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Why are prominent news media retractions so rare? Using data from a survey experiment in which respondents view simulated Twitter newsfeeds, we demonstrate the dilemma facing news organizations that have published false information. Encouragingly, media retractions are effective at informing the public – they increase the accuracy of news consumers’ beliefs about the retracted reporting more than information from third parties questioning the original reporting or even the combination of the two. However, trust in the news outlet declines after a retraction, though this effect is small both substantively and in standardized terms relative to the increase in belief accuracy. This reputational damage persists even if the outlet issues a retraction before a third party questions the story. In a social media environment that frequently subjects reporting to intense scrutiny, the journalistic mission of news organizations to inform the public will increasingly conflict with organizational incentives to avoid admitting error.

Policy Points Mass vaccination is essential for bringing the COVID-19 pandemic to a close, yet substantial disparities remain between whites and racial and ethnic minorities within the United States. Online messaging campaigns featuring expert endorsements are a low-cost way to increase vaccine awareness among minoritized populations, yet the efficacy of same-race/ethnicity expert messaging in increasing uptake remains unknown. Our preregistered analysis of an online vaccine endorsement campaign, which randomly varied the racial/ethnic identity of the expert, revealed no evidence that information from same race/ethnicity experts affected vaccine interest or the intention to vaccinate. Our results do not rule out the possibility that other low-cost endorsement campaigns may be more effective in increasing vaccine uptake, but do suggest that public health campaigns might profitably focus on issues of access and convenience when targeting minoritized populations in the United States.The COVID-19 pandemic in the United States has been unequally experienced across racial and ethnic groups. Mass vaccination is the most effective way to bring the pandemic to an end and to manage its public health consequences. But the racialization of public health delivery in the United States has produced a sizable racial/ethnic gap in vaccination rates. Closing this gap in vaccine uptake is therefore essential to ending the pandemic.We conducted a preregistered, well-powered (N = 2,117) between-subjects survey experiment, fielded March 24 to April 5, 2021, in which participants from YouGov's online panel-including oversamples of Black (n = 471), Hispanic/Latino/a (n = 430), and Asian American (n = 319) participants-were randomly assigned to see COVID-19 vaccine information endorsed by same- or different-race/ethnicity experts or to a control condition. We then measured respondents' vaccination intentions, intention to encourage others to get vaccinated, and interest in learning more information and sharing information with others.Same-race/ethnicity expert endorsements had no measurable effect on nonwhite or white respondents' willingness to get the COVID-19 vaccine, to encourage others to get the vaccine, or to learn more or share information with others.Our study provides empirical evidence suggesting online endorsements from same-race/ethnicity experts do not increase vaccine interest, advocacy, or uptake, though same-race/ethnicity endorsements may be effective in other venues or mediums.

Widespread misperceptions about COVID-19 and the novel coronavirus threaten to exacerbate the severity of the pandemic. We conducted preregistered survey experiments in the United States, Great Britain, and Canada examining the effectiveness of fact-checks that seek to correct these false or unsupported misperceptions. Across three countries with differing levels of political conflict over the COVID-19 response, we demonstrate that fact-checks reduce targeted misperceptions, especially among the groups who are most vulnerable to these claims, and have minimal spillover effects on the accuracy of other beliefs about COVID-19. However, the positive effects of fact-checks on the accuracy of respondents’ beliefs fail to persist over time in panel data even after repeated exposure. These results suggest that fact-checks can successfully change the beliefs of the people who would benefit from them most but that their effects are disappointingly ephemeral.

Although experiments show that exposure to factual information can increase factual accuracy, the public remains stubbornly misinformed about many issues. Why do misperceptions persist even when factual interventions generally succeed at increasing the accuracy of people’s beliefs? We seek to answer this question by testing the role of information exposure and decay effects in a four-wave panel experiment (n= 2,898 at wave 4) in which we randomize the media content that people in the United States see about climate change. Our results indicate that science coverage of climate change increases belief accuracy and support for government action immediately after exposure, including among Republicans and people who reject anthropogenic climate change. However, both effects decay over time and can be attenuated by exposure to skeptical opinion content (but not issue coverage featuring partisan conflict). These findings demonstrate that the increases in belief accuracy generated by science coverage are short lived and can be neutralized by skeptical opinion content.

