During health crises, misinformation may spread rapidly on social media, leading to hesitancy towards health authorities. The COVID-19 pandemic prompted significant research on how communication from health authorities can effectively facilitate compliance with health-related behavioral advice such as distancing and vaccination. Far fewer studies have assessed whether and how public health communication can help citizens avoid the harmful consequences of exposure to COVID-19 misinformation, including passing it on to others. In two experiments in Denmark during the pandemic, the effectiveness of a 3-minute and a 15-second intervention from the Danish Health Authorities on social media was assessed, along with an accuracy nudge. The findings showed that the 3-minute intervention providing competences through concrete and actionable advice decreased sharing of COVID-19-related misinformation and boosted their sense of self-efficacy. These findings suggest that authorities can effectively invest in building citizens’ competences in order to mitigate the spread of misinformation on social media.

Scholars of International Organizations (IOs) increasingly use elite surveys to study the preferences and decisions of policymakers. When designing these surveys, one central concern is low statistical power, because respondents are typically recruited from a small and inaccessible population. However, much of what we know about how to incentivize elites to participate in surveys is based on anecdotal reflections, rather than systematic evidence on which incentives work best. In this article, we study the efficacy of three incentives in a preregistered experiment with World Bank staff. These incentives were the chance to win an Amazon voucher, a donation made to a relevant charity, and a promise to provide a detailed report on the findings. We find that no incentive outperformed the control group, and the monetary incentive decreased the number of respondents on average by one-third compared to the control group (from around 8% to around 5%).

How do citizens react to repeated losses in politics? This paper argues that experiencing accumulated losses creates strong incentives to externalize responsibility for these losses to the decision-making procedure, which can, in turn, erode legitimacy perceptions among the public. Using a survey experiment (N = 2,146) simulating accumulated losses in a series of direct votes among Irish citizens, we find that decision acceptance and the perceived legitimacy of the decision-making procedure diminish with every loss. Three accumulated losses depress the perceived legitimacy of the political system. These effects are mediated by procedural fairness perceptions, suggesting that even when democratic procedures are used, accumulated losses can induce a belief that the process and system are rigged.

A long line of research has established that Americans who subscribe to Christian nationalism have a preference for those inside their group and animosity toward those outside their group. These beliefs may impede the equal application of the rule of law, a link that has been suggested but not formally tested. Utilizing experimental data from a survey conducted in fall 2021, we assess the equal application of the rule of law for in and outgroup members conditional on Christian nationalism and belief in Christian persecution. We suggest that ingroup love may move distinctly from outgroup hate. Our results suggest that Christian nationalists have a preference for the ingroup, but do not automatically denigrate outgroups. However, belief in Christian persecution drives animosity toward outgroups, while not elevating the ingroup. Christian nationalist outgroup hatred must be triggered by threat, which has been the project of movement and party elites.

How was Chinese people’s confidence in the political system linked to their perception of Covid infection risk, perception of health threat of Covid infection, lockdown experience, and attitudes toward the dynamic Zero-Covid policy? Using 2 waves of online surveys conducted in 2020 and 2022, we investigated how these factors were related. Individuals who were more supportive of the Zero-Covid policy were more confident. Those who were less supportive of the Zero-Covid policy were from areas with more severe Covid infections and experienced a longer lockdown as well; these individuals also perceived higher Covid infection risk and health threat. As such, their confidence in the political system was also more likely to drop from 2020 to 2022. In sum, these findings suggest that Chinese people’s confidence in the political system was linked to their Covid infection risk perception, perceived Covid threat to health, lockdown experience, and attitudes toward the Zero-Covid policy. These findings were corroborated with the severity of Covid infections in the province and individual’s political beliefs and orientation.

