Uh oh. No family reunion this spring — but still, Uncle Ron managed to get you on the phone for a chat. It started pleasantly enough, but now the topic has moved to politics.
He says he’s worried that Biden isn’t actually running things as president, and that instead more radical folks are running the show. He points to some video anomalies (“hand floating over mic”) that led to the theory that many apparent videos of Biden are fake.
You point out that the basis for that theory has been debunked — the relevant anomaly was due to a video…
Becca and I grew up in a Midwestern college town. Our friendship was built around small-town life: college football, barbecues by the lake, and so on. If you had asked us about politics, we both would’ve been fairly moderate—and unconcerned—in our replies. It just didn’t matter much, we thought.
Then we went our separate ways. I, to a liberal, urban university; she, to a conservative, rural college. Life got more complicated. Our friendship faded.
And, as you can guess, we polarized.
In the years sense, I’ve become increasingly liberal, and she’s become increasingly conservative. Now, we think, politics really matters.
The most important factor that drove me and my childhood friend Becca apart, politically, is that we went our separate ways, socially. I went to a liberal university in a city; she went to a conservative college in the country. I made mostly-liberal friends and listened to mostly-liberal professors; she made mostly-conservative friends and listened to mostly-conservative ones.
As we did so, our opinions underwent a large-scale version of the group polarization effect: the tendency for group discussions amongst like-minded individuals to lead to opinions that are more homogenous and more extreme in the same direction as their initial inclination.
It’s September 21, 2020. Justice Ruth Bader Ginsburg has just died. Republicans are moving to fill her seat; Democrats are crying foul.
Fox News publishes an op-ed by Ted Cruz arguing that the Senate has a duty to fill her seat before the election. The New York Times publishes an op-ed on Republicans’ hypocrisy and Democrats’ options.
Becca and I each read both. I — along with my liberal friends — conclude that Republicans are hypocritically and dangerous violating precedent. Becca — along with her conservative friends — concludes that Republicans are doing what needs to be done, and that…
So far, I’ve laid the foundations for a story of rational polarization. I’ve argued that we have reason to explain polarization through rational mechanisms; showed that ambiguous evidence is necessary to do so; and described an experiment illustrating this possibility.
Today, I’ll conclude the core theoretical argument. I’ll give an ambiguous-evidence model of our experiment that both (1) explains the predictable polarization it induces, and (2) shows that such polarization can in principle be profound (both sides end up disagreeing massively) and persistent (neither side is changes their opinion when they discover that they disagree).
So far in this series, I’ve (1) argued that we need a rational explanation of polarization, (2) described an experiment showing how in principle we could give one, and (3) suggested that this explanation can be applied to the psychological mechanisms that drive polarization.
Over the next two weeks, I’ll put these normative claims on a firm theoretical foundation. Today I’ll explain why ambiguous evidence is both necessary and sufficient for predictable polarization to be rational. Next week I’ll use this theory to explain our experimental results and show how predictable, profound, persistent polarization can emerge from rational processes.
Polarization is rising in the United States. We all know it. We can sense it. Beyond our own impressions, it’s what the data clearly tells us. Year by year, members of each party agree more amongst themselves, and less with the other side. As a result, they increasingly demonize the other side. From 1994 to 2016, the percentage of Republicans with “very unfavorable” attitudes toward the Democratic Party rose from 21 percent to 58 percent, with a whopping 91 percent having an overall “unfavorable” attitude. The numbers for Democrats are similar.
The core claim of this series is that political polarization is caused by individuals responding rationally to ambiguous evidence.
To begin, we need a possibility proof: a demonstration of how ambiguous evidence can drive apart those who are trying to get to the truth. That’s what I’m going to do today.
I’m going to polarize you, my rational readers.
In my hand I hold a fair coin. I’m going to toss it twice (…done). From those two tosses, I picked one at random; call it the Random Toss. How confident are you that the Random Toss landed heads? …
I haven’t seen Becca in a decade. I don’t know what she thinks about Trump, or Medicare for All, or defunding the police.
But I can guess.
Becca and I grew up in a small Midwestern town. Cows, cornfields, and college football. Both of us were moderate in our politics; she a touch more conservative than I-but it hardly mattered, and we hardly noticed.
After graduation, we went our separate ways. I, to a liberal university in a Midwestern city, and then to graduate school on the East Coast. …
It’s February 2024. Three Republicans are vying for the Presidential nomination, and FiveThirtyEight puts their chances at:
Suppose you trust these estimates. Who do you think will win?
Some natural answers: “Pence”; “Pence or Carlson”; “Pence, Carlson, or Haley”. In a Twitter poll earlier this week, the first two took up a majority (53.4%) of responses:
But wait! If you answered “Pence”, or “Pence or Carlson”, did you commit the conjunction fallacy? This is the…
Philosopher at University of Pittsburgh, working on the question of how irrational we truly are.