Though prior studies have analyzed the textual characteristics of online comments about politics, less is known about how selection into commenting behavior and exposure to other people’s comments changes the tone and content of political discourse. This article makes three contributions. First, we show that frequent commenters on Facebook are more likely to be interested in politics, to have more polarized opinions, and to use toxic language in comments in an elicitation task. Second, we find that people who comment on articles in the real world use more toxic language on average than the public as a whole; levels of toxicity in comments scraped from media outlet Facebook pages greatly exceed what is observed in comments we elicit on the same articles from a nationally representative sample. Finally, we demonstrate experimentally that exposure to toxic language in comments increases the toxicity of subsequent comments.

In November 2020, Georgia Republican Marjorie Taylor Greene became the first open supporter of QAnon to be elected to the United States Congress. Despite criticism from Democrats, Republicans, and the media for her belief in this dangerous conspiracy theory, Greene remains a prominent national figure and a member of Congress. In a large survey experiment examining the effects of criticisms of Greene by different sources, we found that criticism of Greene from a Republican or a Democratic official reduced positive feelings toward QAnon but not Greene herself. However, unsourced criticisms and criticisms from media figures failed to measurably affect feelings toward either Greene or QAnon. Our results suggest that public officials have a unique responsibility to criticize misinformation, but they also highlight the difficulty in shifting attitudes toward politicians who embrace and spread falsehoods.

Does information about how other people feel about COVID-19 vaccination affect immunization intentions? We conducted preregistered survey experiments in Great Britain (5,456 respondents across 3 survey waves from September 2020 to February 2021), Canada (1,315 respondents in February 2021), and the state of New Hampshire in the United States (1,315 respondents in January 2021). The experiments examine the effects of providing accurate public opinion information to people about either public support for COVID-19 vaccination (an injunctive norm) or public beliefs that the issue is contentious. Across all 3 countries, exposure to this information had minimal effects on vaccination intentions even among people who previously held inaccurate beliefs about support for COVID-19 vaccination or its perceived contentiousness. These results suggest that providing information on public opinion about COVID vaccination has limited additional effect on people’s behavioral intentions when public discussion of vaccine uptake and intentions is highly salient.

Studies of the American public demonstrate that partisans often diverge not only on questions of opinion but also on matters of fact. However, little is known about partisan divergence in factual beliefs among the government officials who make real policy decisions, or how it compares to belief polarization among the public. This letter describes the first systematic comparison of factual belief polarization between the public and government officials, which we conducted using a paired survey approach. The results indicate that political elites are consistently more accurately informed than the public across a wide range of politically contentious facts. However, this increase in accuracy does not translate into reduced factual belief polarization. These findings demonstrate that a more informed political elite does not necessarily mitigate partisan factual disagreement in policy making.

Although commentators frequently warn about echo chambers, little is known about the volume or slant of political misinformation that people consume online, the effects of social media and fact checking on exposure, or the effects of political misinformation on behaviour. Here, we evaluate these questions for websites that publish factually dubious content, which is often described as fake news. Survey and web-traffic data from the 2016 US presidential campaign show that supporters of Donald Trump were most likely to visit these websites, which often spread through Facebook. However, these websites made up a small share of people’s information diets on average and were largely consumed by a subset of Americans with strong preferences for pro-attitudinal information. These results suggest that the widespread speculation about the prevalence of exposure to untrustworthy websites has been overstated. Guess, Nyhan and Reifler find that untrustworthy websites made up a small share of people’s information diets before the 2016 US election and were largely consumed by a subset of Americans with strong preferences for pro-attitudinal information.

Widespread misperceptions about COVID-19 and the novel coronavirus threaten to exacerbate the severity of the pandemic. We conducted preregistered survey experiments in the United States, Great Britain and Canada examining the effectiveness of fact-checks that seek to correct these false or unsupported beliefs. Across three countries with differing levels of political conflict over the pandemic response, we demonstrate that fact-checks reduce targeted misperceptions, especially among the groups who are most vulnerable to these claims, and have minimal spillover effects on the accuracy of related beliefs. However, these reductions in COVID-19 misperception beliefs do not persist over time in panel data even after repeated exposure. These results suggest that fact-checks can successfully change the COVID-19 beliefs of the people who would benefit from them most but that their effects are ephemeral.