Former president Trump made hundreds of candidate endorsements in the 2022 Republican primaries. The state of Georgia garnered outsized attention because it was ground zero for Trump’s false accusations of a stolen 2020 presidential election. Trump endorsed several candidates in Georgia’s May 2022 GOP primary contests, including candidates challenging Governor Brian Kemp and Secretary of State Brad Raffensperger, incumbents drawing Trump’s ire for upholding the 2020 outcome favoring Joe Biden. In a survey of likely Georgia GOP primary voters randomizing whether they are told which candidate Trump endorsed in five statewide races (governor, US Senate, lieutenant governor, secretary of state, and insurance commissioner), our analysis shows substantial variability in the influence of Trump’s endorsement. With scant prior information in low-profile contests (e.g., insurance commissioner), the Trump endorsement has a substantial impact, whereas it is rendered ineffectual in the most high-profile race for governor. Thus, the findings demonstrate the remarkable variability of a Trump endorsement, which is primarily contingent upon the salience of a specific race.

Paranoia is common in clinical and nonclinical populations, consistent with continuum models of psychosis. A number of experimental studies have been conducted that attempt to induce, manipulate or measure paranoid thinking in both clinical and nonclinical populations, which is important to understand causal mechanisms and advance psychological interventions. Our aim was to conduct a systematic review and meta-analysis of experimental studies (non-sleep, non-drug paradigms) on psychometrically assessed paranoia in clinical and nonclinical populations. The review was conducted using PRISMA guidelines. Six databases (PsycINFO, PubMed, EMBASE, Web of Science, Medline and AMED) were searched for peer-reviewed experimental studies using within and between-subject designs to investigate paranoia in clinical and nonclinical populations. Effect sizes for each study were calculated using Hedge's g and were integrated using a random effect meta-analysis model. Thirty studies were included in the review (total n = 3898), which used 13 experimental paradigms to induce paranoia; 10 studies set out to explicitly induce paranoia, and 20 studies induced a range of other states. Effect sizes for individual studies ranged from 0.03 to 1.55. Meta-analysis found a significant summary effect of 0.51 [95% confidence interval 0.37–0.66, p < 0.001], indicating a medium effect of experimental paradigms on paranoia. Paranoia can be induced and investigated using a wide range of experimental paradigms, which can inform decision-making about which paradigms to use in future studies, and is consistent with cognitive, continuum and evolutionary models of paranoia.

As in other sciences, an economic experiment is an artificial situation created by a researcher for the purpose of answering one or more scientific questions. Experiments of various types are used in economics to understand the causes of poverty and how it might be alleviated. The methods can identify causal relationships between variables and thereby isolate factors that can lead to poverty as well as to document the behavioral consequences of poverty. Experiments can also be used to provide test beds for proposed policies to alleviate poverty. This essay describes a variety of ways in which experiments have been employed to understand and combat poverty. A line of laboratory experiments that considers which economic institutions are conducive to economic growth is discussed in detail. The results show that decentralized markets are conducive to allowing an economy to operate as efficiently as it can. However, in an economy with a theoretical “poverty trap,” the market works more efficiently if accompanied by a democratic voting process and freedom of communication.

Nudges are widely employed tools within organizations, but they are often criticized for harming autonomy and for being ineffective. We assess these two criticisms simultaneously: can nudges be both autonomy-preserving and effective in changing behavior? We developed three nudges – an opinion leader nudge, a rule-of-thumb and self-nudges – to reduce a particularly sticky behavior: email use. In a survey experiment of 4,112 healthcare employees, we tested their effect on perceived autonomy and subjective effectiveness. We also tested traditional policy instruments for comparison. Next, to assess objective effectiveness, we conducted a quasi-field experiment in a large healthcare organization with an estimate of 1,189 active email users. We found that each nudge in isolation, but especially when combined, was perceived to be both autonomy-preserving and effective, and more so than traditional policy instruments like an access limit or a monetary reward. We also found some evidence that the combination of all nudges decreased actual email use. This paper advances the literature by showing how innovations in nudge design improve nudges’ ability to be autonomy-preserving and effective.

