Misinformation has been a pressing issue since the beginning of the COVID-19 pandemic, threatening our ability to effectively act on the crisis. Nevertheless, little is known about the actual effects of fake news on behavioural intentions. Does exposure to or belief in misinformation about COVID-19 vaccines affect people’s intentions to receive such a vaccine? This paper attempts to address this question via three preregistered experiments (N = 3463). In Study 1, participants (n = 1269) were exposed to fabricated pro- or anti-vaccine information or to neutral true information, and then asked about their intentions to get vaccinated. In Study 2, participants (n = 646) were exposed to true pro- and anti-vaccine information, while Study 3 (n = 1548) experimentally manipulated beliefs in novel misinformation about COVID-19 vaccines by increasing exposure to the information. The results of these three studies showed that exposure to false information about the vaccines had little effect on participants’ intentions to get vaccinated, even when multiple exposures led them to believe the headlines to be more accurate. An exploratory meta-analysis of studies 1 and 3, with a combined sample size of 2683, showed that exposure to false information both supporting and opposing COVID-19 vaccines actually increased vaccination intentions, though the effect size was very small. We conclude by cautioning researchers against equating exposure to misinformation or perceived accuracy of false news with actual behaviours.

Abstract. Misinformation can have noxious impacts on cognition, fostering the formation of false beliefs, retroactively distorting memory for events, and influencing reasoning and decision-making even after it has been credibly corrected. Researchers investigating the impacts of real-world misinformation are therefore faced with an ethical issue: they must consider the immediate and long-term consequences of exposing participants to false claims. In this paper, we first present an overview of the ethical risks associated with real-world misinformation. We then report results from a scoping review of ethical practices in misinformation research. We investigated (1) the extent to which researchers report the details of their ethical practices, including issues of informed consent and debriefing, and (2) the specific steps that researchers report taking to protect participants from the consequences of misinformation exposure. We found that fewer than 30% of misinformation papers report any debriefing, and almost no authors assessed the effectiveness of their debriefing procedure. Building on the findings from this review, we evaluate the balance of risk versus reward currently operating in this field and propose a set of guidelines for best practices. Our ultimate goal is to allow researchers the freedom to investigate questions of considerable scientific and societal impact while meeting their ethical obligations to participants.

Misinformation continually threatens efforts to control the COVID‐19 pandemic, with vaccine misinformation now a key concern. False memories for misinformation can influence behavioural intentions, yet little is known about the factors affecting (false) memories for vaccine‐related news items. Across two experiments (total n = 1481), this paper explores the effects of pre‐existing vaccine opinions on reported memories for true and false news items. In Study 1, participants ( n = 817) were exposed to fabricated pro‐ or anti‐vaccine news items, and then asked if they have a memory of this news event having occurred. In Study 2, participants ( n = 646) viewed true pro‐ or anti‐vaccine news items. News items were more likely to be remembered when they aligned with participants' pre‐existing vaccine beliefs, with stronger effects for pro‐vaccine information. We conclude by encouraging researchers to consider the role of attitudinal bias when developing interventions to reduce susceptibility to misinformation.

Misinformation has been a pressing issue since the beginning of COVID-19 pandemic, threatening our ability to effectively act on the crisis. More recently, the availability of vaccines in developed countries has not always translated into high vaccination rates, with online misinformation often presented as the culprit. Yet little is known about the actual effects of fake news on behavioural intentions. Does exposure to misinformation about COVID-19 vaccines indeed affects people’s intentions to receive such a vaccine? This paper attempts to answer this question through three preregistered experiments (N=3463). In Study 1, participants (n=1269) were exposed to fabricated pro- or anti-vaccine information or to neutral true information, and then asked about their intentions to get vaccinated, alongside a few other behavioural intentions. In Study 2, participants (n=1863) were exposed to true pro- and anti-vaccine information, while Study 3 (n=1548) compared the effects of single and multiple exposures to novel misinformation about COVID-19 vaccines. The results showed that exposure to false information on the vaccines did not affect the participants’ intentions to get vaccinated, even when multiple exposures led them to believe that the headlines were more accurate than in the single exposure conditions. An exploratory meta-analysis of studies 1 and 3 (n=2683) showed that exposure to false information about COVID-19 vaccines, regardless of whether it was in favour of or against vaccines, increased vaccination intentions. We conclude by cautioning researchers against equating exposure to misinformation or perceived accuracy of false news with actual behaviours.

Misinformation can have noxious impacts on cognition, fostering formation of false beliefs, retroactively distorting memory for events, and influencing reasoning and decision making even after it has been credibly corrected. Researchers investigating the impacts of real-world misinformation are therefore faced with an ethical issue: they must consider the immediate and longer-term consequences of exposing participants to false claims. In this paper, we first present an overview of the ethical risks associated with real-world misinformation. We then report results from a scoping review of ethical practices in misinformation research. We investigated (1) the extent to which researchers report the details of their ethical practices, including issues of informed consent and debriefing, and (2) the specific steps that researchers report taking to protect participants from the consequences of misinformation exposure. We found that fewer than 30% of misinformation papers report any debriefing at all, and almost no authors assessed the effectiveness of their debriefing procedure. Building on the findings from this review, we evaluate the balance of risk versus reward currently operating in this field, and propose a set of guidelines for best practice. Our ultimate goal is to allow researchers the freedom to investigate questions of considerable scientific and societal impact, while meeting their ethical obligations to participants.