Towards global equity in political polarization research
Max Falkenberg, Matteo Cinelli, Alessandro Galeazzi, Christopher A. Bail, Rosa M Benito, Axel Bruns, Anatoliy Gruzd, David Lazer, Jae K Lee, Jennifer McCoy, Kikuko Nagayoshi, David G Rand, Antonio Scala, Alexandra Siegel, Sander van der Linden, Onur Varol, Ingmar Weber, Magdalena Wojcieszak, Fabiana Zollo, Andrea Baronchelli, Walter Quattrociocchi
*Corresponding authors:
Abstract
With a folk understanding that political polarization refers to socio-political divisions within a society, many have proclaimed that we are more divided than ever. In this account, polarization has been blamed for populism, the erosion of social cohesion, the loss of trust in the institutions of democracy, legislative dysfunction, and the collective failure to address existential risks such as Covid-19 or climate change. However, at a global scale there is surprisingly little academic literature which conclusively supports these claims, with half of all studies being U.S.-focused. Here, we provide an overview of the global state of research on polarization, highlighting insights that are robust across countries, those unique to specific contexts, and key gaps in the literature. We argue that addressing these gaps is urgent, but has been hindered thus far by systemic and cultural barriers, such as regionally stratified restrictions on data access and misaligned research incentives. If continued cross-disciplinary inertia means that these disparities are left unaddressed, we see a substantial risk that countries will adopt policies to tackle polarization based on inappropriate evidence, risking flawed decision-making and the weakening of democratic institutions. Introduction
Researchers have gone to great lengths to understand the causes and consequences of political polarization in the United States, especially since Donald Trump’s first election to the Presidency in 2016. However, a comparable evidence-base for understanding polarization outside the U.S. remains limited. If insights from the U.S. were to generalize to other regions, the lack of localized evidence could, perhaps, be tolerated. However, as we will outline, there are numerous results from the U.S. which are outliers when viewed in a global context. Ensuring a globally relevant literature on political polarization is, or should be, a fundamental goal for the academic community. Yet substantial systemic and cultural barriers exist. First, how polarization is studied is often influenced by norms established in U.S.-focused
1 Central European University, Austria. 2 CNR-ISC, UoS Sapienza, Rome, Italy. 3 University of Padova, Italy. 4 Duke University, USA. 5 Universidad Politécnica de Madrid, Spain. 6 Queensland University of Technology, Australia. 7 Toronto Metropolitan University, Canada. Northeastern, USA. Sungkyunkwan University, South Korea. Georgia State University, USA. University of Tokyo, Japan. MIT, USA. University of Colorado Boulder, USA. University of Cambridge, UK. Sabanci University, Turkiye. Saarland University, Germany. University of Warsaw, Poland. University of California San Diego, USA. Ca’ Foscari Venice, research. Second, academic incentives are influenced by top interdisciplinary journals consistently favouring U.S.-focused research and reviews over work from other regions (SM). Finally, high quality polarization research is contingent on high quality data, but access to this data has become increasingly difficult, and is sometimes only available to U.S.-based researchers (SM). To address these issues, this article offers an overview of polarization research globally, highlighting key trends in ideological and affective polarization, the influence of socio-economic factors, and the impact of news and social media. Parts of this literature may seem disconnected, but this is a further reflection of the disciplinary fragmentation of polarization
research. Drawing from a growing set of examples, we discuss key results in the literature that are country-specific and those that, broadly speaking, generalize across a wide range of nations. We also highlight key areas where globally relevant literature is lacking, and provide recommendations for advancing towards a more globally equitable understanding of polarization. A failure to address these gaps is not only potentially dangerous, risking inefficient or counterproductive polarization interventions, but is intellectually complacent, further deepening existing inequities in our global understanding of polarization. Figure 1: The unequal distribution of polarization research. Academic papers on political polarization which refer to a specific country overwhelmingly reference the United States. In total, 2,341 papers use the term “political polarization” (or “political polarisation”) in their title or abstract of which 1,309 refer to at least 1 country. The United States is mentioned in 650 papers. Many papers which do not mention a country are U.S. focused, but do not state so explicitly. See SM for details. Box 1: The normative U.S. framing of polarization. In selecting “polarization” as their word of 2024, Merriam-Webster defined polarization as “division into two sharply distinct opposites; especially, a state in which the opinions, beliefs, or interests of a group … become concentrated at opposing extremes”. While such a framing may be appropriate for the public’s understanding of the U.S.’s unusual Manichean two-party democracy, there are many cases where such a framing may not be appropriate. For instance, it is far from clear how polarization should be understood and measured in multi-party democracies, or in the absence of pluralist party systems where the opposition to an authoritarian regime is hard to measure (SM). Similarly, there is substantial work discussing how polarization can be formulated without explicit reference to the extremes, changing how the concept is interpreted. While such issues can seem abstract, they can directly affect the global context for understanding polarization when, for example, cross-country political surveys ask individuals to place themselves ideologically on a one-dimensional left-right scale, when other axes of political belief may be equally important (e.g., the establishment-anti establishment dimension; SM).
