misinformation (Pierre 2020), bullshit (van Prooijen et al. 2018), distrust of scientists and authority (Rutjens et al. 2018), extremism (Imhoff et al. 2022b), and paranormal belief (Darwin et al. 2011), and all these types of belief have been linked to, or even studied interchangeably with, conspiracy belief. What, therefore, makes conspiracy theories special in this crowded field of strange and unhelpful beliefs? Are the effects we have observed specific to conspiracy theories, or even true of conspiracy theories, if we control for their overlap with related kinds of belief? In order to answer these questions, we need a theory of what exactly conspiracy theories are—what makes them ontologically different from other beliefs. We also need a theory of what they do—what makes them functionally different from other beliefs, and why. We need these theories to be underpinned by research in which scales of conspiracy belief are designed and validated against theoretically informed measurement models, and in which the study of conspiracy belief compares, contrasts, and adjusts for related varieties of belief that lack some of the defining features of conspiracy theories. None of these are offered by the literature so far.
These contributions will be necessary, but not sufficient, to fulfill what may be the central mission of research on conspiracy theories—to understand and address their role in contemporary societal developments, from declining faith in democracy to political polarization to widespread vaccine refusal (Douglas et al. 2019). If conspiracy theories are contributing to these problems, it must be that they are disseminated, adopted, and affect attitudes and behavior en masse. Thus, a comprehensive theory of the societal impact of conspiracy beliefs must account for their antecedents, their consequences, and their transmission. At present, psychological scientists have focused on one of these facets at a time, or occasionally two (Douglas et al. 2017, Liekefett et al. 2021).
An obstacle to integrating these lines of research and theory into the causes, consequences, and transmission of conspiracy beliefs is not just that they have developed separately from each other. As is often remarked (e.g., Lyons et al. 2019, Swami et al. 2016), each line of research has also tended to be rather piecemeal. A number of low-level theoretical models have been developed, and studies have examined a limited number of variables each time. The newer lines of research on the consequences and transmission of conspiracy theories share the limitation that, on the whole, theories that connect existing research findings are lacking. As a result, many relevant antecedent, consequent, and contextual variables have been uncovered at different levels of analysis without much integration. A conceptual scheme is needed to organize variables within, as well as across, these different lines of research.
A related issue has hampered progress in conspiracy theory research. This is the difficulty of recruiting research participants who are strong believers in conspiracy theories. These are the people the public may have in mind when they think about conspiracy theorists and whom researchers may have had in mind when they describe populations who have a closed, obsessive mindset and who do not participate in mainstream civic, political, or health systems (Goertzel 1994, Sunstein & Vermeule 2009). These participants are difficult to access in part because they are perhaps less numerous than suggested by the rhetoric and media buzz that often surrounds academic papers (Sutton & Douglas 2022). Further, these people can be distrustful of conspiracy theory research and therefore reluctant to take part in it. Recent evidence suggests that belief in conspiracy theories is not distributed normally and that strong believers in conspiracy theories comprise a cluster of people who might be different from the rest of the population (Imhoff et al. 2022a). This can lead to mismatches in the evidence base and the aspirations of theoretical ideas about conspiracy belief—they want to explain social ills arising from extreme or entrenched beliefs but are tested on participants whose attitudes to conspiracy theories range from dismissive to moderate sympathy (Franks et al. 2017, Sutton & Douglas 2014). Recently, more survey and interview studies are succeeding in recruiting participants who are more prone to strong forms of conspiracy belief (e.g., Franks et al. 2017, Harambam & Aupers 2017). Observational studies are also increasingly
