By: Flavia Roscini

Flavia Roscini is a MAIA candidate at the Pardee School of Global Studies at Boston University, specializing in International Communication. Her research interests include international and intercultural communication, climate security, environmental policy, US, UK, and EU affairs.


Americans are more polarized than ever (fig. 1). The Pew Research Center illustrates the increasingly stark divide between partisans on important topics such as “the economy, racial justice, climate change, law enforcement, international engagement and a long list of other issues.”[1] Partisans believe that their differences are not only about politics but also about “core American values.”[2] In his book, Why We’re Polarized, Klein argues that the divisions between the two parties have grown over time, as people’s social identities have slowly become intertwined with their political identities.[3] In a seminal paper on political division, Carothers and O’Donohue confirm that a “powerful alignment of ideology, race, and religion renders America’s divisions unusually encompassing and profound. It is hard to find another example of polarization in the world that fuses all three major types of identity divisions in a similar way.”[4] An essential driver of this polarization is the changing media landscape in the U.S., particularly that of cable news and social media. Traditional and social media channels have exacerbated political polarization by spreading disinformation to their viewers, posing a threat to American democracy.


Figure 1. Pew Research Center

Traditional Media

Media polarization has increased in the past half-decade (fig. 2), and both liberal and conservative partisan media are likely contributing to polarization in the U.S. Cable news networks – of which Fox News and MSNBC are frequent targets of media bias allegations – have become “birthing centers for polarizing rhetoric.”[5] In the 21st century, modern Americans have access to a plethora of news sources, and the competition for audience and “the threat to journalistic business models” has changed the way political news is produced and consumed.[6] Cable news is a business that runs on ratings and advertisements and, in order to capture people’s attention, it needs to be engaging. It has, therefore, increasingly blurred the lines between information and entertainment. Fox News has established itself as the most-watched cable news network in the country by airing less news and more “opinions-about-the-news” to garner larger audiences.[7] While this may negatively affect the American political system, it is profitable for founder Rupert Murdoch.[8] To compete, MSNBC has “pumped up its ratings by recasting itself as a left-leaning riposte to Fox News.”[9] It is important to note that although both MSNBC and Fox have strong viewpoints and ‘opinion’ hosts, the former lives in the world of fact while the latter “spins its own reality.”[10] According to Jones “much of what we see on Fox News, especially in primetime, is not based in truth.”[11] Fox News is therefore deliberately misleading the public while causing dissension.[12]

Figure 2. Vox. Estimated ideology by channel year: Each point corresponds to the estimated ideology of the news channels based on phrase usage, with 95% confidence bounds shaded.

The divisive tone of cable news has become the very nature of its appeal, and this type of journalism hardens polarization because “the more political media one consumes, the more warped their perspective of the other side becomes.”[13] Partisans tend to view each other negatively because polarized media weaponizes the differences between political and social groups instead of emphasizing commonalities. This type of ‘identity journalism’ reinforces identity and binds people into communities. During the 2020 presidential election, Fox News’ Tucker Carlson – television’s most popular political host with an average of more than three million viewers a night – claimed that “the leaders of today’s Democratic Party despise this country… we cannot let them run this nation because they hate it. Imagine what they would do to it.”[14] His wording is carefully selected to categorize people into groups and create a shared sense of belonging to a threatened community. Byers believes that MSNBC also presents ideologically biased information, although in a less outrageous manner.[15] This tribal mentality – engrained in our evolutionary need to belong to a group – aims to oversimplify and distort “complex problems by dividing the world into an ‘us’ and a ‘them,’ vilifying the latter.”[16] This mindset can lead to irrational group favoritism and produce hostilities.

Polarization is further exacerbated by echo chambers, spaces where “the reinforcing effect of media and beliefs drive people to wall themselves off from a wider range of media.”[17] Having many news options available means that consumers can choose to hear messages that reinforce their beliefs while avoiding those from alternative points of view. For example, Fox News and MSNBC “only tell us how right we are, and that’s making us more extreme.”[18] The more media people see that encourages them to think of themselves as part of a group, the deeper their identity roots become engrained, and the more resistant they are to change their views. Therefore, Klein hypothesizes that the solution may be for liberals to watch more of Fox News and for conservatives to tune into MSNBC.[19] However, studies have shown that hearing contrary opinions drives partisans towards “not just a deeper certainty in the rightness of their cause but more polarized policy positions.”[20] Thus, rather than expanding viewpoints, hearing the other side’s rhetoric entrenches viewers further in their political identities, as all arguments are perceived as biased and duplicitous.