Social media has increasingly enabled “fake news” to circulate widely, most notably during the 2016 U.S. presidential campaign. These intentionally false or misleading stories threaten the democratic goal of a well-informed electorate. This study evaluates the effectiveness of strategies that could be used by Facebook and other social media to counter false stories. Results from a pre-registered experiment indicate that false headlines are perceived as less accurate when people receive a general warning about misleading information on social media or when specific headlines are accompanied by a “Disputed” or “Rated false” tag. Though the magnitudes of these effects are relatively modest, they generally do not vary by whether headlines were congenial to respondents’ political views. In addition, we find that adding a “Rated false” tag to an article headline lowers its perceived accuracy more than adding a “Disputed” tag (Facebook’s original approach) relative to a control condition. Finally, though exposure to the “Disputed” or “Rated false” tags did not affect the perceived accuracy of unlabeled false or true headlines, exposure to a general warning decreased belief in the accuracy of true headlines, suggesting the need for further research into how to most effectively counter false news without distorting belief in true information.

Background: The duration and impact of the COVID-19 pandemic depends in a large part on individual and societal actions which is influenced by the quality and salience of the information to which they are exposed. Unfortunately, COVID-19 misinformation has proliferated. To date, no systematic efforts have been made to evaluate interventions that mitigate COVID-19-related misinformation. We plan to conduct a scoping review that seeks to fill several of the gaps in the current knowledge of interventions that mitigate COVID-19-related misinformation.Methods: A scoping review focusing on interventions that mitigate COVID-19 misinformation will be conducted. We will search (from January 2020 onwards) MEDLINE, EMBASE, CINAHL, PsycINFO, Web of Science Core Collection, Africa-Wide Information, Global Health, WHO Global Literature on Coronavirus Disease Database, WHO Global Index Medicus, and Sociological Abstracts. Grey literature will be identified using Disaster Lit, Google Scholar, Open Science Framework, governmental websites and preprint servers (e.g. EuropePMC, PsyArXiv, MedRxiv, JMIR Preprints). Study selection will conform to Joanna Briggs Institute Reviewers’ Manual 2020 Methodology for JBI Scoping Reviews. Only English language, original studies will be considered for inclusion. Two reviewers will independently screen all citations, full-text articles, and abstract data. A narrative summary of findings will be conducted. Data analysis will involve quantitative (e.g. frequencies) and qualitative (e.g. content and thematic analysis) methods.Discussion: Original research is urgently needed to design interventions to mitigate COVID-19 misinformation. The planned scoping review will help to address this gap.Systematic Review registrations: Systematic Review Registration: Open Science Framework (osf/io/etw9d).

Previous research indicated that corrective information can sometimes provoke a so-called “backfire effect” in which respondents more strongly endorsed a misperception about a controversial political or scientific issue when their beliefs or predispositions were challenged. I show how subsequent research and media coverage seized on this finding, distorting its generality and exaggerating its role relative to other factors in explaining the durability of political misperceptions. To the contrary, an emerging research consensus finds that corrective information is typically at least somewhat effective at increasing belief accuracy when received by respondents. However, the research that I review suggests that the accuracy-increasing effects of corrective information like fact checks often do not last or accumulate; instead, they frequently seem to decay or be overwhelmed by cues from elites and the media promoting more congenial but less accurate claims. As a result, misperceptions typically persist in public opinion for years after they have been debunked. Given these realities, the primary challenge for scientific communication is not to prevent backfire effects but instead, to understand how to target corrective information better and to make it more effective. Ultimately, however, the best approach is to disrupt the formation of linkages between group identities and false claims and to reduce the flow of cues reinforcing those claims from elites and the media. Doing so will require a shift from a strategy focused on providing information to the public to one that considers the roles of intermediaries in forming and maintaining belief systems.

A poisonous cocktail of othering, aversion, and moralization poses a threat to democracy

The effectiveness of vaccines in reducing child morbidity and mortality worldwide relies on public acceptance. However, relatively little is known about the effects of vaccine communication on vaccine attitudes and immunization behavior. Previous research suggests that common communication approaches may be ineffective or even counterproductive, especially among vaccine-hesitant parents. However, these studies typically rely on observational data or self-reported measures of vaccination intention. Using novel research designs, we tested the attitudinal and behavioral effects of messages encouraging vaccination in both a survey experiment conducted among a large sample of parents in Vermont who expressed hesitancy about childhood immunizations and a field experiment among parents whose children were overdue for vaccines. We find that neither a message promoting immunization as a social norm nor a message correcting common misperceptions about vaccines was measurably more effective than a standard public health message at improving parents’ attitudes toward vaccines, intention to vaccinate their children, or compliance with the recommended vaccine schedule. Our results highlight the need for more research on approaches to successfully reducing vaccine hesitancy among parents.