Global trends in polarization
Historically, scholars have focused largely on the study of ideological polarization, typically understood as the gap between liberals and conservatives, and by extension between the political left and right (SM). In contrast, since the late 2000s, evidence from the U.S. that animosity between political opponents has grown disproportionately relative to policy differences has led researchers to shift focus away from ideological polarization and towards affective polarization: the phenomenon whereby an individual has negative feelings towards their political out-group (and/or positive feelings towards their in-group). Amongst political elites, comparative data from 21 high-income countries reveals a small but significant increase in elite ideological polarization, with Canada and Australia cited as countries with low ideological polarization, in contrast to Spain, Italy and Sweden where ideological polarization is high (SM). However, at a global scale, ideological polarization does not appear to have increased amongst the mass public. This is in contrast to the trend observed in the United States where growing ideological polarization (both mass and elite) is now well documented (SM). Such increases are, however, typically smaller than the variability observed across countries. In the United States, the state of affective polarization has been described as “political sectarianism”, drawing parallels to religious and ethnic sectarianism, and having often been linked to the rise of populism (SM).
Referencing data from 12 OECD countries, Finkel et al. argue that the state of U.S. affective polarization is exceptional, with the U.S. having suffered the largest increase in affective polarization over the last 40 years,. However, estimates of the absolute levels of affective polarization from 53 countries point towards countries such as Türkiye, Hungary, and Kenya as examples of high affective polarization, and the Philippines, the Netherlands, Belgium, and Japan as examples of countries with low levels of affective polarization, with the U.S. falling in the middle of the pack. For many countries (including authoritarian states, where measuring polarization is particularly challenging; SM) quantitative estimates of affective polarization are still unavailable (SM). The relationship between ideological and affective polarization
In the United States, the relationship between ideological and affective polarization is debated, rooted in the question of whether policy differences drive partisan animosity (SM). This debate draws parallels globally, where the evidence for their relationship is mixed. Ideological and affective polarization are broadly correlated, but some countries display significant ideological polarization without high out-party animosity (e.g., the Netherlands), while others are afflicted with severe affective polarization despite the principal parties being largely moderate (e.g., Montenegro and Serbia). Importantly, survey evidence from 53 countries suggests that high levels of affective polarization are correlated with democratic backsliding, but high levels of ideological polarization are not. The reasons for country-level differences in the relationship between ideological and affective polarization are complex: The U.S.-centric literature has made a two-party “us-vs-them” framing of polarization the norm, but in multi-party states it is not uncommon for individuals to have positive (or negative) feelings towards multiple parties. Not only does this complicate how to measure polarization, it also introduces new political dynamics which can have both positive and negative impacts, for instance, related to the sustainability and effectiveness of coalition governments. In this context, research suggests that affective polarization is higher in majoritarian political systems where power is concentrated in the hands of a single party (e.g., France, UK) than in systems based on consensual governance (e.g., Switzerland, the Netherlands), while the opposite trend is observed for ideological polarization (SM). Socio-economic factors (SM) and income inequality are also implicated as key drivers of polarization. Evidence from 20 Western democracies (Europe, USA, Canada, New Zealand, Australia) shows that affective polarization is worse when levels of income inequality and unemployment are high. But, again, countries with high income inequality show lower levels of ideological polarization amongst the mass public (e.g., the U.S.) than lower income inequality countries (e.g., Sweden; SM). Finally, it is often assumed that polarization has roots in ethnic or religious differences. However, while these factors may correlate with observed differences in polarization, and may be used as the basis of polarizing strategies by political leaders (e.g., in the U.S., Hungary, or Türkiye), multiple comparative studies have shown that social cleavages do not, inherently, predict damaging forms of polarization (SM). Polarization and information exposure
The role of the news media. Partisan news media are often blamed for increasing polarization, but evidence to support this assertion is mixed and beset by technical issues and geographic limitations. Again, the available literature is heavily U.S.-centric and the role of the news media in developing countries or in autocracies is rarely considered. Most studies on the polarizing role of the news media concern either the supply side of the news – how the news media ecosystem is aligned with specific political ideologies – or the reception side – namely what news individuals consume. Addressing the former, Western news media systems have been categorized according to “political parallelism”, referring to the one-to-one correspondence between news outlets and political parties (SM). Using this framework, countries were classified as having low levels of political parallelism (e.g., the U.S., UK, Ireland), high levels but lowering over time (e.g. Austria, Belgium, Finland, Germany), or sustained high levels (e.g., Italy, France, Spain, Greece), revealing substantial differences in the politicization of the news media across developed countries. With regard to the consumption side, the proliferation of the internet has enabled easy access to increasingly diverse online content, some of which is highly partisan or radical (SM). Nevertheless, survey self-reports in 12 developed countries suggest that the majority consume largely centrist and moderate news, both on- and offline, despite (largely unfounded) fears that social media algorithms and “filter bubbles” will drive users to more radical content (SM). The U.S. has the most partisan consumption, and individual communities do have a highly skewed news media diet (more so in the U.S. than other countries; SM), but absolute levels of partisan news consumption remain low. It is also not clear how to compare these results to countries where the politicization of the news media is more explicit, including authoritarian states where news outlets are forced to support the regime in power or risk political backlash (SM). Questions of news supply and demand do not answer whether the news media impact polarization in the general population.
