Validity judgments of rumors heard multiple times: the shape of the truth effect

Prominent misinformation interventions reduce misperceptions but increase scepticism

Current interventions to combat misinformation, including fact-checking, media literacy tips and media coverage of misinformation, may have unintended consequences for democracy. We propose that these interventions may increase scepticism towards all information, including accurate information. Across three online survey experiments in three diverse countries (the United States, Poland and Hong Kong; total n = 6,127), we tested the negative spillover effects of existing strategies and compared them with three alternative interventions against misinformation. We examined how exposure to fact-checking, media literacy tips and media coverage of misinformation affects individuals' perception of both factual and false information, as well as their trust in key democratic institutions. Our results show that while all interventions successfully reduce belief in false information, they also negatively impact the credibility of factual information. This highlights the need for further improved strategies that minimize the harms and maximize the benefits of interventions against misinformation.

More familiar, more credible? Distinguishing two types of familiarity on the truth effect using the drift-diffusion model

Familiar information is more likely to be accepted as true. This illusory truth effect has a tremendous negative impact on misinformation intervention. Previous studies focused on the familiarity from repeated exposure in the laboratory, ignoring preexisting familiarity with real-world misinformation. Over three studies (total N = 337), we investigated the cognitive mechanisms behind the truth biases from these two familiarity sources, and whether fact-checking can curb such biased truth perceptions. Studies 1 and 2 found robust truth effects induced by two sources of familiarity but with different cognitive processes. According to the cognitive process model, repetition-induced familiarity reduced decision prudence. Preexisting familiarity instead enhanced truth-congruent evidence accumulation. Study 3 showed that pre-exposing statements with warning flags eliminated the bias to truth induced by repetition but not that from preexisting familiarity. These repeated statements with warning labels also reduced decision caution. These findings furthered the understanding of how different sources of familiarity affect truth perceptions and undermine the intervention through different cognitive processes.

The illusory truth effect: A review of how repetition increases belief in misinformation

Repetition increases belief in information, a phenomenon known as the illusory truth effect. In laboratory experiments, the illusory truth effect has often been examined using general trivia statements as stimuli, but repetition also increases belief in misinformation, such as fake news headlines and conspiracy beliefs. Repetition even increases belief in claims that are implausible or that contradict prior knowledge. Repetition also has broader impacts beyond belief, such as increasing sharing intentions of news headlines and decreasing how unethical an act is perceived to be. Although the illusory truth effect is robust, some interventions reduce its magnitude, including instruction to focus on accuracy and awareness of the illusory truth effect. These strategies may be effective for reducing belief in misinformation.

Does Foreign-Accented Speech Affect Credibility? Evidence from the Illusory-Truth Paradigm

In a pioneering study, Lev-Ari and Keysar (2010) observed that unknown statements are judged less credible when uttered with foreign accent compared to native accent. This finding was interpreted in terms of processing fluency; when intelligibility is reduced, the credibility of the message decreases. Here, we use the illusory truth paradigm to explore how accent affects credibility. In a between-participant design, participants were exposed to unknown statements uttered by native-accented or foreign-accented speakers. After a distractor task, the same statements were presented with new statements, and participants assessed their truthfulness. Truthfulness ratings were higher for repeated statements than for new statements, replicating the illusory truth effect. Contrary to the processing fluency hypothesis, the effect was similar in both the foreign-accented and native-accented speech groups. A new group of participants rated the speakers' voices on various social traits. A negative bias against foreign speakers was observed. However, this negative-bias did not affect truth ratings.The impact of foreign-accented speech on message credibility is discussed in the context of two factors, processing fluency and out-group stereotype activation.

