The face of illusory truth: Repetition of information elicits affective facial reactions predicting judgments of truth

People tend to judge repeated information as more likely true compared with new information. A key explanation for this phenomenon, called the illusory truth effect, is that repeated information can be processed more fluently, causing it to appear more familiar and trustworthy. To consider the function of time in investigating its underlying cognitive and affective mechanisms, our design comprised two retention intervals. Seventy-five participants rated the truth of new and repeated statements 10 min, as well as 1 week after first exposure while spontaneous facial expressions were assessed via electromyography. Our data demonstrate that repetition results not only in an increased probability of judging information as true (illusory truth effect) but also in specific facial reactions indicating increased positive affect, reduced mental effort, and increased familiarity (i.e., relaxations of musculus corrugator supercilii and frontalis) during the evaluation of information. The results moreover highlight the relevance of time: both the repetition-induced truth effect as well as EMG activities, indicating increased positive affect and reduced mental effort, decrease significantly after a longer interval.

The illusory certainty: Information repetition and impressions of truth enhance subjective confidence in validity judgments independently of the factual truth

People not only judge repeatedly perceived information as more likely being true (the so-called truth effect) they also tend to be more confident after judging the validity of repeated information. These phenomena are assumed to be caused by a higher subjective feeling of ease (i.e., fluency) when processing repeated (vs. new) information. Based on the suggestion that a higher number of coherent mental activations is promoting a fluency experience, we argue that besides repetition an already existing information network, that is (nonspecific) prior knowledge, can enhance fluency. Following this argumentation, information repetition as well as the act of judging incoming information as being true (vs. false) should feed into subjective confidence - independently of the factual truth (when judging under uncertainty). To test this, we reanalyzed two published data sets and conducted a new study. In total, participants (N = 247) gave 29,490 truth judgments and corresponding ratings of subjective confidence while attending two judgement phases (i.e., 10 min and 1 week after the exposure phase in each experiment). Results showed that (a) repetition (in 3 of 3 data sets) and (b) impressions of truth (in 2 of 3 data sets) were systematically related to higher subjective confidence. Moreover, we found (c) a significant positive interaction between repetition and impressions of truth after both intervals in all data sets. Our analyses further underline the moderating effect of time: Influences of repetition significantly decreased with increasing time interval. Notably, the factual truth did not systematically affect any of the above reported effects.

An ongoing secondary task can reduce the illusory truth effect

Introduction

People are more likely to believe repeated information-this is known as the Illusory Truth Effect (ITE). Recent research on the ITE has shown that semantic processing of statements plays a key role. In our day to day experience, we are often multi-tasking which can impact our ongoing processing of information around us. In three experiments, we investigate how asking participants to engage in an ongoing secondary task in the ITE paradigm influences the magnitude of the effect of repetition on belief.

Methods

Using an adapted ITE paradigm, we embedded a secondary task into each trial of the encoding and/or test phase (e.g., having participants count the number of vowels in a target word of each trivia claim) and calculated the overall accuracy on the task.

Results

We found that the overall ITE was larger when participants had no ongoing secondary task during the experiment. Further, we predicted and found that higher accuracy on the secondary task was associated with a larger ITE.

Discussion

These findings provide initial evidence that engaging in an ongoing secondary task may reduce the impact of repetition. Our findings suggest that exploring the impact of secondary tasks on the ITE is a fruitful area for further research.

The Effect of Repetition on the Perceived Truth of Tobacco-Related Health Misinformation Among U.S. Adults

As concerns about the effects of health misinformation rise, understanding why misbeliefs are accepted is increasingly important. People believe repeated statements more than novel statements, an effect known as truth by repetition, however this has not been examined in the context of tobacco information. Misbeliefs about tobacco are rampant and novel facts about tobacco are viewed as less believable. This paper examines how repetition of true and false tobacco statements affects truth perceptions. We recruited an online sample of 1,436 U.S. adults in May 2021. In an exposure phase, each participant rated their interest in 30 randomly selected statements about tobacco products and general knowledge trivia, half of them true and half false. The study had a two (tobacco product) by two (familiarity of statement claim) between-subjects design and a two (statement truth) by two (statement repetition) within-subjects design. During the testing phase participants rated the truthfulness of 24 repeated statements and 24 unseen statements. Repetition of true and false tobacco statements increased their subjective truth (diff=.20, p < .001), and the effect was larger for false claims compared to true claims. This underscores the importance of strategies to inoculate people against misinformation and calls for interventions that can stop the repetition of newly generated false claims.