Limited survey-based and experimental evidence from the U.S. and Israel suggests that exposure to partisan news outlets and their messages reinforces prior political attitudes and affective polarization (SM). However, given the challenges in measuring exposure to (partisan) media using self-reports and in ascertaining their effects outside experimental settings, this research may not portray the role of the news media in the “real world” accurately (SM). Additionally, the global loss of trust in the news, and very low engagement with news media content in general, mean that researchers are increasingly questioning the polarizing role of the news media (SM). The role of the internet & social media. The internet and social media continue to play a dominant role in how citizens consume content. Despite this, claims of social media’s negative impacts are often anecdotal, or based on correlational evidence, and there are substantial differences across countries in the extent to which social media is seen as democratically harmful (Americans see social media as far more damaging than other surveyed populations; SM). With a focus on user-user interactions, one perspective argues that social media drive polarization by enabling politically engaged users to primarily interact with other ideologically aligned individuals – a pattern observed across many platforms and countries – indicative of an epistemic bubble, or echo chamber, where ideological views and out-group affect may become more extreme (SM). However, another perspective argues that these homophilous interaction patterns do not constitute ideological isolation. First, social media interactions in most countries are not primarily with political actors or content (SM). Second, when individuals interact with news content rather than individuals, their news diet is often politically moderate (see above). Third, while certain interaction types (like reposts) give the appearance of isolated communities, other interaction types (mentions or follows) reveal that out-group interaction is not so rare (SM), albeit these interactions are often toxic attacks (a feature common across many countries; SM). Finally, even if online interactions are ideologically homogeneous, individuals’ may in fact be more isolated in their offline environments (SM), a factor likely to be highly country- and context-dependent.
Whether biased information exposure on social media leads groups to adopt more extreme views is debated (SM). The largest Facebook field experiment to date – a collaboration with Meta which was limited to U.S. researchers (SM) – finds that reducing users' exposure to content from like-minded sources does not measurably affect affective polarization or ideological extremity. However, similar research (with smaller study sizes) suggests that such results are likely to be country-dependent: One U.S. study found that deactivating Facebook reduced both ideological and affective polarization, while a replication in Bosnia-Herzegovina found an increase in polarization (SM), with evidence to suggest that this unexpected increase may be related to individuals’ lack of offline exposure to other ethnicities. Critically, the question of whether social media is polarizing is linked to questions regarding the role of social media algorithms, the growing influence of AI, and how the internet is regulated. While our understanding of these factors is still at a very early stage, it is clear that they are likely to impact the polarizing role of the internet in different ways across countries (SM). Moving forward: The global challenge of countering polarization.
Preventing the potential damaging societal impacts of political polarization requires effective and long lasting interventions. However, the current dominance of U.S. research has put an outsized emphasis on developing interventions for affective polarization between Democrats and Republicans in the U.S. (SM), with few interventions having been tested elsewhere. Relying on such narrowly designed measures risks introducing inappropriate or even counterproductive solutions in diverse societal and cultural contexts. Fortunately, scholars are increasingly aware of the need to study interventions globally, with several projects already underway (for example [globalsocialmediastudy.com](https://globalsocialmediastudy.com/) and [templetonworldcharity.org/LLPW). However, the impact of these studies risks remaining limited](http://templetonworldcharity.org/LLPW) without systemic and cultural changes in how polarization research is produced and
communicated. Researchers working on understudied regions often face career disadvantages due to the perceived lack of visibility, relevance, and therefore impact, of their work. Academic institutions, publishers, and policymakers must actively promote and reward work that brings global balance to polarization research. This is not a call for less research on the U.S., which will remain well-funded and prolific, but rather to increase recognition and support for research that expands our understanding to include diverse global perspectives. A first step to improving the current state, given the constraints on academic resources, is to prioritize comparative research that identifies both shared and unique aspects of polarization across different countries. As part of this, it is crucial that country-specific research avoids over-generalizing their results.
For example, journals could mandate that studies focusing solely on the U.S. explicitly state this in their title or abstract (many currently don’t), as is commonplace for research focusing on almost any other country. To prevent further global disparities in polarization research, we argue that researchers must push back against growing restrictions on data access now. Since 2023, several social media companies (including Meta, X, Reddit) have shuttered academic access to their platforms’ data, and new opportunities for data access such as the European Union’s Data Services Act remain largely unproven (SM). Overcoming these challenges is essential for adopting truly global approaches to studying polarization. Finally, as our understanding of polarization evolves and new interventions are developed, both academics and policymakers must account for the unique regulatory and practical challenges of each country (SM). Interventions must be both ethically and practically tailored to the local context. We cannot assume that societies outside the U.S. – where empirical evidence is comparably limited – face the same problems which can be solved with the same solutions. Academics play a critical role in gathering evidence to better understand how polarization manifests across countries, but the implementation of interventions is necessarily political and often controversial. These decisions must rest with local stakeholders and decision makers.