When a party or candidate loses the popular vote but still wins the election, do voters view the winner as legitimate? This scenario, known as an electoral inversion, describes the winners of two of the last six presidential elections in the United States. We report results from two experiments testing the effect of inversions on democratic legitimacy in the US context. Our results indicate that inversions significantly decrease the perceived legitimacy of winning candidates. Strikingly, this effect does not vary with the margin by which the winner loses the popular vote, nor by whether the candidate benefiting from the inversion is a co-partisan. The effect is driven by Democrats, who punish inversions regardless of candidate partisanship; few effects are observed among Republicans. These results suggest that the experience of inversions increases sensitivity to such outcomes among supporters of the losing party.

Newsfeed algorithms frequently amplify misinformation and other low-quality content. How can social media platforms more effectively promote reliable information? Existing approaches are difficult to scale and vulnerable to manipulation. In this paper, we propose using the political diversity of a website's audience as a quality signal. Using news source reliability ratings from domain experts and web browsing data from a diverse sample of 6,890 U.S. citizens, we first show that websites with more extreme and less politically diverse audiences have lower journalistic standards. We then incorporate audience diversity into a standard collaborative filtering framework and show that our improved algorithm increases the trustworthiness of websites suggested to users -- especially those who most frequently consume misinformation -- while keeping recommendations relevant. These findings suggest that partisan audience diversity is a valuable signal of higher journalistic standards that should be incorporated into algorithmic ranking decisions., Comment: 47 pages, 23 figures, 5 tables (including supplementary materials). Nat Hum Behav (2022)

Scholars and pundits fear that the American public���s commitment to democracy is declining and that citizens are willing to embrace candidates who would trample democratic principles. We examine whether violations of those principles generate resistance from voters and/or top campaign donors and whether such resistance extends across partisan lines. In a conjoint survey experiment, we investigate how regular Americans and donor elites trade off partisanship, policy positions, and support for democratic values when choosing between hypothetical political candidates. Our findings indicate that both citizens and donors punish candidates who endorse violations of democratic principles irrespective of the candidate���s party. However, partisans react very differently to candidates who support voter identification laws that threaten access to the franchise. This polarized response is especially strong among donors. These results suggest that the public and donors may sometimes be willing to forgive transgressions against democratic norms that align with their partisan and policy preferences.

Misperceptions and conspiracy theories about foreign powers and religious and ethnic groups can inflame intergroup conflict and distort public opinion, especially in divided and contentious regions...

Why do so many Americans hold misperceptions? We examine two factors that contribute to the prevalence of these beliefs. First, presenting correct information should reduce misperceptions, especially if provided in a clear and compelling format. We therefore test the effect of graphical information, which may be especially effective in facilitating belief updating about changes in quantities over time. In some cases, though, people may reject information because it threatens their worldview or self-concept – a mechanism that can be revealed by affirming individuals’ self-worth, which could make them more willing to acknowledge uncomfortable facts. We test both mechanisms jointly. In three experiments, we find that providing information in graphical form reduces misperceptions. A third study shows that this effect is greater than for equivalent textual information. Our findings for self-affirmation are more equivocal. We find limited evidence that self-affirmation can help diminish misperceptions when no other information is provided, but it does not consistently increase willingness to accept corrective information as previous research in social psychology would suggest. These results suggest that misperceptions are caused by a lack of information as well as psychological threat, but that these factors may interact in ways that are not yet well understood.

Significance Complex adaptive systems exhibit characteristic dynamics near tipping points such as critical slowing down (declining resilience to perturbations). We studied Twitter and Google search data about measles from California and the United States before and after the 2014–2015 Disneyland, California measles outbreak. We find critical slowing down starting a few years before the outbreak. However, population response to the outbreak causes resilience to increase afterward. A mathematical model of measles transmission and population vaccine sentiment predicts the same patterns. Crucially, critical slowing down begins long before a system actually reaches a tipping point. Thus, it may be possible to develop analytical tools to detect populations at heightened risk of a future episode of widespread vaccine refusal., Vaccine refusal can lead to renewed outbreaks of previously eliminated diseases and even delay global eradication. Vaccinating decisions exemplify a complex, coupled system where vaccinating behavior and disease dynamics influence one another. Such systems often exhibit critical phenomena—special dynamics close to a tipping point leading to a new dynamical regime. For instance, critical slowing down (declining rate of recovery from small perturbations) may emerge as a tipping point is approached. Here, we collected and geocoded tweets about measles–mumps–rubella vaccine and classified their sentiment using machine-learning algorithms. We also extracted data on measles-related Google searches. We find critical slowing down in the data at the level of California and the United States in the years before and after the 2014–2015 Disneyland, California measles outbreak. Critical slowing down starts growing appreciably several years before the Disneyland outbreak as vaccine uptake declines and the population approaches the tipping point. However, due to the adaptive nature of coupled behavior–disease systems, the population responds to the outbreak by moving away from the tipping point, causing “critical speeding up” whereby resilience to perturbations increases. A mathematical model of measles transmission and vaccine sentiment predicts the same qualitative patterns in the neighborhood of a tipping point to greatly reduced vaccine uptake and large epidemics. These results support the hypothesis that population vaccinating behavior near the disease elimination threshold is a critical phenomenon. Developing new analytical tools to detect these patterns in digital social data might help us identify populations at heightened risk of widespread vaccine refusal.

