Abramowitz, A. I. (2010). The Disappearing Center: Engaged Citizens, Polarization, and American Democracy. Yale University Press.

This book provides valuable insights into how polarization affects governance and democratic engagement in American politics. Abramowitz argues that the electorate is increasingly divided along partisan lines, leading to a more contentious and gridlocked political environment.

Abramowitz, A. I., & Saunders, K. L. (2008). Is Polarization a Myth? The Journal of Politics, 70(2), 542–555. https://doi.org/10.1017/s0022381608080493.

Abramowitz and Saunders used data from voting behavior and political participation to suggest that ideological polarization has increased among the mass public as well as among the political elites. The authors directly countered political scientist Morris P. Fiorina’s prior argument that citizens are uninterested and disengaged in politics and therefore, ideological polarization has not occurred among the general population.

Cinelli, M., Etta, G., Avalle, M., Quattrociocchi, A., Di Marco, N., Valensise, C., Galeazzi, A., & Quattrociocchi, W. (2022). Conspiracy theories and social media platforms. Current Opinion in Psychology, 47. https://doi.org/10.1016/j.copsyc.2022.101407. 

The researchers contend that echo chambers and group polarization result in the proliferation and spread of conspiracy theories online. They provide an overview of various social media platforms and the way their affordances help to create these echo chambers, which is a pivotal element of communication around conspiracy theories.

Enjolras, B., & Salway A. (2023). Homophily and polarization on political twitter during the 2017 Norwegian election. Social Network Analysis and Mining, 13(1), 10. https://doi.org/10.1007/s13278-022-01018-z. 

The authors talked about ideological homophily, which is defined as how people tend to seek out like-minded individuals to surround themselves with. This notion is a contributing factor to the formation of group polarization and echo chambers, as individuals then reinforce their own beliefs through conversations with their in-group.

Ferguson, N. (2017, August 15). The False Prophecy of Hyperconnection. Foreign Affairs. https://www.foreignaffairs.com/world/false-prophecy-hyperconnection.

This article argues that even though the world is more connected as ever before, the social media echo chambers have led to greater polarization online as we tend to surround ourselves with people who have similar beliefs as our own instead of seeking out new ideas and opinions.

Fiorina, M. P. (2013, February 12). America’s Missing Moderates: Hiding in Plain Sight. The American Interest. https://www.the-american-interest.com/2013/02/12/americas-missing-moderates-hiding-in-plain-sight/.

Fiorina argues that polarization has not occurred because moderates are still present in our society, and that many voters are now flighty and uncommitted. Despite gradual demographic shifts, the characteristics of the American electorate have changed very little while the political elites have changed and polarized at a much greater rate.

Hacker, J. S., & Pierson, P. (2015). Confronting Asymmetric Polarization. In N. Persily (Ed.), Solutions to Political Polarization in America (pp. 59-70). chapter, Cambridge: Cambridge University Press. 

This article contends that discussions regarding the theory of polarization have been flawed because it claims that polarization is happening at a similar rate on both sides. The authors summarize evidence that contemporary polarization is asymmetric and occurring at a faster rate on one side than the other.

Iyengar, S., Gaurav S., Lelkes, Y. (2012). Affect, Not Ideology: A Social Identity Perspective on Polarization. Public Opinion Quarterly, 76(3), 405-431. https://doi.org/10.1093/poq/nfs038.

The authors posit a different definition of polarization based on emotions instead of policy. They present findings that show that each side of the spectrum increasingly dislikes and distrusts their opponents.

Jackson, J. W., & Hinsz, V. B. (2022). Group dynamics and the U.S. Capitol insurrection: An introduction to the special issue. Group Dynamics: Theory, Research, and Practice, 26(3), 169-177. https://doi.org/10.1037/gdn0000193.

The article talks about how group dynamics like group polarization has contributed to the insurrection and other related extremist events, thus providing insights on how such events can be prevented and how tensions that follow such events can be alleviated.

Kubin, E., & von Sikorski, C. (2021). The role of (social) media in political polarization: a systematic review. Annals of the International Communication Association, 45(3), 188-206. https://doi.org/10.1080/23808985.2021.1976070

The study systematically reviews 94 articles on the relationship between social media and political polarization, identifying a surge in research over the past decade. Key findings include the role of pro-attitudinal media in exacerbating polarization and inconsistent definitions of ideological and affective polarization, with recommendations for future research to address these gaps and explore depolarization strategies.

