Colorado mathematician explains the data behind decision-making for voters

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Posted at 5:54 PM, Jun 14, 2022

BOULDER, Colo. — The first thing people should know about Zack Kilpatrick is that he is not a political scientist. He is a mathematician who relies on equations and data to draw conclusions about how and why people make certain decisions.

But he applies that math to politics to try to determine what is driving voters to make certain decisions.

Kilpatrick is an associate professor of applied mathematics at the University of Colorado in Boulder. Four years ago, he began researching belief spread. What he found was that a rational observer would strongly consider the biases of others before making a decision of their own.

People are not always statistically rational, though, which makes quantifying decision-making difficult.

Social media has complicated the picture significantly, since people are able to filter out others and opinions they don’t like and instead only see the ones that reaffirm their own beliefs. This phenomenon creates echo chambers.

“They basically build their networks of friends based on a principle called homophily, where they will tend to, you know, birds of a feather flock together,” Kilpatrick said. “People now have maybe more choice in who they associate with ideologically than they did in the past.”

Over the decades, Kilpatrick has also noticed in his modeling that political clusters, say Republicans and Democrats, are moving further away from one another ideologically.

Before, while it may have been frowned upon, it wasn’t as controversial when someone voted alongside the opposite party on an issue, big or small. Political clusters also had an easier time of finding common ground.

“People could be much more independently minded as politicians in the past than they can now when there's much more of a herding mentality,” Kilpatrick said.

These days though, political clusters are spread further apart, so traversing the distance to vote with the opposite party is a much bigger feat, leading to more gridlock.

When someone does cross that distance these days, it’s certainly noticed and could be more enlightening.

“If I know that my friend is a lifelong Republican voter and they happen to vote Republican in this election, that doesn't actually give me that much information because they're just sticking with the status quo. But if my friend were to decide to switch to vote Democrat instead, that would give me a lot more information, because it would mean that they had traversed a long distance in their own belief space,” Kilpatrick said.

The example he uses often in his classes is that of U.S. Sen. Mitt Romney voting to impeach former President Donald Trump. It was a decision that was applauded by Democrats but sharply criticized by many on the right. Still, a person choosing to cross party lines can be impactful.

“What we found in our mathematical models is that you can get these waves of decisions where one person's decision to change their mind can then trigger another group of people and another group of people,” Kilpatrick said.

So from a mathematician’s point of view, the best way for people to make rational decisions, whether they are political or not, is to consider their own biases, the biases of the people they are surrounding themselves with, the opinions of people who oppose their ideas, and those in the center before making a decision.