Standard accounts of legislative behavior typically neglect the activities of professional staff, who are treated as extensions of the elected officials they serve. However, staff appear to have substantial independent effects on observed levels of legislator productivity and policy preferences. In this article, we use a novel data set of comprehensive longitudinal employment records from the US House of Representatives to estimate the effects of congressional staff on legislative behavior. Specifically, results from a series of heteroskedastic Bayesian spatial autoregressive models indicate that members of Congress who exchange important staff members across congresses are more similar in their legislative effectiveness and voting patterns than we would otherwise expect. These findings suggest that scholars should reconsider the role of staff in the legislative process.

Political misperceptions can distort public debate and undermine people's ability to form meaningful opinions. Why do people often hold these false or unsupported beliefs, and why is it sometimes so difficult to convince them otherwise? We argue that political misperceptions are typically rooted in directionally motivated reasoning, which limits the effectiveness of corrective information about controversial issues and political figures. We discuss factors known to affect the prevalence of directionally motivated reasoning and assess strategies for accurately measuring misperceptions in surveys. Finally, we address the normative implications of misperceptions for democracy and suggest important topics for future research.

The widespread availability of voter files has improved the study of participation in American politics, but the lack of comprehensive data on nonregistrants creates difficult inferential issues. Most notably, observational studies that examine turnout rates among registrants often implicitly condition on registration, a posttreatment variable that can induce bias if the treatment of interest also affects the likelihood of registration. We introduce a sensitivity analysis to assess the potential bias induced by this problem, which we call differential registration bias. Our approach is most helpful for studies that estimate turnout among registrants using posttreatment registration data, but it is also valuable for studies that estimate turnout among the voting-eligible population using secondary sources. We illustrate our approach with two studies of voting eligibility effects on subsequent turnout among young voters. In both cases, eligibility appears to decrease turnout, but these effects are found to be highly sensitive to differential registration bias.

When political scandals erupt in the press, we usually blame misconduct by public officials, but these episodes are political events whose occurrence and severity also depend in part on the political and media context. Using data on U.S. governors, I show that several key factors affect the likelihood and intensity that alleged misconduct will be politicized by the opposition and publicized by the press. First, lower approval ratings, which decrease the cost of politicizing and publicizing an allegation, are generally associated with more frequent and intense media scandals. By contrast, competing news events can crowd potential scandals off the news agenda. However, no evidence is found that opposition control of state political institutions leads to more media scandal. These results suggest that the occurrence of media scandal depends more on circumstance than we typically assume.

Fake news emerged as an apparent global problem during the 2016 U.S. Presidential election. Addressing it requires a multidisciplinary effort to define the nature and extent of the problem, detect fake news in real time, and mitigate its potentially harmful effects. This will require a better understanding of how the Internet spreads content, how people process news, and how the two interact. We review the state of knowledge in these areas and discuss two broad potential mitigation strategies: better enabling individuals to identify fake news, and intervention within the platforms to reduce the attention given to fake news. The cooperation of Internet platforms (especially Facebook, Google, and Twitter) with researchers will be critical to understanding the scale of the issue and the effectiveness of possible interventions., This is the accepted version of the article, posted to comply with public access mandates. The final published version is available at https://doi.org/10.1126/science.aao2998

Context: Many observers believe that the policy response to the opioid crisis is less punitive than the crack scare and that the reason is that victims are (stereotypically) white.Methods: To assess this conjecture, we compile new longitudinal data on district-level drug-related deaths and (co)sponsorship of legislation on drug abuse in the House of Representatives over the past four decades. Using legislator fixed effects models, we then test how changes in drug-related death rates in legislators' districts predict changes in (co)sponsorship of treatment-oriented or punitive legislation in the subsequent year and assess whether these relationships vary by race of victim or drug type.Findings: Policy makers were more likely to introduce punitive drug-related bills during the crack scare and are more likely to introduce treatment-oriented bills during the current opioid crisis. The relationship between district-level drug deaths and subsequent sponsorship of treatment-oriented legislation is greater for opioid deaths than for cocaine-related deaths and for white victims than for black victims. By contrast, district-level drug deaths are not significantly related to sponsorship of punishment-oriented bills.Conclusions: These results suggest that the racial inequalities and double standards of drug policy still persist but in different forms.

