BOB GARFIELD: If solidarity and the recognition of mutual self-interest are the keys to moving past our fractious moment, it can be hard to see how we'll get there. Anger and tribalism appear to be at an all-time high, creating political and societal rifts that seem unbridgeable. Indeed, it is hard to believe that only 70 years ago, the country was deemed by political scientists to be not polarized enough. Leading, it was said, to confusion and disengagement on the part of the electorate.

LILLIANA MASON: So in 1950, the American Political Science Association put out a report that suggested that, in fact, the parties were not distinct enough and that it was making people's political decision making too difficult.

BOB GARFIELD: Over the next few decades, they became distinct alright. Lilliana Mason is a political psychologist at the University of Maryland. She says most people know exactly what each party stands for, leaving us with two camps that both seek to destroy the other. To understand that enmity, we need to look no further than the Robber's Cave experiment.

LILLIANA MASON: In 1954, some psychologists collected a bunch of fifth-grade boys from the Oklahoma City area and they divided them into two camps. And they kept the boys completely separate for the first week of camp and the boys came up with their own names for what their camps were called. One was the rattlers and one was the eagles. And in the second week, they let them know that there was another camp down the road. And immediately the boys wanted to have a competition. And the more the boys competed the more they began to hate each other. They call each other nasty names. And then things began to fall apart. They began throwing rocks at one another and at one point it got so violent that the experimenters had to separate them because they were so worried about the boy's safety. So really all that it took was separating them into two different groups allowing them to form an identity and then letting them sort of have at each other. And we all like to think that we're more mature than fifth-grade boys, and hopefully we are, but in general that motive is a very deep-seated psychological motive. Once we are in a group, we think our group is the best and we think that the other groups are less good. And if we're in competition with those groups, we begin to hate them.

BOB GARFIELD: What's interesting to me is that these groups that were placed in opposition to one another was random. When we're speaking of tribalism, what is the role of deliberation and judgment and agency? How much of this is free will and how much of it is just who we happen to be born as?

LILLIANA MASON: That's a very deep question. Part of it comes with the way that we were raised and even partisanship is something that some of the earlier scholars of political behavior said, 'you know, that partisanship is something that's learned at your mother's knee.' If you live in a political household, you grow up learning that you're a partisan. In a similar way that you grew up learning that you are, you know, a Christian if you go to church. And some identities are unavoidable like race. Some identities are things that we choose, but the most important thing to know about identity is that, whether it's something that is given to you or you choose, the most powerful identities are the ones whose status is being threatened. It's the threat to the status not just whether the status is high or low. And it's very easy to make people think about one identity or another simply by telling them that someone has insulted their group or that their group is about to lose in some type of competition. When we see politicians talking about identities or groups, one thing that they have a lot of power in is helping us think about which groups are most important to us by telling us which groups are the most threatened.

BOB GARFIELD: All right, I understand this notion of winning and losing and feeling that your side is under threat, but back, in the supposedly, hypo-partisan 50s, many voters actually toggled between parties based on the economy or wars or other transitory circumstances. What the voting record show about today? Is it about issues or is it just threats to the tribe?

LILLIANA MASON: There was a Pew study. People were asked whether they approved background checks for gun purchases at a federal level. Eighty-six percent of Republicans agreed that this would be a good policy to have in place. And then they were asked whether they believed that the government should pass a bill enacting background checks at a federal level. And once it was phrased that way only, 50 something percent of Republicans agreed that a bill should be passed. These people who believed that the legislation would be good for the country as a whole also believed that it would be bad for their party. And in those scenarios, there are a substantial number of people who will choose the party's victory over what they think is best for the nation as a whole. The fact that our party could switch positions and maintain its voting base almost completely. that's actually a very concerning development because it removes accountability. In the 1950s when people would switch between parties if the party did something that upset them, that was a mechanism by which voters held elected officials accountable. And without that ability, it's a lot harder for voters to hold not only elected officials accountable but also to even pay attention to what their elected officials are doing because the most important thing in their mind is whether or not the party is winning.

BOB GARFIELD: We're talking about winning and losing. We're talking about this political moment where it is all important for the rattlers to defeat the eagles even if they have to resort to violence. Is it any wonder that lunatic partisans are trying to kill perceived enemies? And is there any reason to think that the events of last week were an outlier versus the leading edge of some sort of Sarajevo–Rwanda future where blood is spilled for the team.

LILLIANA MASON: Right. So that is the worst possible scenario. That all of this partisan, dehumanization and social distancing and need for victory becomes something that encourages widespread violence. I think a couple of other things are worrisome in that regard. Right. One is the potential for the loss of the legitimacy of our electoral outcomes. If people don't trust the outcome of elections then the basic machinery of democracy ceases to function. These are kind of the weakest spots of our democracy and they are being tested. We have seen violence and assassinations in American history. The 1960s were not a peaceful time. And so this is not a completely new thing. The difference is that today those types of conflicts that we saw in the 1960s are mapped onto our partisanship. Our elections determine how angry or happy we are with what's happening politically. And so elections can possibly become flashpoints for this type of violence.

BOB GARFIELD: Perhaps especially when the electorate has been groomed to believe that the system is rigged and that there is a deep state trying to delegitimize the elected administration and etc, etc.

LILLIANA MASON: Absolutely. And when one side is particularly encouraging of this, it ends up being an asymmetric effect where the vast majority of Americans don't believe that violence is acceptable at all, particularly in advancing political goals. But some partisans do. And there are enough partisans that accept political violence that it could become dangerous. Now we can look to other countries. This is not my area of specialty. But there are other political scientists who study the emergence of civil war in other countries and there's a political scientist named Joel Selway who does interesting work in this. And he says there are three major predictors of civil war. One is ethnic or religious fractionalization along political lines, which we have. Two is adverse regime change, which would be something like a contested election or an election outcome that many people feel is illegitimate.

BOB GARFIELD: Or an impeachment?

LILLIANA MASON: Right, some sort of regime change that seems illegitimate. But the third is economic catastrophe. That's the one thing that I think is really keeping Americans sort of settled down is that the economy, right now, is relatively healthy and comfortable people don't commit violence in general. In a comfortable society, it really does take a relatively unhinged type of person to commit these types of acts and so, to the extent that it is limited right now to effectively domestic terrorism, we're not in Rwanda.

BOB GARFIELD: No but we may be in Yugoslavia.

LILLIANA MASON: We're, yeah we're hoping that that's not that's not the case. It's a very frightening prospect. And in terms of my research, the best way to get out of it is for there to be some sort of new realignment of the parties. What started this was a massive rift in the Democratic Party after the Civil Rights Act. If there is a massive rift in either party again, particularly the Republican Party, we could see a new set of cues that the parties are giving us and new political information that's giving us some mixed messages or we have crosscutting identities that emerge. And if there were to be a rift in one party, it would reduce polarization because people would have a less clear sense of us and them.

BOB GARFIELD: Liliana, Thank you so much.

LILLIANA MASON: Thank you so much for having me.

BOB GARFIELD: Liliana Mason is a professor of government and politics at the University of Maryland and author of Uncivil Agreement: How Politics Became Our Identity.

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BOB GARFIELD: Coming up Sunshine, pilates and, evidently, evil–the California threat. This is On the Media.

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