Levendusky, M. S. (2009). The Microfoundations of Mass Polarization. Political Analysis, 17(2), 162–176. http://www.jstor.org/stable/25791966.

Levendusky created a statistical model to provide evidence that the occurrence of individual-level conversions of Democrats and Republicans will slowly contribute to generate mass polarization.

Mason, L., & Wronski, J. (2018). One Tribe to Bind Them All: How Our Social Group Attachments Strengthen Partisanship. Advances in Political Psychology, 39(1), 257-277. https://doi.org/10.1111/pops.12485

The authors define the term “social sorting,” which describes how people’s social identities, like race or religion, increasingly align with their political party, intensifying loyalty to their party and reducing tolerance for opposing groups.

McCoy, J., & Press, B. (2022, January 18). What Happens When Democracies Become Perniciously Polarized? Carnegie Endowment for International Peace. https://carnegieendowment.org/research/2022/01/what-happens-when-democracies-become-perniciously-polarized?lang=en.

The authors discuss the impact of political polarization in democracies around the world, painting a picture of what could happen to the United States if this level of divisiveness continues. The article shows how many democracies have descended into authoritarianism due to the level of political polarization they experienced.

Pew Research Center. (2014, June 12). Political Polarization in the American Public [Report]. https://www.pewresearch.org/politics/2014/06/12/political-polarization-in-the-american-public/.

Pew surveyed 10,000 adults nationwide to find that polarization has been occurring at a greater rate than ever before, and that it goes beyond mere dislike but an extreme fear and distrust of the other side.

Renström, E. A., Bäck, H., Carroll, R. (2023) Threats, Emotions, and Affective Polarization. Political Psychology, 44(6), 1337-1366. https://doi.org/10.1111/pops.12899.

This study found that anger, more than fear or anxiety, strengthens negative feelings between political groups, increasing polarization. Some people feel hostile toward supporters of other political parties when they see them as a threat to their own group, especially if this perception triggers anger.

Smith, L. G. E., Thomas, E. F., Bliuc, A., & McGarty, C. (2024). Polarization is the psychological foundation of collective engagement. Communications Psychology 2(41), 1-13. https://doi.org/10.1038/s44271-024-00089-2.

The researchers found that group polarization strengthens political polarization because social interactions, like those on social media, help people form shared identities with stronger, unified beliefs, which can motivate collective action.

Stoddard, J., & Hess, D. E. (2024). The Effects of Political Polarization on Social Studies Education and What We Should Do. Social Education, 88(1), 11-12. https://www.socialstudies.org/88/1/effects-political-polarization-social-studies-education-and-what-we-should-do. 

This article clearly defined political polarization and how it has impacted teaching and learning in schools around the United States. The authors talk about how many districts have started limiting discussions surrounding political issues because of how divisive it can be, leading to a decline in healthy discussions surrounding civic education.

Sunstein, C. R. (2009). Going to Extremes: How Like Minds Unite and Divide. Oxford University Press.

Sunstein posits a theory regarding group polarization, where whenever a group of like-minded people will generally become more extreme and polarized when they discuss issues with one another. He provides real-world examples in the context of politics and beyond to show how and why people turn towards an extremist mentality.

Sunstein, C. R. (2017). #Republic: Divided Democracy in the Age of Social Media. Princeton University Press.

Sunstein expands on his previous research regarding group polarization in the context of digital and social media, stating that digital technologies are contributing to political polarization through echo chambers. He argues that these platforms allow individuals to filter information in ways that reinforce their existing beliefs and reduce exposure to diverse perspectives.

Westfall, J., Van Bowen, L., Chambers, J. R., & Judd, C.M. (2015). Perceiving Political Polarization in the United States: Party Identity Strength and Attitude Extremity Exacerbate the Perceived Partisan Divide. Perspectives on Psychological Science, 10(2), 145-158. http://www.jstor.org/stable/44290057. 

The researchers argue that people tend to overestimate the differences between Democrats and Republicans, seeing more political polarization than actually exists. This perception is stronger among those who identify closely with a party, hold extreme views, or actively engage in political activities like voting and campaigning, with these patterns occurring across both parties.