People underestimate the influence of repetition on truth judgments (and more so for themselves than for others)

People judge repeated statements as more truthful than new statements: a truth effect. In three pre-registered experiments (N = 463), we examined whether people expect repetition to influence truth judgments more for others than for themselves: a bias blind spot in the truth effect. In Experiments 1 and 2, using moderately plausible and implausible statements, respectively, the test for the bias blind spot did not pass the significance threshold set for a two-step sequential analysis. Experiment 3 considered moderately plausible statements but with a larger sample of participants. Additionally, it compared actual performance after a two-day delay with participants' predictions for themselves and others. This time, we found clear evidence for a bias blind spot in the truth effect. Experiment 3 also showed that participants underestimated the magnitude of the truth effect, especially so for themselves, and that predictions and actual truth effect scores were not significantly related. Finally, an integrative analysis focusing on a more conservative between-participant approach found clear frequentist and Bayesian evidence for a bias blind spot. Overall, the results indicate that people (1) hold beliefs about the effect of repetition on truth judgments, (2) believe that this effect is larger for others than for themselves, (3) and underestimate the effect's magnitude, and (4) particularly so for themselves.

The Role of Deliberative Cognitive Styles in Preventing Belief in Politicized COVID-19 Misinformation

Misinformation related to COVID-19 is a threat to public health. The present study examined the potential for deliberative cognitive styles such as actively open-minded thinking and need for evidence in deterring belief in misinformation and promoting belief in true information related to COVID-19. In addition, regarding how responses to the pandemic have been politicized, the role of political orientation and motivated reasoning were also examined. We conducted a survey in South Korea (N = 1466) during May 2020. Participants answered measures related to demographics, open-minded thinking, need for evidence, and accuracy perceptions of COVID-19 misinformation and true information items. Multi-level analyses of the survey data found that while motivated reasoning was present, deliberative cognitive styles (actively open-minded thinking and need for evidence) decreased belief in misinformation without intensifying motivated reasoning tendencies. Findings also showed a political asymmetry where conservatives detected COVID-19 misinformation at a lesser rate. Overall, results suggest that health communication related to COVID-19 misinformation should pay attention to conservative populations. Results also imply that interventions that activate deliberative cognitive styles hold promise in reducing belief in COVID-19 misinformation.

Repetition could increase the perceived truth of conspiracy theories

Conspiracy theories can be encountered repeatedly, which raises the issue of the effect of their repeated exposure on beliefs. Earlier studies found that repetition increases truth judgments of factual statements, whether they are uncertain, highly implausible, or fake news, for instance. Would this "truth effect" be observed with conspiracy statements? If so, is the effect size smaller than the typical truth effect, and is it associated with individual differences such as cognitive style and conspiracy mentality? In the present preregistered study, we addressed these three issues. We asked participants to provide binary truth judgments to conspiracy and factual statements already displayed in an exposure phase (an interest judgment task) or that were new (displayed only in the truth judgment task). We measured participants' cognitive style with the three-item Cognitive Reflection Test (CRT), and conspiracy mentality with the Conspiracy Mentality Questionnaire (CMQ). Importantly, we found that repetition increased truth judgments of conspiracy theories, unmoderated by cognitive style and conspiracy mentality. Additionally, we found that the truth effect was smaller with conspiracy theories than with uncertain factual statements, and suggest explanations for this difference. The results suggest that repetition may be a simple way to increase belief in conspiracy theories. Whether repetition increases conspiracy beliefs in natural settings and how it contributes to conspiracism compared to other factors are important questions for future research.

The evasive truth: do mere exposures at the subliminal and supraliminal levels drive the illusory truth effect?

The subjective truth of a statement is boosted by mere exposure to itself or a part of itself. This phenomenon is referred to as the illusory truth effect. We examined whether subliminal pre-exposure to the statement topic would increase its subjective truth. In the exposure phase, participants observed the topic, which was presented supraliminally or subliminally. After the exposure phase, they rated the subjective truth of the statement. If unconscious processing contributed to the illusory truth effect, subliminal exposure to the topic would increase the subjective truth of the statement. On the other hand, if the illusory truth effect required conscious and controlled processing, increases in the subjective truth of a statement would be induced only by supraliminal exposure to the topic. The results showed that the illusory truth effect was not found in either supraliminal or subliminal groups. Our findings provide no reliable evidence that pre-exposure to the statement topic saliently promotes its subjective truth.