Judging fast and slow: The truth effect does not increase under time-pressure conditions

Due to the information overload in today’s digital age, people may sometimes feel pressured to process and judge information especially fast. In three experiments, we examined whether time pressure increases the repetition-based truth effect — the tendency to judge repeatedly encountered statements more likely as “true” than novel statements. Based on the Heuristic-Systematic Model, a dual-process model in the field of persuasion research, we expected that time pressure would boost the truth effect by increasing reliance on processing fluency as a presumably heuristic cue for truth, and by decreasing knowledge retrieval as a presumably slow and systematic process that determines truth judgments. However, contrary to our expectation, time pressure did not moderate the truth effect. Importantly, this was the case for difficult statements, for which most people lack prior knowledge, as well as for easy statements, for which most people hold relevant knowledge. Overall, the findings clearly speak against the conception of fast, fluency-based truth judgments versus slow, knowledge-based truth judgments. In contrast, the results are compatible with a referential theory of the truth effect that does not distinguish between different types of truth judgments. Instead, it assumes that truth judgments rely on the coherence of localized networks in people’s semantic memory, formed by both repetition and prior knowledge.

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.

Easy on the mind, easy on the wrongdoer? No evidence for perceptual fluency effects on moral wrongness ratings

Processing fluency-the subjective ease of information processing-influences a variety of judgments (e.g., judgments of familiarity, liking, and truth). A study by Laham, Alter, and Goodwin (2009) suggests that this is also true for moral judgments. More specifically, the authors found that discrepant perceptual fluency mitigates moral wrongness ratings. In five studies (total N = 694), we tested the replicability of this finding for different kinds of scenarios (moral versus conventional transgressions) and different perceptual fluency manipulations. In Studies 1a and 1b we manipulated fluency by text background, in Studies 2a and 2b by font type, and in Study 3 by word spaces. Critically, none of the studies replicated Laham et al.'s discrepant fluency effect on moral wrongness ratings. In turn, we found that moral wrongness ratings were strongly affected by participants' emotional responses to the scenarios. Taken together, the findings of our five studies cast very strong doubt on perceptual fluency effects on moral judgments.

Truthiness, the illusory truth effect, and the role of need for cognition

Ease of processing-cognitive fluency-is a central input in assessments of truth, but little is known about individual differences in susceptibility to fluency-based biases in truth assessment. Focusing on two paradigms-truthiness and the illusory truth effect-we consider the role of Need for Cognition (NFC), an individual difference variable capturing one's preference for elaborative thought. Across five experiments, we replicated basic truthiness and illusory truth effects. We found very little evidence that NFC moderates truthiness. However, we found some evidence that (without an experimental warning), people high on NFC may be more susceptible to the illusory truth effect. This may reflect that elaborative thought increases the fluency with which encoded statements are processed after a delay (thus increasing the illusory truth effect). Future research may fruitfully test whether the influence of NFC and other individual difference measures depends on whether people are making immediate or delayed truth judgments.

Relative to what? Dynamic updating of fluency standards and between-participants illusions of truth

Previous research has shown that fluency effects are driven by discrepancies between current and baseline fluency. Thus, illusions of truth associated with repetition (which increases statement fluency and its perceived truth-value relative to new statements) are less likely to occur when participants judge pure lists of either all-repeated or all-new statements and comparisons are between-participants, than when participants judge mixed lists and comparisons are within-participants. Still, there are demonstrations of between-participants illusions of truth in the literature. In this manuscript, we explain the emergence of between-participants truth effects in terms of hypothetical dynamic updating of fluency standards. The findings of two experiments provide evidence for this hypothesis by showing that between-participants truth effects occur most strongly for the first elements of the statement list but are reduced over time. The findings suggest that the dynamics of fluency experiences contribute to the truth effect and should be taken into account when investigating illusions of truth.

Truth by Repetition: Explanations and Implications

People believe repeated information more than novel information; they show a repetition-induced truth effect. In a world of “alternative facts,” “fake news,” and strategic information management, understanding this effect is highly important. We first review explanations of the effect based on frequency, recognition, familiarity, and coherent references. On the basis of the latter explanation, we discuss the relations of these explanations. We then discuss implications of truth by repetition for the maintenance of false beliefs and ways to change potentially harmful false beliefs (e.g., “Vaccination causes autism”), illustrating that the truth-by-repetition phenomenon not only is of theoretical interest but also has immediate practical relevance.