News Release 

Extreme political advertising can hurt campaign efforts

Research identifies top-down and bottom-up formation of political echo chambers

Dartmouth College

Research News


IMAGE: Retweet networks of the 2016 US presidential debates show the rise of echo chambers for Donald Trump (red) and Hillary Clinton (blue) that gradually absorb undecided voters (yellow) across the... view more 

Credit: Courtesy Fu Lab/Dartmouth College

HANOVER, N.H. - December 14, 2020 - Aggressive political messaging can work against candidates by radicalizing supporters and alienating moderates, according to a Dartmouth study.

The research, published in Physical Review X, shows how messages conveyed through political advertising and media appearances can move voters into extreme social networks, making them less influential with undecided voters and others in the middle of the political spectrum.

"The common belief is that political advertising helps a candidate's efforts," said Feng Fu, an assistant professor of mathematics at Dartmouth and the senior researcher on the study. "This research finds that overly-amplified exposure and super-strong positioning of a campaign can actually lessen the likelihood of winning the widespread support that is desired."

In the study, researchers used a computer model to simulate social media users to assess how political campaigns, personal beliefs and social relationships impact interactions between individuals.

When extreme political messaging was introduced, the researchers found that supporters moved toward more extreme opinions.

While political messaging might have the effect of solidifying support of existing backers, aggressive communications had the negative impact of pulling supporters away from voters that occupy more moderate social spaces. Once networking within more extreme groups, those individuals are no longer able to persuade undecided voters to support a desired candidate.

"Political strategists need to consider how attack ads and other extreme messages might backfire," said Xin Wang, who served as lead author of the research paper as a visiting PhD student at Dartmouth, "existing supporters may become too radical for their relatively moderate, undecided friends."

In addition to showing the potential negative effect of top-down political advertising, the research also demonstrates the impact of bottom-up exchanges--such as social media sharing between individuals.

The study shows that when people are relatively open-minded with their politics, they can be pulled into echo chambers through everyday political discussion with people who have somewhat similar political opinions.

"In our model, opposing echo chambers only form when people are willing to have their minds changed," said Antonio Sirianni, a postdoctoral fellow at Dartmouth who co-led the study. "When individuals consider opinions similar to their own, but ignore substantially different opinions, the environment becomes ripe for polarization."

The new study builds on well-known concepts of how echo chambers are formed, including "confirmation bias," where people are more likely to accept claims that are consistent with their pre-existing beliefs, and "selective exposure," where people seek out individuals with similar beliefs.

The Dartmouth study differs from past research by demonstrating the impacts of external political campaigns and influencer messaging on political processes.

As part of the paper, the research team provides a visual example of polarization on Twitter during the 2016 U.S. presidential campaign to describe the research model.


Xin Wang is currently with the School of Mathematical Sciences at Beihang University. Shaoting Tang and Zhiming Zheng, from Beihang University, also participated in the study.

About Dartmouth

Founded in 1769, Dartmouth is a member of the Ivy League and offers the world's premier liberal arts education, combining its deep commitment to outstanding undergraduate and graduate teaching with distinguished research and scholarship in the arts and sciences and its leading professional schools: the Geisel School of Medicine, the Guarini School of Graduate and Advanced Studies

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