If left unchecked, cable news’s dissenting language and angry rhetoric will foster even stronger feelings of animosity toward the other side and impede any chances of conducting constructive conversations. It is important to note that certain partisans feel this way because they actively pay attention to politics and listen to cable news daily. The effects of partisan media on attitudes are concentrated primarily among those who already have extreme opinions. Although these shows may command a modest audience, they are influential because they have the right audience. Those who watch these shows drive politics, as they are more partisan and politically involved. Thus, “these programs contribute to polarization not by shifting the center of the ideological distribution, but rather by lengthening the tails.”[21]

Social Media

Most of the literature trying to explain how media bias affects voter opinion by generating misinformation and exacerbating political polarization has mainly focused on traditional media. However, there is increasing concern that social media sites are contributing to political polarization. The technology of communication in social media differs significantly from that of traditional broadcasting. While cable news communication is one-way, social media communication offers a two-way model, allowing anyone to easily produce and share content that immediately reaches global audiences. This makes it much more difficult for individuals to encounter accurate and reliable information online, as they observe “distilled signals from friends in their network without necessarily knowing the source.”[22] Concerns about the negative societal consequences of the online spread of misinformation became widespread after the 2016 presidential election, during which ‘fake news’ was widely circulated on social media. Gu et al. define ‘fake news’ as “the promotion and propagation of news articles via social media” that are “promoted in such a way that they appear to be spread by other users, as opposed to being paid-for advertising… designed to influence or manipulate users’ opinions on a certain topic towards certain objectives.”[23]

Social media platforms allow ‘fake news’ to be disseminated instantly on the internet and “amplified in partisan communities of like-minded individuals, where they go unchallenged due to ranking algorithms that filter out any dissenting voice.”[24] These algorithms skew the variety of information people encounter online in favor of information that only supports personal beliefs. As a result, “filter bubbles” may be formed and society may be more polarized ideologically, as it is less exposed to divergent viewpoints.[25] YouTube, whose algorithm like other platforms was designed to make people spend more time on the site, has radicalized people through inflammatory messaging. Facebook’s very structure creates “filter bubbles,” as users “have to ‘friend’ others to see their posts, meaning they’re less likely to see people outside of their real-life friends and family, who are more likely to have similar lives and viewpoints.”[26] This may reinforce their existing beliefs, and they may thus become more extreme.[27] According to Isaac & Ember, Facebook went so far as to tweak its algorithms after the 2016 election to “promote posts from friends and family, and show far fewer posts from news outlets, which likely further contributed to filter bubbles and division.”[28]

Figure 3. Pew Research Center

In addition to algorithms that favor engagement, internet bots artificially amplify misinformation.[29] Social bots, which pose as real human users on platforms such as Twitter, Reddit, Facebook, and YouTube “use behaviors like excessive posting, early and frequent retweeting of emerging news, and tagging or mentioning influential figures in the hope they will spread the content to their thousands of followers” and possibly alter their behavior.[30] A recent study found that 33% of the top shares of content from low-credibility sources were likely to be bots.[31] Therefore, humans are unknowingly contributing to the spread of misinformation by retweeting bots and fake news articles. The misinformation spread by bots can also be used to infiltrate political conversations. Leading up to the 2016 presidential election, 20 percent of all political tweets originated from bot accounts.[32] Though a majority of election-related social bots originated domestically,[33] the Mueller report confirmed Russian interference in the 2016 election via foreign social media bots that were spreading misinformation to the American public, further exacerbating the spread of political polarization in the U.S.[34]

Despite initial optimism that social media might enable people to consume more heterogeneous sources of information and lead to a more pluralistic debate, such forums exacerbate political polarization because of social network homophily.[35] ‘Fake news’ on social media is very difficult to detect, posing a challenge for social media users, moderators, and government agencies trying to mitigate its harmful effects.[36] A 2016 Pew Research Center study confirmed that 64 percent of U.S. adults say that “fabricated news stories cause a great deal of confusion about the basic facts of current events” and that they are unable to identify the bot as a source of misinformation, “implying that they cannot detect and disregard fake news.”[37] As a result of ideological polarization, “diversity of opinions and arguments may be compromised, people in extremely homogenous groups may ignore facts that would prove their arguments wrong, and dissemination of online disinformation may raise.”[38]

Threat to Democracy: January 6th, 2021

Wilson et al. argue that increases in “real institutional polarization among political elites, partisan media, and social media meaningfully account for the intensification of false polarization among the electorate.”[39] Additionally, “political elites have become both more polarized themselves and more incentivized to stoke polarization among voters, that partisan media selectively portrays political opponents in polarizing ways, and that via social media people actively contribute to shaping a political landscape that disproportionately reinforces and amplifies extremity and outrage.”[40] Politicians further exacerbate polarization by fueling it with vitriolic political campaigns to demonize opponents, activate anger, and increase party loyalty.

