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8.1 Beyond Fact-Checking: Tackling the Infodemic

The global pandemic saw a rapid rise in information regarding COVID-19 (Frenkel et al. 2020; Tardáguila 2020; Zarocostas 2020), prompting the World Health Organization (WHO) to declare an infodemic (WHO Director General 2020): a situation where there exists too much information, both offline and online, that can make it difficult to identify trustworthy information and which causes confusion (Pertwee et al. 2022). Misinformation is a dangerous part of the infodemic and can contain outright false messaging, which is easier to spot or fact-check but also uses techniques of manipulation to contort information, make it appear true, and much more difficult to identify (Roozenbeek and van der Linden 2019a). Determining a definition of misinformation has proved to be a scholarly challenge, with some defining misinformation as information presented by fictitious or fake sources (Pennycook et al. 2021), while others categorise misinformation according to whether or not it contains misleading information that distorts the truth, regardless of the source (Traberg 2022). Here we define misinformation in line with the latter characterisation of the term.

Misinformation in and of itself is not inherently dangerous if nobody believes it. If everyone simply scrolled past it and gave it no attention, the problem would be much easier to contain. However, misinformation during the pandemic has been associated with a decrease in compliance with public health guidelines (Freeman et al. 2022; Imhoff and Lamberty 2020; Roozenbeek et al. 2020a), and an increase in violent behaviour (Featherstone and Zhang 2020; Jolley and Paterson 2020). Although the COVID-19 vaccine has the potential to end the pandemic, the simultaneous infodemic has led to people questioning the safety of vaccines, thereby lowering vaccination intentions (Loomba et al. 2021) and uptake (Pierri et al. 2022). Misinformation has also given rise to dangerous health-related beliefs such as the promotion of bleach as a cure for the virus (Litman et al. 2020) and conspiracy theories suggesting the purposeful manufacturing of the virus as a bioweapon (Roozenbeek et al. 2020a).

To tackle the infodemic, a focus has, therefore, been to understand how we can prevent people from being persuaded to believe misinformation, leading to the design and testing of interventions to counter the influence of misinformation. Amongst other initiatives, fact-checks have become increasingly popular – these have included either removing information that is flagged as false (Taylor 2021) or providing disclaimers on articles (RAND 2022). Although studies have found positive effects of fact-checks (Porter and Wood 2021; Walter et al. 2020), debunking is not always fully effective, as misinformation can continue to influence how we see the world even if we have been told that it is false: a psychological effect known as the ‘continued influence effect’ (Lewandowsky et al. 2012; Cook et al. 2017). For example, picture a social media user scrolling past a clip posted by a Facebook friend, which is initially perceived as true. Later, the same person notices that the clip now contains a correction noting that it contained false information. This correction may not be internalised into memory and the individual may not update their beliefs, leaving the correction ineffective (Ecker et al. 2022). Indeed, as more time passes between the initial exposure to a message, the more likely it is that the source is forgotten and the message increases in persuasiveness over time, known as ‘the sleeper effect’ (Kumkale and Albarracín 2004). A final problem with fact-checking is that it does not pierce echo-chambers, which exist when groups of polarised social media users aggregate around different types of content, as users in these online communities can respond to fact-checks negatively (Zollo et al. 2017).

Likening the infodemic to its biological pandemic counterpart, the cost of treatment dwarfs the cost of prevention. Although the infodemic analogy has not gone without critique (Simon and Camargo 2021), researchers have successfully used models from epidemiology to understand the spread of misinformation in social networks (Vosoughi et al. 2018; Cinelli et al. 2021; Jin et al. 2013). According to social scientists, the answer to the infodemic might mirror the answer to the pandemic – that is, through psychologically inoculating (i.e. vaccinating) individuals before exposure to the misinformation ‘disease’. In this chapter, we detail how a psychological theory from the 1960s has been applied to tackling online misinformation, and highlight projects that have demonstrated that gamified ‘vaccines’ against misinformation can have inoculating effects on people (Traberg et al., 2022), making them more resistant to manipulation.

