Theoretical physicist Stefan Bornholdt is available to discuss his “repulsion”-based voter model for stalemate elections.
November 4, 2020 — Despite pre-election polls, which overwhelmingly pointed to a democratic victory, election results for presidential candidates Joseph Biden and Donald Trump are near 50-50 as ballots continue to be counted. The pattern bears a striking resemblance to numerous historical elections in the past decade — the 2014 Swiss referendum on mass immigration, the 2016 U.S. presidential election, and the British Brexit vote. All three were characterized by controversial issues and hostile attacks on both sides, and all three ended in a near-stalemate, with a narrow margin of defeat or victory for the losing and winning parties.
Theoretical physicist Stefan Bornholdt and his colleagues have a model that explains what drives public opinion toward stalemate. In a word, it is repulsion. By adding repulsive messages to a classic voter model, the team found that stalemate and polarization suddenly emerged when political messages between candidates were highly repulsive. (A real-world example of repulsive messaging would be the combative behavior seen in the first U.S. presidential debate of 2020). As voters (aka “agents”) in the model were either convinced or repelled by candidates’ statements, they could change sides or switch to an undecided state if they came to doubt their former opinion. The model shows that when the messaging between sides is contentious, and a voter is repelled by at least one out of four statements, a phase transition occurs where neither party can win in the long run and no clear winner emerges.
The model uses mathematical tools drawn from physics, which were first used to describe collective phenomena in magnets. It was published in the journal Physical Review E in 2019.
<https://journals.aps.org/pre/abstract/10.1103/PhysRevE.100.042307>
A preprint version of the full text is posted on the arXiv server. <https://arxiv.org/abs/1909.06483>
Stefan Bornholdt is available for media inquiries at <[email protected]>. He is a professor the Institute for Theoretical Physics at the University of Bremen, and is a visiting researcher and collaborator at the Santa Fe Insitute.