The rise in political polarization poses a threat to democracy. During the 2020 presidential election, political elites spread disinformation to falsely convince the American public that mail ballots would generate massive election fraud. Alongside Fox News and social media outlets, former President Trump repeatedly proclaimed that the election was stolen from him, and that Joe Biden’s victory was illegitimate.[41] On January 6th, 2021, Trump supporters “marched to the Capitol, smashed windows and doors, stormed the building, assaulted police officers, stole federal property, and temporarily stopped members of Congress from certifying Biden’s victory.”[42] This was the ultimate “polarization of Americans turning against other Americans and engaging in violence that resulted in death and injury.”[43] In an attempt to deflect blame, Trump supporters spread lies on social media and accused Antifa, the CIA, and others of committing the violent actions and the liberal media of falsely depicting the event.[44] These false narratives will reinforce existing beliefs that the system is unfair, and that the media are biased. If left unchecked, these beliefs “will affect views about the Biden presidency, the actions of a Democratic Congress, the condition of American democracy, and the future of the 2022 and 2024 elections.”[45]

Figure 4. Vox


Both traditional news and social media channels exacerbate the spread of misinformation and therefore increase polarization among the U.S. public and political elite. Divisive cable news has real consequences, as it creates a vicious cycle in which journalists cover politics in a more polarized way, anticipating a more polarized audience’s tastes, and creating a more polarized political reality. With the help of algorithms and bots, social media plays an important role in spreading misinformation and in allowing the public to “become an active participant in creating and selectively amplifying narratives that shape realities.”[46] This profoundly affects U.S. democracy and society because “it is hard to bring the country together when each side has its own facts and attributions of responsibility.”[47]

Social media platforms like Twitter have taken measures to mitigate the spread of misinformation, such as banning certain users’ posting privileges. However, this will likely not stop the spread of misinformation, as bots will continue sharing fake news on their profiles, and misinformation will thus “continue to divide Americans and poison our political environment.”[48] Policymakers could try to identify all bots and eliminate them from networks, but this would be difficult to implement. Another option would be to introduce a ‘counter bot’ that sends signals at the other end of the spectrum to counteract the first bot. However, this may further exacerbate polarization and induce gridlock. A more effective strategy would be to reduce the number of bot followers by training people on the detection of fake news.[49] West argues that lawmakers should “impose accountability on social media sites to protect Americans from exhortations of violence and outright hate speech.”[50] Additionally, cable news should aim to neutralize under a less controversial administration, allowing Americans to confront future challenges more effectively.

If the public polarizes further, political and media elites will continue to fuel the division. Although party disagreement is an essential part of the political process, “polarization and animosity based on misconceptions of the other side threatens to misdiagnose problems, leading people to battle imagined enemies and distracting from opportunities for transformative reform.”[51]



[1] Michael Dimock and Richard Wike, “America is exceptional in the nature of its political divide,” NY Times, November 13, 2020,

[2] Ibid.

[3] Ezra Klein, Why We’re Polarized (New York: Avid Reader Press, 2020).

[4] Andrew O’Donohue, ‘The Long Path of Polarization in the United States.’ In Democracies Divided: The Global Challenge of Political Polarization, edited by Carothers Thomas and O’Donohue Andrew, 65-92 (Washington, DC: Brookings Institution Press, 2019).

[5] Margaret Sullivan, “‘Birthing centers for polarizing rhetoric’: The outsize influence of Fox, CNN and MSNBC,” The Washington Post, May 26, 2019,

[6] Ezra Klein, Why We’re Polarized.

[7] Brian Stelter, “‘We turned so far right we went crazy:’ How Fox News was radicalized by its own viewers,” CNN Business, June 8, 2021,

[8] Ibid.

[9] Alessandra Stanley, “How MSNBC Became Fox’s Liberal Evil Twin,” The New York Times, August 31, 2012,

[10] Tom Jones, “No, Fox News and MSNBC are not the same thing,” Poynter, February 1, 2021,

[11] Ibid.

[12] Ibid.

[13] Ibid.