8.2 Inoculation Theory: A Vaccine Against Persuasion

While the idea of a vaccine against persuasion techniques dates back to the 1960s, it is only in the last decade that this approach has been applied to tackling misinformation. Based on inoculation theory, psychological inoculations or ‘prebunks’ were originally proposed and tested by McGuire (1964) to train individuals to resist having their attitudes changed by persuasive messages (e.g. propaganda). His suggestion was that the psychological process involved in creating resistance against persuasion is comparable to our bodies creating biological resistance against viruses (McGuire 1961). As with biological vaccines where individuals are injected with a weakened version of a virus to generate immunity against future exposure to viral pathogens, psychological vaccines involve exposing individuals to ‘weak’ persuasive ‘attacks’ such as watered-down bite-sized versions of misleading arguments followed by a strong and persuasive rebuttal to these weak arguments.

When the body encounters a biological vaccine, the immune system responds by generating antibodies. With psychological vaccines, when the individual is pre-emptively exposed to a ‘weak’ persuasive attack followed by a strong rebuttal, mental ‘antibodies’ are generated as the individual is given the tools to spot deception. According to inoculation theory, this takes place through the use of two key mechanisms that must be present in the inoculation process, known as ‘threat’ or ‘forewarning’ and refutational preemption (prebunking). Threat entails warning people that they will be exposed to a manipulative message, motivating the ‘mental’ immune system into action. The second element, refutational preemption or prebunking provides individuals with the means to shoot down these misleading arguments. The idea is that once inoculated, individuals are better prepared to resist ‘stronger’ misleading arguments in the future.

While initial experiments showed that after ‘inoculation’, individuals were better at resisting persuasive attacks, the theory was never tested in the context of misinformation and remained largely untouched until recently. The threat posed by misinformation online (and more recently, the infodemic) gave rise to new potential applications of psychological vaccines (for recent reviews of the theory, see Traberg 2022; Lewandowsky and van der Linden 2021; Compton et al. 2021). Scientists thus found a potential new virus to inoculate people against dangerous and misleading information on the internet.

Inoculation was initially designed to be prophylactic; meaning it was intended to protect against future persuasive attacks before they occurred (McGuire 1964). However, in the context of infodemics, it may be more appropriate to discuss therapeutic inoculation as misinformation reaches more people and spreads at faster rates than fact-checked content (Vosoughi et al. 2018), implying that a large proportion of any inoculation will occur after exposure. Today, following the advancement of therapeutic vaccines that can still boost immune responses when someone has already been infected (e.g. HPV), ‘therapeutic’ inoculation also occurs in a psychological sense when individuals are inoculated after being exposed to, but not yet fully convinced by, misinformation (Compton et al. 2021). The distinction between prebunking and debunking (post-hoc corrections) likely depends on the incubation period of the misinformation virus in question; that is, sometimes, it may only take a single exposure to dupe someone on social media, but at other times, it may require repeated exposure from trusted members in one’s social network over extended periods of time (van der Linden 2023).

8.2.1 Initial Vaccines Against Specific Misinformation

One of the early pioneering studies looked at the prevalence of misinformation about climate change (van der Linden et al. 2017), as previous research had not focused on contentious issues or misinformation (Banas and Rains 2010). To test whether being inoculated against climate misinformation would reduce the likelihood of persuasion, the researchers recruited over 2000 participants online who were assigned to groups containing either inoculation messages or simple facts. The scientists attempted to ‘vaccinate’ individuals psychologically against the Oregon Petition – a real-life petition denying anthropogenic climate change claimed to have been signed by 31,000 ‘scientists’. This petition has been debunked (Greenberg 2017) – with fewer than 1% of the ‘scientists’ on the list having any degree or expertise in climate science, with names like Dr. Gari Halliwell (from the Spice Girls) cited. Participants in the inoculation condition were forewarned that someone would try to persuade them that climate change is a hoax (threat element) (van der Linden et al. 2017). The study also provided factual information about the fact that 97% of climate scientists agree that humans have contributed to the global rise in temperatures and proof that the petition consists of the names of fake experts (refutational pre-emption).