Are citizens willing to accept journalistic fact-checks of misleading claims from candidates they support and to update their attitudes about those candidates? Previous studies have reached conflicting conclusions about the effects of exposure to counter-attitudinal information. As fact-checking has become more prominent, it is therefore worth examining how respondents respond to fact-checks of politicians—a question with important implications for understanding the effects of this journalistic format on elections. We present results to two experiments conducted during the 2016 campaign that test the effects of exposure to realistic journalistic fact-checks of claims made by Donald Trump during his convention speech and a general election debate. These messages improved the accuracy of respondents’ factual beliefs, even among his supporters, but had no measurable effect on attitudes toward Trump. These results suggest that journalistic fact-checks can reduce misperceptions but often have minimal effects on candidate evaluations or vote choice.

Why has fact-checking spread so quickly within U.S. political journalism? In the first field experiment conducted among reporters, we varied journalist exposure to messages that highlight either audience demand for fact-checking or the prestige it enjoys within the profession. Our results indicate that messages promoting the high status and journalistic values of fact-checking increased the prevalence of fact-checking coverage, while messages about audience demand were somewhat less successful. These findings suggest that political fact-checking is driven primarily by professional motives within journalism, a finding that helps us understand the process by which the practice spreads within the press as well as the factors that influence the behavior of journalists.

Conspiracy theories are prevalent among the public. Governments frequently release official documents attempting to explain events that inspire these beliefs. However, these documents are often heavily redacted, a practice that lay epistemic theory suggests might be interpreted as evidence for a conspiracy. To investigate this possibility, we tested the effect of redactions on beliefs in a well-known conspiracy theory. Results from two preregistered experiments indicate that conspiracy beliefs were higher when people were exposed to seemingly redacted documents compared to when they were exposed to unredacted documents that were otherwise identical. In addition, unredacted documents consistently lowered conspiracy beliefs relative to controls while redacted documents had reduced or null effects, suggesting that lay epistemic interpretations of the redactions undermined the effect of information in the documents. Our findings, which do not vary by conspiracy predispositions, suggest policymakers should be more transparent when releasing documents to refute misinformation.

Is American democracy under threat? The question is more prominent in political debate now than at any time in recent memory. However, it is also too blunt; there is widespread recognition that democracy is multifaceted and that backsliding, when it occurs, tends to be piecemeal. To address these concerns, we provide original data from surveys of political science experts and the public measuring the perceived importance and performance of U.S. democracy on a number of dimensions during the first year and a half of the Trump presidency. We draw on a theory of how politicians may transgress limits on their authority and the conditions under which constraints are self-enforcing. We connect this theory to our survey data in an effort to identify potential areas of agreement – bright lines – among experts and the public about the most important democratic principles and whether they have been violated. Public and expert perceptions often differ on the importance of specific democratic principles. In addition, though our experts perceive substantial democratic erosion, particularly in areas related to checks and balances, polarization between Trump supporters and opponents undermines any social consensus recognizing these violations.

The following report is intended to provide an overview of the current state of the literature on the relationship between social media; political polarization; and political “disinformation,” a term used to encompass a wide range of types of information about politics found online, including “fake news,” rumors, deliberately factually incorrect information, inadvertently factually incorrect information, politically slanted information, and “hyperpartisan” news. The review of the literature is provided in six separate sections, each of which can be read individually but that cumulatively are intended to provide an overview of what is known — and unknown — about the relationship between social media, political polarization, and disinformation. The report concludes by identifying key gaps in our understanding of these phenomena and the data that are needed to address them.

Many observers are concerned that campaign contributions could affect the decisions of elected judges. However, the empirical correlation between contributions and judicial decisions is consistent with two different explanations of judicial behavior: (a) money influences judges or (b) contributors choose to support candidates with a similar philosophical or legal perspective. In this article, we take advantage of North Carolina’s shift to a voluntary public finance system for state Supreme Court candidates to obtain more credible estimates of the contributions–behavior relationship. Applying a difference-in-differences research design, we provide evidence that justices who opted into public financing became relatively less favorable toward attorney donors. We also find partial support for our hypothesis that participating justices became more moderate in their voting patterns. Taken together, these findings suggest that public financing reduced responsiveness to donors among participating justices.

