation from changing their mind, I would have certainly opted for the social and economic explanations. But it sounds as though you’re saying a larger share would go to the physiological and biological reasons, is that right? SAPOLSKY: Well, the really irritating thing I would say is that the two are one and the same. We are nothing more or less than the sum of our biology. Every time you learn something, from something profound to something idiotic, something changes in your brain. Every time you have a sensory experience, your brain is constantly rewiring in major ways.

This idea — that the brain continues to change, physiologically, throughout our lives — this is yet another idea that Sapolsky himself had to change his mind about.

SAPOLSKY: Yeah, this is an aspect my field where I have missed the boat every step of the way. When I started off, this dogma had been in place for like 1,000 years’ worth of intro to neuroscience classes, which is: the adult brain doesn’t make new neurons. This is the basic premise of all the miserable, untreatable neurological diseases out there. And starting in the 60s, there was a one lone prophet named Joe Altman whose career was basically ruined because he was about 30 years ahead of the curve. And then in the late 80s, early 90s, some technique got a lot more sensitive and was able to show adult neurogenesis in the brain like crazy. And it became the hottest subject in the field. And I kept saying, “Ah, nah, that’s not a real phenomenon.” So I was — like really blew it on that one. It turns out that there’s a little pocket, a little population of stem cells, sitting in the hippocampus making new neurons. And what was even better was it made them at all the logical times — in response to learning, stimulation, exercise. And a ton of work showed that these new neurons actually are useful, and they are critical for new types of learning. So that ushered in this whole new world and then this beautiful new edifice of revisionism came potentially crashing down about a year ago. An extremely important and well-done paper that wound up in the journal Nature showed that despite the clear presence of tons of neurogenesis in rodent brains throughout the lifetime, in monkey brains, there was a lot of reason to think that not a lot of the same occurred in the human brain. And that a lot of the prior evidence for it was pretty circumstantial. And as you might expect, the specialists in the field have been stabbing each other over this one ever since. And it’s not clear what the resolution is.

It doesn’t get much more meta than that: a bunch of scientists changing their minds, and trying to change others’ minds, about whether the brain changes when we change our minds. Robert Sapolsky’s own research, about us-es and thems, led to one more change of mind, for Sapolsky.

SAPOLSKY: I would say the biggest thing that came out of that is I am in every fiber of my soul a profound pessimist, and sitting and obsessing for three, four years on what we know about the biological roots of humans being rotten to each other and humans being kind to each other, there’s actually a fair amount of room for optimism. DUBNER: So your belief was that humans are disproportionately cruel to each other. That was the old belief, and the new belief is that that is not necessarily the case? SAPOLSKY: It’s — well, we’re pretty lousy to each other. But the basic paradox of humans is simultaneously we are the most miserably violent species on this planet, and we are the most cooperative. We do stuff which from the standards of evolution and cooperation, game theory, all of that, would make stickleback fish just flabbergasted at how cooperative, how altruistic we are, how often we can do that for strangers. Each one of us, depending on the context can be awful, can be wonderful, or ambiguously somewhere in between.

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Freakonomics Radio is produced by Stitcher and Dubner Productions. This episode was produced by Matt Hickey. Our staff also includes Alison Craiglow, Greg Rippin, Harry Huggins, Zack Lapinski, and Corinne Wallace. Our theme song is “Mr. Fortune,” by the Hitchhikers; all the other music was composed by Luis Guerra.You can subscribe to Freakonomics Radio on Apple Podcasts, Stitcher, or wherever you get your podcasts.