Results showed that while the misinformation message negatively impacted people’s beliefs about climate change, it mostly only persuaded participants who had not been inoculated beforehand. In other words, the inoculation messages successfully protected individuals against the misinformation. Consequently, one of the first modern applications of inoculation theory showed that it was possible to protect individuals against future exposure to misinformation, and these results were soon replicated across several additional studies (Cook et al. 2017; Williams and Bond 2020).

8.2.2 A Broad-Spectrum Vaccine Through Gamification

In the initial studies, the goal was to protect individuals from being persuaded by specific myths (e.g. claims of climate change being a hoax). However, due to the volume of misinformation covering a wide range of topics, inoculating against specific myths limits its scalability. As such, inoculation interventions were developed to educate individuals on the techniques used by peddlers of misinformation. Specifically, researchers developed entertaining and interactive games built on principles of inoculation theory in a new and accessible way. Firstly, the game environments allow players to be exposed to the threat posed by fake news as they witness the ‘ease’ with which truths can be spun into falsehoods using misleading tactics, representing the ‘threat’ element of inoculation. Secondly, in the games, players are taught how and why fake news producers use misleading techniques. Exposing players to these misleading tactics in a humorous way is intended to inspire players to come up with counter-arguments, representing the ‘refutational pre-emption’. These games are known as technique-based inoculation interventions, as they train participants to spot the misleading tactics used across a wide range of misinformation messages, rather than focusing on a specific example of misinformation. In addition, game-based inoculation is also superior to text-based interventions in that they provide higher entertainment value and are publicly available.

One of the most well-known and thoroughly tested inoculation games is the award-winning Bad News game developed by Roozenbeek and van der Linden (2019a, b) in collaboration with the Dutch media platform DROG (DROG 2019). In Bad News, players are placed in the shoes of a misinformation producer and tasked with spreading weakened doses of their own misinformation within a simulated social media platform. Players are taught how to use six commonly used fake news tactics: (1) impersonating individuals or groups to make audiences believe the source of the information is credible; (2) polarising audiences by feeding on the divide between political groups; (3) using overly emotive language that distorts the original news to spark strong emotional reactions; (4) creating or inspiring conspiracy theories to explain recent events; (5) trolling users, famous people, or organisations, for example, to create the impression that a larger group agree or disagree with a claim; and (6) discrediting otherwise credible individuals, institutions, or well-established facts to create doubt amongst audiences.

This type of inoculation is also otherwise known as active inoculation as players are not directly told why the misinformation is misleading (instead known as passive inoculation), but they learn it through actively having to create it themselves in a controlled setting. The original authors of inoculation theory (McGuire and Papageorgis 1962) believed that this type of inoculation may be more effective, because participants are more involved, which may lead to them remembering it better – that is learning by doing (Tyler et al. 1979). A screenshot of these gamified interventions is provided in Fig. 8.1.

Fig. 8.1
A photograph of three games. The game name at the top center reads a. BAD NEWS with keywords strike, break, ignore, conceal, and destroy. b. Breaking HARMONY SQUARE below with a play button. c. GO VIRAL with some text below and a start button in the center.