In this white paper, I propose a series of reforms intended to improve the rigor, timeliness, and replicability of published political science research. These changes could be proposed as part of the next solicitation for editors of the American Political Science Review or other disciplinary journals. If implemented, they would make our discipline a leader in publishing practices intended to minimize publication bias, encourage rapid and high-quality reviews, and maximize replicability and fairness to authors. In this way, they could help to enhance the quality and pace of the profession’s scholarly output and improve perceptions of its rigor both within and outside of academia over time, increasing trust in political science findings and building the credibility that is necessary for successful public engagement.

Are citizens willing to accept journalistic fact-checks of misleading claims from candidates they support and to update their attitudes about those candidates? Previous studies have reached conflicting conclusions about the effects of exposure to counter-attitudinal information. As fact-checking has become more prominent, it is therefore worth examining how respondents respond to fact-checks of politicians --- a question with important implications for understanding the effects of this journalistic format on elections. We present results to two experiments conducted during the 2016 campaign that test the effects of exposure to realistic journalistic fact-checks of claims made by Donald Trump during his convention speech and a general election debate. These messages improved the accuracy of respondents' factual beliefs, even among his supporters, but had no measurable effect on attitudes toward Trump. These results suggest that journalistic fact-checks can reduce misperceptions but often have minimal effects on candidate evaluations or vote choice.

Does external monitoring improve democratic performance? Fact-checking has come to play an increasingly important role in political coverage in the United States, but some research suggests it may be ineffective at reducing public misperceptions about controversial issues. However, fact-checking might instead help improve political discourse by increasing the reputational costs or risks of spreading misinformation for political elites. To evaluate this deterrent hypothesis, we conducted a field experiment on a diverse group of state legislators from nine U.S. states in the months before the November 2012 election. In the experiment, a randomly assigned subset of state legislators was sent a series of letters about the risks to their reputation and electoral security if they were caught making questionable statements. The legislators who were sent these letters were substantially less likely to receive a negative fact-checking rating or to have their accuracy questioned publicly, suggesting that fact-checking can reduce inaccuracy when it poses a salient threat.

OBJECTIVES: To test the effectiveness of messages designed to reduce vaccine misperceptions and increase vaccination rates for measles-mumps-rubella (MMR). METHODS: A Web-based nationally representative 2-wave survey experiment was conducted with 1759 parents age 18 years and older residing in the United States who have children in their household age 17 years or younger (conducted June–July 2011). Parents were randomly assigned to receive 1 of 4 interventions: (1) information explaining the lack of evidence that MMR causes autism from the Centers for Disease Control and Prevention; (2) textual information about the dangers of the diseases prevented by MMR from the Vaccine Information Statement; (3) images of children who have diseases prevented by the MMR vaccine; (4) a dramatic narrative about an infant who almost died of measles from a Centers for Disease Control and Prevention fact sheet; or to a control group. RESULTS: None of the interventions increased parental intent to vaccinate a future child. Refuting claims of an MMR/autism link successfully reduced misperceptions that vaccines cause autism but nonetheless decreased intent to vaccinate among parents who had the least favorable vaccine attitudes. In addition, images of sick children increased expressed belief in a vaccine/autism link and a dramatic narrative about an infant in danger increased self-reported belief in serious vaccine side effects. CONCLUSIONS: Current public health communications about vaccines may not be effective. For some parents, they may actually increase misperceptions or reduce vaccination intention. Attempts to increase concerns about communicable diseases or correct false claims about vaccines may be especially likely to be counterproductive. More study of pro-vaccine messaging is needed.

Despite its importance in contemporary American politics, presidential scandal is poorly understood within political science. Scholars typically interpret scandals as resulting from the disclosure of official misbehavior, but the likelihood and intensity of media scandals is also influenced by the political and news context. This article provides a theoretical argument for two independent factors that should increase the president's vulnerability to scandal: low approval among opposition party identifiers and a lack of congestion in the news agenda. Using new data and statistical approaches, I find strong support for both claims. These results suggest that contextual factors shape the occurrence of political events and how such events are interpreted.