The impact of COVID-19 misinformation and trust in institutions on preventive behaviors

Misinformation related to coronavirus disease 2019 (COVID-19) has the potential to suppress preventive behaviors that mitigate the spread of COVID-19. Early research on the behavioral consequences of COVID-19 misinformation is mixed, and most rely on cross-sectional data. We examined whether believing in COVID-19 misinformation at one time point influences engaging in preventive behaviors later. In addition, we investigated the role of trust in institutions. We conducted a two-wave survey in South Korea and examined the association between belief in COVID-19 misinformation at Wave 1 and preventive behaviors at Wave 2 controlling for preventive behaviors at Wave 1. We also analyzed whether there is an interaction between belief in COVID-19 misinformation and trust in institutions. Belief in COVID-19 misinformation at Wave 1 significantly increased avoidance of preventive behaviors at Wave 2, but after accounting for trust in institutions, this effect disappeared. Rather, trust in institutions significantly decreased avoidance of preventive behaviors. In addition, misinformation increased avoidance of preventive behaviors among those who trusted institutions the most. Results suggest that building trust in institutions is essential in promoting COVID-19 preventive behaviors. Belief in COVID-19 misinformation may have harmful effects, but these effects were pronounced for those who highly trust institutions.

Is Earth a perfect square? Repetition increases the perceived truth of highly implausible statements

A single exposure to statements is typically enough to increase their perceived truth. This Truth-by-Repetition (TBR) effect has long been assumed to occur only with statements whose truth value is unknown to participants. Contrary to this hypothesis, recent research has found that statements contradicting participants' prior knowledge (as established from a first sample of participants) show a TBR effect following their repetition (in a second, independent sample of participants). As for now, however, attempts at finding a TBR effect for blatantly false (i.e., highly implausible) statements have failed. Here, we reasoned that highly implausible statements such as Elephants run faster than cheetahs may show repetition effects, provided a sensitive truth measure is used and statements are repeated more than just once. In a preregistered experiment, participants judged on a 100-point scale the truth of highly implausible statements that were either new to them or had been presented five times before judgment. We observed an effect of repetition: repeated statements were judged more true than new ones, although all judgments were judged below the scale midpoint. Exploratory analyses additionally show that about half the participants showed no or even a reversed effect of repetition. The results provide the first empirical evidence that repetition can increase perceived truth even for highly implausible statements, although not equally so for all participants and not to the point of making the statements look true.

Getting to the source of the illusion of consensus

Consensus between informants is a valuable cue to a claim's epistemic value, when informants' beliefs are developed independently of each other. Recent work (Yousif et al., 2019) described an illusion of consensus such that people did not generally discriminate between the epistemic warrant of true consensus, where a majority claim is supported by multiple independent sources, and false consensus arising from repetition of a single source's claim. Four experiments tested a novel account of the illusion of consensus; that it arises when people are unsure about the independence of the primary sources on which informant claims are based. When this independence relationship was ambiguous we found evidence for the illusion. However, when steps were taken to highlight the independence between data sources in the true consensus conditions, and confidence in a claim was measured against a no consensus baseline (where there was an equal number of reports supporting and opposing a claim), more weight was given to claims based on true consensus than false consensus. These findings show that although the illusion of consensus is prevalent, people do have the capacity to distinguish between true and false consensus.

Debunking health myths on the internet: the persuasive effect of (visual) online communication

Aim

Developing evidence-based recommendations on how to debunk health-related misinformation and more specific health myths in (online) communication is important for individual health and the society. The present study investigated the effects of debunking/correction texts created according to the latest research findings with regard to four different health myths on recipients’ belief, behaviour and feelings regarding the myths. Further, the study investigated the effects of different visualisations (machine-technical created image, diagram, image of an expert, message without an image) in the debunking texts.

Subject and methods

A representative sample of German Internet users (N = 700) participated in an anonymous online survey experiment with a 4 (myths) × 4 (picture) mixed study design.

Results

The results show that receiving an online news article that refutes a widespread health myth with or without the use of an image can significantly change the attitudes of the recipients toward this myth. The most influential variable was the attributed credibility: the more credible a debunking text is for a recipient, the more corrective effectiveness it has. However, the corrective messages did not differ in their persuasive effects depending on the image types used.