Despite the widespread assumption of terrorism's “terrifying” effect, there has been little systematic testing of the specific emotional microfoundations underlying public opinion about terrorism. While fear is one well-recognized emotional response to terror threats, in societies where terrorism is rare, anger may play a more pivotal role, with distinct consequences for citizens’ downstream political attitudes. To test the impact of these emotional mechanisms on public opinion in the wake of terrorism, I employ a multi-arm mechanism experiment (n = 5,499) in the United States that manipulates both exposure to news about different types of terror attacks and the encouraged emotional response. I supplement this experimental study with observational analyses of the emotional content of social media posts in the wake of sixteen real-world terror attacks in the United States. I find that not only is anger the dominant emotional response to terrorism across both studies, but also that punitive motivations and support for retaliation are both directly shaped by experimentally induced anger after exposure to news about terrorism. These findings illuminate strategic incentives shaping militants’ use of terror tactics, electoral constraints leaders face in formulating counterterror policy, and the emotional mechanisms fueling cycles of political violence.

Communities inhabiting the arid and semi-arid areas of eastern Africa have long suffered from and engaged in pastoral conflicts. However, since some countries in the region became oil producers, the conditions affecting pastoral conflicts have changed. This study examines how oil extraction may influence pastoral conflicts by using a survey experiment conducted in Turkana County, Kenya, on a sample of 801 respondents. The study finds that overall, respondents’ perceived risks of pastoral conflicts decrease when they are primed about the consequences of oil extraction leading to fundamental changes in pastoral livelihoods, such as an increase in employment opportunities in the oil sector and rapid social changes. The residents of Turkana view pastoral conflicts as customary as long as pastoralism continues and fundamental changes to pastoralism-based livelihoods originating from oil discovery and extraction may lead to a decrease in the pastoralist population engaging in pastoral conflicts.

Paul-Louis Simond’s 1898 experiment demonstrating fleas as the vector of plague is today recognised as one of the breakthrough moments in modern epidemiology, as it established the insect-borne transmission of plague. Providing the first exhaustive examination of primary sources from the Institut Pasteur’s 1897–98 ‘India Mission’, including Simond’s notebooks, experiment carnets and correspondence, and cross-examining this material with colonial medical sources from the first years of the third plague pandemic in British India, the article demonstrates that Simond’s engagement with the question of the propagation of plague was much more complex and ambiguous than the teleological story reproduced in established historical works suggests. On the one hand, the article reveals that the famous 1898 experiment was botched, and that Simond’s misreported its ambiguous findings for the Annales de l’Institut Pasteur. On the other hand, the article shows that, in the course of his ‘India Mission’, Simond framed rats as involved in the propagation of plague irreducibly in their relation to other potential sources of infection and not simply in terms of a parasitological mechanism. The article illuminates Simond’s complex epidemiological reasoning about plague transmission, situating it within its proper colonial and epistemological context, and argues for a new historical gaze on the rat as an ‘epidemiological dividual’, which highlights the relational and contingent nature of epidemiological framings of the animal during the third plague pandemic.

Populist radical right parties (PRRPs) claim to be particularly responsive to people’s needs and have been identified as a major source of disinformation. The present contribution sets up a field experiment to zoom in on one-to-one communication between voters and their parliamentarians. By drawing on pieces of misinformation that are present among different parties’ supporters, artificial citizen’s requests are sent to all 2503 German federal parliamentarians. In fact, PRRP politicians do not turn out to be more responsive and they are by far more reluctant to reject misinformation. In contrast, parliamentarians of all other parties largely object to misinformation, even if it matches their political positions and is shared by their electorates. In opposition to PRRP politicians who reveal signs of vote-seeking behaviour, established parties’ communication behaviour indicates a high degree of intrinsic motivation.

In an experimental gift-exchange game, we explore the transformative capacity of vulnerable trust, which we define as trusting untrustworthy players when their untrustworthiness is common knowledge between co-players. In our experiment, there are two treatments: the “Information” treatment and the “No-Information” treatment in which we respectively disclose or not information about trustees’ trustworthiness. Our laboratory evidence consistently supports the transformative capacity of trustors’ vulnerable trust, which generates higher transfers, more trustworthiness and increased reciprocity by untrustworthy trustees.