Physics Predicts U.S. Voting Patterns


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ScienceShot: Physics Predicts U.S. Voting Patterns

Building on theories used to describe magnets, scientists have put together a model that captures something very different: voting patterns in U.S. presidential elections. In the model, just two factors directly influence someone’s vote: the proportion of Republicans and Democrats in a voter’s home county and that same proportion in the county where they work. For example, a person who voted Republican in one election and lives in a politically neutral county but works in a heavily Democratic county would likely vote for a Democrat in the next election. Rather than trying to predict the winner in a series of elections, the researchers focused on the distribution of Republican margins of victory across U.S. counties as well as how correlations between two counties’ vote shares changed with the distance separating them, quantities more commonly used to describe the transition from a demagnetized block of iron to a magnetized one. Combining the model of social influence with U.S. census data on commuting patterns, the researchers predicted a bell curve distribution of county-level margins of victory and surprisingly long-range correlations between counties; that suggests that some counties, at least, could feel the effects of social pressures in counties on the other side of the nation, they report this month in Physical Review Letters. What’s more, those patterns were a close match to the actual election data, putting a new spin on some old ideas.

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