Conclusion

The results offer an optimistic outlook on the correction of health-related misinformation and especially health myths and insight into why and how people change their beliefs (or not) and how beliefs in health myths can be reduced. The findings can be used by journalists, scientists, doctors and many other actors for efficient (online) communication.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10389-022-01694-3.

Correction format has a limited role when debunking misinformation

Given that being misinformed can have negative ramifications, finding optimal corrective techniques has become a key focus of research. In recent years, several divergent correction formats have been proposed as superior based on distinct theoretical frameworks. However, these correction formats have not been compared in controlled settings, so the suggested superiority of each format remains speculative. Across four experiments, the current paper investigated how altering the format of corrections influences people's subsequent reliance on misinformation. We examined whether myth-first, fact-first, fact-only, or myth-only correction formats were most effective, using a range of different materials and participant pools. Experiments 1 and 2 focused on climate change misconceptions; participants were Qualtrics online panel members and students taking part in a massive open online course, respectively. Experiments 3 and 4 used misconceptions from a diverse set of topics, with Amazon Mechanical Turk crowdworkers and university student participants. We found that the impact of a correction on beliefs and inferential reasoning was largely independent of the specific format used. The clearest evidence for any potential relative superiority emerged in Experiment 4, which found that the myth-first format was more effective at myth correction than the fact-first format after a delayed retention interval. However, in general it appeared that as long as the key ingredients of a correction were presented, format did not make a considerable difference. This suggests that simply providing corrective information, regardless of format, is far more important than how the correction is presented.

The effects of repeating false and misleading information on belief

False and misleading information is readily accessible in people's environments, oftentimes reaching people repeatedly. This repeated exposure can significantly affect people's beliefs about the world, as has been noted by scholars in political science, communication, and cognitive, developmental, and social psychology. In particular, repetition increases belief in false information, even when the misinformation contradicts prior knowledge. We review work across these disciplines, identifying factors that may heighten, diminish, or have no impact on these adverse effects of repetition on belief. Specifically, we organize our discussion around variations in what information is repeated, to whom the information is repeated, how people interact with this repetition, and how people's beliefs are measured. A key cross-disciplinary theme is that the most influential factor is how carefully or critically people process the false information. However, several open questions remain when comparing findings across different fields and approaches. We conclude by noting a need for more interdisciplinary work to help resolve these questions, as well as a need for more work in naturalistic settings so that we can better understand and combat the effects of repeated circulation of false and misleading information in society. This article is categorized under: Psychology > Memory Psychology > Reasoning and Decision Making.

The effects of repetition frequency on the illusory truth effect

Repeated information is often perceived as more truthful than new information. This finding is known as the illusory truth effect, and it is typically thought to occur because repetition increases processing fluency. Because fluency and truth are frequently correlated in the real world, people learn to use processing fluency as a marker for truthfulness. Although the illusory truth effect is a robust phenomenon, almost all studies examining it have used three or fewer repetitions. To address this limitation, we conducted two experiments using a larger number of repetitions. In Experiment 1, we showed participants trivia statements up to 9 times and in Experiment 2 statements were shown up to 27 times. Later, participants rated the truthfulness of the previously seen statements and of new statements. In both experiments, we found that perceived truthfulness increased as the number of repetitions increased. However, these truth rating increases were logarithmic in shape. The largest increase in perceived truth came from encountering a statement for the second time, and beyond this were incrementally smaller increases in perceived truth for each additional repetition. These findings add to our theoretical understanding of the illusory truth effect and have applications for advertising, politics, and the propagation of "fake news."

Is it all about the feeling? Affective and (meta-)cognitive mechanisms underlying the truth effect

