What do you believe is the single most important factor driving up the cost of living in Nigeria?

What do immigration, inheritance taxation and cannabis legalization have in common? Not much, actually. Yet if we know somebody's stance on one of these issues, we can make a good guess about their view on the others.

Politics often seems to work in one dimension: parties and politicians are located on a spectrum stretching from from far left to far right. Knowing someone's opinion on a single wedge issue is often enough to place them on this ideological dimension, which in turn makes it possible to predict their positions on other issues. And in countries such as the US we've seen more and more people polarized into opposing political camps at either end of this spectrum.

One-dimensional politics can seem as natural to us as an apple falling from a tree—it's simply how we think about politics. But just like gravity, the mysterious force shaping our politics in this way does warrant a scientific explanation.

My colleagues and I wanted to understand how people end up so profoundly divided, and the study we published earlier this year proposes a model for how it might work. It suggests the less we are able to separate politics from personal relations, the more polarized we become.

This is more than just an academic matter. If politics is reduced to a single ideological dimension, it can keep us from finding innovative solutions to our most urgent problems.

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