Context Misperceptions are a major problem in debates about health care reform and other controversial health issues. Methods We conducted an experiment to determine if more aggressive media fact-checking could correct the false belief that the Affordable Care Act would create "death panels." Participants from an opt-in Internet panel were randomly assigned to either a control group in which they read an article on Sarah Palin's claims about "death panels" or an intervention group in which the article also contained corrective information refuting Palin. Findings The correction reduced belief in death panels and strong opposition to the reform bill among those who view Palin unfavorably and those who view her favorably but have low political knowledge. However, it backfired among politically knowledgeable Palin supporters, who were more likely to believe in death panels and to strongly oppose reform if they received the correction. Conclusions These results underscore the difficulty of reducing misperceptions about health care reform among individuals with the motivation and sophistication to reject corrective information.

Standard accounts of legislative behavior typically neglect the activities of professional staff, who are treated as extensions of the elected officials they serve. However, staff appear to have substantial independent effects on observed levels of legislator productivity and policy preferences. In this paper, we use a novel dataset of comprehensive longitudinal employment records from the U.S. House of Representatives to estimate the effects of Congressional staff on legislative behavior. Specifically, results from a series of heteroskedastic Bayesian spatial autoregressive models indicate that members of Congress who exchange important staff members across congresses are more similar in their legislative effectiveness and voting patterns than we would otherwise expect. These findings suggest that scholars should reconsider the role of staff in the legislative process.

Recent research has extended the belief-perseverance paradigm to the political realm, showing that negative information about political figures has a persistent effect on political opinions even after it has been discredited. However, little is known about the effects of false positive information about political figures. In three experiments, we find that discrediting positive information generates a “punishment effect” that is inconsistent with the previous literature on belief perseverance. We argue people attempt to adjust for the perceived influence of the false claim when the information is discredited. In this case, when trying to account for the effects of discredited positive information about a politician, people overestimate how much correction is needed and thus end up with a more negative opinion. (By contrast, people underestimate how much correction is needed to adjust for false negative information, leading to belief perseverance.) These results suggest that bogus credit claiming or other positive misinformation can have severe repercussions for politicians.

In Left Turn: How Liberal Bias Distorts The American Mind, Tim Groseclose argues that media effects play a crucial role in American politics. His case rests on three arguments: (1) that journalists tend overwhelmingly to be liberal rather than conservative; (2) that their innate political bias slants their views in empirically measurable ways; and (3) that this bias fundamentally shapes American politics, by bringing US citizens further to the left than they would naturally be. According to Groseclose, in a world where media bias did not exist, American citizens would on average hold views close to those of Ben Stein or Bill O'Reilly. In such a world, John McCain would have defeated Barack Obama by a popular vote margin of 56%—42% in the 2008 presidential election.In making these claims, Groseclose draws on his own research, and on recent media scholarship by both political scientists and economists, making the broader claim that peer-reviewed social science—which seeks to deal with problems such as endogeneity and selection bias—should be the starting point for public arguments about the role of the media. His book, then, is clearly an effort to bring social scientific arguments into mainstream debates. Groseclose makes no secret of his conservative political leanings—but recent books from left-leaning political scientists such as Jacob Hacker and Paul Pierson are equally unapologetic. It is at least plausible that political scientists' typical unwillingness to engage directly in political arguments has weakened the discipline's capacity for public engagement.In this symposium a diverse group of contributors have been invited to engage with Groseclose's arguments in ways that bring together specific empirical and/or theoretical points and arguments aimed at the broader “political science public sphere” that Perspectives on Politics seeks to nurture. Contributors were asked to consider these five questions: (1): How do we best measure media effects? (2): If media bias exists, what are its plausible sources? (3): Can one use work on media effects to determine what people's views would be in the absence of such bias? (4): Do you agree that American politics is insufficiently representative, and if so what do you consider the primary sources of this problem? (5): What kinds of political and/or media institutions or practices might enhance democratic discourse?—Henry Farrell, Associate Editor

We investigate the relationship between controversial roll call votes and support for Democratic incumbents in the 2010 midterm elections. Consistent with previous analyses, we find that supporters of health care reform paid a significant price at the polls. We go beyond these analyses by identifying a mechanism for this apparent effect: constituents perceived incumbents who supported health care reform as more ideologically distant (in this case, more liberal), which in turn was associated with lower support for those incumbents. Our analyses show that this perceived ideological difference mediates most of the apparent impact of support for health care reform on both individual-level vote choice and aggregate-level vote share. We conclude by simulating counterfactuals that suggest health care reform may have cost Democrats their House majority.