People are more likely to judge repeatedly perceived statements as true. A decisive explanation for this so-called truth effect is that the repeated information can be processed more fluently than new information and that this fluency experience renders the information more familiar and trustworthy. Little is known, however, regarding whether and how affective states and dispositional cognitive preferences influence the truth effect. To this end, we conducted two experiments in which we manipulated (a) processing fluency via repetition, (b) the time interval (10 min vs. 1 week) between repetitions, and (c) short-term affective states using the presentation of emotional faces (Experiment 1) or the presence of an irrelevant source for changes in affective states (Experiment 2). Additionally, we assessed the dispositional variables need for cognitive closure (NCC), preference for deliberation (PD) and preference for intuition (PI). Results of Experiment 1 showed that the truth effect was significantly reduced for statements that were followed by a negative prime, although this was the case only for the longer repetition lag. Furthermore, higher NCC and lower PD scores were associated with an increased truth effect. Results of Experiment 2 replicated the moderating role of NCC and further showed that participants, who were provided with an alternative source for changes in their affective states, showed a reduced truth effect. Together, the findings suggest that (a) fluency-related changes in affective states may be (co-)responsible for the truth effect, (b) the truth effect is decreased when the repetition interval is long rather than short, and (c) the truth effect is increased for individuals with a higher need for cognitive closure. Theoretical implications of these findings are discussed.

Not just conspiracy theories: Vaccine opponents and proponents add to the COVID-19 'infodemic' on Twitter

In February 2020, the World Health Organization announced an 'infodemic' -- a deluge of both accurate and inaccurate health information -- that accompanied the global pandemic of COVID-19 as a major challenge to effective health communication. We assessed content from the most active vaccine accounts on Twitter to understand how existing online communities contributed to the 'infodemic' during the early stages of the pandemic. While we expected vaccine opponents to share misleading information about COVID-19, we also found vaccine proponents were not immune to spreading less reliable claims. In both groups, the single largest topic of discussion consisted of narratives comparing COVID-19 to other diseases like seasonal influenza, often downplaying the severity of the novel coronavirus. When considering the scope of the 'infodemic,' researchers and health communicators must move beyond focusing on known bad actors and the most egregious types of misinformation to scrutinize the full spectrum of information -- from both reliable and unreliable sources -- that the public is likely to encounter online.

Judging Truth

Deceptive claims surround us, embedded in fake news, advertisements, political propaganda, and rumors. How do people know what to believe? Truth judgments reflect inferences drawn from three types of information: base rates, feelings, and consistency with information retrieved from memory. First, people exhibit a bias to accept incoming information, because most claims in our environments are true. Second, people interpret feelings, like ease of processing, as evidence of truth. And third, people can (but do not always) consider whether assertions match facts and source information stored in memory. This three-part framework predicts specific illusions (e.g., truthiness, illusory truth), offers ways to correct stubborn misconceptions, and suggests the importance of converging cues in a post-truth world, where falsehoods travel further and faster than the truth.

Social media's contribution to political misperceptions in U.S. Presidential elections

There is considerable concern about the role that social media, such as Facebook and Twitter, play in promoting misperceptions during political campaigns. These technologies are widely used, and inaccurate information flowing across them has a high profile. This research uses three-wave panel surveys conducted with representative samples of Americans during both the 2012 and 2016 U.S. Presidential elections to assess whether use of social media for political information promoted endorsement of falsehoods about major party candidates or important campaign issues. Fixed effects regression helps ensure that observed effects are not due to individual differences. Results indicate that social media use had a small but significant influence on misperceptions about President Obama in the 2012 election, and that this effect was most pronounced among strong partisans. Social media had no effect on belief accuracy about the Republican candidate in that election. The 2016 survey focused on campaign issues. There is no evidence that social media use influenced belief accuracy about these topics in aggregate, but Facebook users were unique. Social media use by this group reduced issue misperceptions relative to those who only used other social media. These results demonstrate that social media can alter citizens' willingness to endorse falsehoods during an election, but that the effects are often small.

Rumor Acceptance during Public Health Crises: Testing the Emotional Congruence Hypothesis

Rumors pose a significant challenge to officials combatting a public health crisis. The flow of unsubstantiated and often inaccurate information can dilute the effects of more accurate messaging. Understanding why rumors thrive in this context is a crucial first step to constraining them. We propose a novel mechanism for explaining rumor acceptance during a health crisis, arguing that the congruence between one's emotional state and the emotion induced by a rumor leads people to believe the rumor. Data collected using a novel experimental design provide preliminary evidence for our emotional congruence hypothesis. Participants who felt angry were more likely to accept anger-inducing rumors than those who were not angry. We discuss the implications of this insight for public health officials combatting rumors during a health crisis.