Bad News, Harmony Square, and Go Viral! games. (Source: Bad News [www.getbadnews.com], Harmony Square [www.harmonysquare.game], and Go Viral! [www.goviralgame.com]. Reprinted with permission)

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8.2.3 Testing the Efficacy of Inoculation Games

To assess whether such interventions are successful, that is, if they effectively reduce the likelihood of news consumers being persuaded to believe fake news, scientists have tested the game using several different scenarios. First, the game was tested in a live card version (Roozenbeek and van der Linden 2019a). After promising results, the online version of the game was released and has been widely studied since its inception. The impact of the online Bad News game was originally tested in a before-after design, meaning the researchers test the players’ improvement in spotting fake news after the game compared to before (Roozenbeek and van der Linden 2019a; Roozenbeek et al. 2021; Maertens et al. 2021; Basol et al. 2020). In one of the largest studies, Roozenbeek and van der Linden (2019a) recruited 15,000 online participants whose abilities to spot misleading news headlines were evaluated. Results showed that players evaluated misinformation headlines as significantly less reliable following gameplay, highlighting the ‘inoculating’ effects of the Bad News game. For example, after having been ‘vaccinated’ against conspiracy theories, game players would judge conspiratorial headlines such as ‘Scientists discovered greenhouse effect years ago but aren’t allowed to publish it, report claims’ as less reliable after playing, compared to before.

Although conspiracy narratives represent just one of six misinformation techniques in the game, they remain a highly effective tool to spread misinformation. Conspiracy theories can be used to vilify certain groups by accusing them of secretly plotting to achieve their own evil goals (Nera et al. 2022) while simultaneously placing the conspiracy believer in a morally superior victim role (Douglas et al. 2017, 2019). The believability of conspiracy theories can be explained by their perceived ability to satisfy unmet psychological needs (Douglas et al. 2017, 2019; Biddlestone et al. 2022), and the entertainment value they can provide (van Prooijen et al. 2022). Given their complexity, conspiracy theories have been given increased attention from social scientists and prior to the creation of inoculation games, it remained unclear whether inoculation interventions could successfully reduce the likelihood of believing conspiracy theories. Promisingly, Roozenbeek and van der Linden (2019a) showed that the Bad News game could be used to protect individuals against conspiratorial narratives.

8.3 Criticisms of the Initial Game Studies

8.3.1 The Use of Randomised Research Designs

One concern about testing the effectiveness of games by measuring improvements using before and after measures is that it remains uncertain whether the improvement is the result of the specific intervention. This concern can be alleviated by testing the intervention using randomised research trials by (1) allocating a control condition and (2) changing the test items (the false headlines) in the game. Basol et al. (2020) therefore allocated participants to a control group that played Tetris, showing that participants who played the Bad News game outperformed their Tetris-playing counterparts when it came to spotting unreliable headlines – with even stronger effects than prior studies. The team found that the intervention also improved participants’ confidence in their own abilities to spot misinformation: a promising finding as higher confidence can boost one’s ability to resist persuasion (Tormala and Petty 2004). Other studies have shown that even when headlines are changed in the post-test, participants’ abilities to spot previously unseen misinformation are improved through the Bad News inoculation game (Roozenbeek et al. 2021, 2022a).

8.3.2 Long-Term Effectiveness of Inoculation

Recently, researchers have begun to study the long-term effectiveness of psychological inoculation with results showing that inoculation interventions are at least as good as, and sometimes better than, other traditional interventions in providing long-term protection against misinformation (Banas and Rains 2010; Maertens et al. 2021; Nisa et al. 2019). Effects typically last for at least a couple of weeks (Maertens et al. 2020; Maertens 2022), and sometimes for months (Pfau et al. 1992; Pfau et al. 2006; Maertens et al. 2021). However, research also shows that the inoculation effect starts decaying within days after the intervention, meaning that a diminishing effect needs to be accounted for (Maertens 2022). Recent research using the Bad News game indicates that the inoculation effect can last up to 2 months but needs to be ‘boosted’ in a similar way that biomedical vaccine booster shots may help to prolong immunity against viruses. Practically, this means regularly engaging people with a fun quiz or shortened version of the initial treatment to boost both people’s ability and motivation to resist fake news (Maertens et al. 2021; Maertens 2022).