[14] David Bauder, “Fox News’ Tucker Carlson criticized for saying Democrats hate America,” Associated Press,

[15] Dylan Byers, ‘Is MSNBC worse than Fox News?’ Politico, December 9, 2013,

[16] Arash Emamzadeh, “‘The Psychology of “Us-vs-Them”’ Psychology Today,” Psychology Today,

[17] Jay D Hmielowski, Myiah J Hutchens, and Michael A Beam, “Asymmetry of Partisan Media Effects?: Examining the Reinforcing Process of Conservative and Liberal Media with Political Beliefs,” Political Communication 37, no. 6 (2020): 852-68.

[18] Ezra Klein, Why We’re Polarized.

[19] Ibid.

[20] Ibid.

[21] Matt Levendusky, “Are Fox and MSNBC polarizing America?” The Washington Post, February 3, 2014,

[22] Marina Azzimonti and Marcos Fernandes, “Social Media Networks, Fake News, and Polarization,” NBER Working Paper Series,

[23] Lion Gu, Vladimir Kropotov, and Fyodor Yarochkin, “The Fake News Machine,” Trend Labs,

[24] Joshua Tucker, Andrew Guess, Pablo Barberá, Cristian Vaccari, Alexandra Siegel, Sergey Sanovich, Denis Stukal, and Brendan Nyhan, “Social Media, Political Polarization, and Political Disinformation: A Review of the Scientific Literature,” SSRN,

[25] Eli Pariser, ‘Beware online filter bubbles,’ TED,

[26] Rani Molla, “Social media is making a bad political situation worse,” Vox, November 10, 2020,

[27] Cheuk Hang Au, Kevin K.W. Ho, and Chiu K.W. Dickson, “The Role of Online Misinformation and Fake News in Ideological Polarization: Barriers, Catalysts, and Implications,” Information Systems Frontiers, 2021,

[28] Mike Isaac and Sydney Ember, “Facebook to Change News Feed to Focus on Friends and Family,” The New York Times, June 29, 2016,

[29] Tucker et al, “Social Media, Political Polarization, and Political Disinformation: A Review of the Scientific Literature.”

[30] Chengcheng Shao, Giovanni Luca Ciampaglia, Onur Varol, Kai-Cheng Yang, Alessandro Flammini, and Filippo Menczer, “The spread of low-credibility content by social bots,” Nature Communications 9, 4787,

[31] Ibid.

[32] Alessandro Bessi and Emilio Ferrara, “Social bots distort the 2016 US Presidential election online discussion. First Monday,” First Monday, Volume 21, Number 11 – 7 November 2016,

[33] Ludovic Rheault & Andreea Musulan, “Efficient detection of online communities and social bot activity during electoral campaigns,” Journal of Information Technology & Politics, 18:3, 324-337, DOI: 10.1080/19331681.2021.1879705.

[34] Robert S. Mueller, “Report on the investigation into Russian interference in the 2016 presidential election,” US Department of Justice, March 2019,

[35] Christopher A. Bail, Lisa P. Argyle, Taylor W. Brown, John P. Bumpus, Haohan Chen, M. B. Fallin Hunzaker, Jaemin Lee, Marcus Mann, Friedolin Merhout, and Alexander Volfovsky, “Exposure to opposing views on social media can increase political polarization,” PNAS, September 11, 2018,

[36] Marina Azzimonti and Marcos Fernandes, “Social Media Networks, Fake News, and Polarization.”

[37] Michael Barthell, Amy Mitchell, and Jesse Holcomb, “Many Americans Believe Fake News Is Sowing Confusion,” Pew Research Center, December 15, 2016,

[38] Cheuk Hang Au et al, “The Role of Online Misinformation and Fake News.”

[39] Anne E Wilson, Victoria A Parker, Matthew Feinberg, “Polarization in the contemporary political and media landscape,” Current Opinion in Behavioral Sciences, Volume 34 2020, Pages 223-228, ISSN 2352-1546,

[40] Ibid.

[41] Darrell M. West, “The Role of Misinformation in Trump’s Insurrection,” Brookings Institute, January 11, 2021,

[42] Ibid.

[43] Ibid.

[44] Michael M. Grynbaum, Davey Alba and Reid J. Epstein, “How Pro-Trump Forces Pushed a Lie About Antifa at the Capitol Riot,” NY Times, March 1, 2021,

[45] Ibid.

[46] Renée DiResta, “It’s Not Misinformation. It’s Amplified Propaganda,” The Atlantic, October 9, 2021,

[47] Darrell M. West, “The Role of Misinformation in Trump’s Insurrection.”

[48] Ibid.

[49] Marina Azzimonti and Marcos Fernandes, “Social Media Networks, Fake News, and Polarization.”

[50] Darrell M. West, “The Role of Misinformation in Trump’s Insurrection.”

[51] Anne E Wilson et al, “Polarization in the contemporary political and media landscape.”