8.4 Applications and Herd Iimmunity

8.4.1 Policy Applications of Inoculation Theory

One of the major advantages of inoculation interventions is that they can be applied in other settings. For instance, Cranky Uncle is a humour-based inoculation game about climate misinformation (Cook 2021). In a recent study, Cook et al. (2022) showed that playing the game improved students’ ability to identify logical fallacies often used in climate misinformation. Other games have been developed in collaboration with government partners, such as Go Viral! (https://www.goviralgame.com/), a 5-minute game about COVID-19 misinformation produced in collaboration with the UK Cabinet Office (Basol et al. 2021), and Harmony Square (https://www.harmonysquare.game/), a game developed with the US Department of Homeland Security, which tackles political disinformation and polarisation (Roozenbeek and van der Linden 2020). These games have been tested (Basol et al. 2021) and translated into numerous languages (Bad News, Go Viral! and Harmony Square include the option to select a different language). Both Basol et al. (2021) and Roozenbeek et al. (2020b) found that the games were similarly effective across different (European) languages, and that people are better able to spot misinformation online and are less likely to report wanting to share it with their social networks.

The games are freely accessible online and can be used as part of public health campaigns. For example, GoViral! was part of WHO’s ‘Stop the Spread’ campaign and the United Nation’s ‘Verified’ campaign, reaching over 200 million impressions on social media (Government Communication Service 2021; WHO 2021). Another practical application of inoculation interventions is to run ad campaigns on social media platforms. Roozenbeek et al. (2022b) showed that running a video ad campaign on YouTube using inoculation videos they had created significantly improved YouTube users’ ability to identify manipulative content correctly ‘in the wild’ on YouTube, at a cost of a maximum of US$ 0.05 per video view. Policymakers may, thus, run similar campaigns on YouTube or other social media platforms using these or other inoculation videos.

8.4.2 Can Inoculation Spread?

One limitation of vaccines against misinformation is that, much like vaccines against biological infections, it is difficult, if not impossible, to inoculate everyone. However, what if this was not necessary? In the past, research had suggested that once individuals had been psychologically inoculated, talking with others about the inoculation might, in turn, actually increase their own resistance to misinformation (Compton and Pfau 2009; Ivanov et al. 2012). Exciting novel research by Basol (2022) suggests that inoculated individuals voluntarily engage in post-inoculation talk without instruction, and that not only does talking about inoculation increase the protective effects of inoculation for the inoculated individual, inoculated individuals can vicariously inoculate the recipients of talk. In another study, participants were more willing to share the GoViral! game with their friends and family than other interventions. If enough people share the inoculation in their network, it could outpace the spread of misinformation, or at least protect enough people within a social network so that the influence of misinformation is substantially reduced as recent computer simulations have indicated (Pilditch et al. 2022). In this way, inoculation has the potential to promote psychological herd-immunity against misinformation, as inoculating one individual could end up having exponential effects.

8.5 Conclusion

In this chapter, we have outlined the history of inoculation theory and its applications to tackling misinformation. Given the increasing number of studies that highlight the efficacy of psychological vaccines in reducing persuasion by misinformation, it is clear that inoculation interventions represent a promising and potentially scalable tool to limit the influence of online misinformation.

Like all interventions, however, they are not without limitations and unresolved questions remain. For example, news and information online is not consumed in a social vacuum. Instead, news consumption increasingly takes place in a social environment where social cues are present. Furthermore, individuals hold pre-existing beliefs about the world and may be prone to additional cognitive biases that impact their perceptions and judgements of information veracity (Traberg and van der Linden 2022). As such, there may be other factors at play other than the simple news headline when it comes to being persuaded by misinformation, which have yet to be tested in relation to inoculation interventions. Unlike biological vaccines, psychological vaccines against misinformation cannot claim to guarantee 90% efficacy against future misinformation attacks. However, given the rapid spread of misinformation and the lack of alternative scalable solutions, inoculation intervention remains one of the most powerful tools currently available.