Despite the known dangers of smoking and the common desire to quit (Babb et al., 2017) millions of Americans continue to smoke cigarettes (Cornelius et al., 2020), demonstrating the need for additional interventions. Noncombustible nicotine products expose users to fewer and/or lower levels of harmful constituents (U.S. Department of Health and Human Services, 2010, Nutt et al., 2014, Stratton et al., 2018), and may have lower disease risk compared to combustible cigarettes (Broadstock, 2007, McNeill et al., 2018, Oh and Kacker, 2014). Alternatively, very low nicotine products, such as very low nicotine cigarettes (VLNC), might reduce dependence and aid cessation (Hatsukami et al., 2010, Donny et al., 2015). In 2019, FDA started authorizing such products to use modified risk or modified exposure marketing claims if manufacturers demonstrated a benefit to population health (i.e., modified risk tobacco products (MRTPs) (U.S. Food and Administration, 2022).

A potential barrier to uptake of lower-risk noncombustible products among adults who smoke is inaccurate relative harm perceptions about these products. A large proportion of adults who smoke have inaccurate relative harm perceptions when comparing a variety of tobacco products (Denlinger-Apte et al., 2021, Morgan and Cappella, 2021, Czoli et al., 2017, Kiviniemi and Kozlowski, 2015). For example, data from the 2022 Health Information National Trends Survey recently found that only around 10 % of adults who smoke perceived e-cigarettes as less harmful than cigarettes (National Cancer Institute). VLNC are also poorly understood by the public. Nearly 50 % of adults who smoked in one study reported that they believed VLNC are less likely to cause disease compared to regular cigarettes when they are smoked the same way (O’Brien et al., 2017, Byron et al., 2018). These misperceptions might be associated with low perceived benefit of noncombustible MRTPs and low willingness to switch (Morgan and Cappella, 2021) or longer-term use of VLNC that cause the same diseases as cigarettes (Chen et al., 2008).

Misperceptions about what characteristics of tobacco products significantly increase disease risk may contribute to these inaccurate relative harm perceptions. Incorrectly believing nicotine is a major cause of cancer, for instance, might support faulty inferential reasoning that all products with nicotine are equally harmful and likely to cause cancer, making it a potentially important belief to target for correction. Similar reasoning may explain why some people think that products with very low levels of nicotine, like VLNC, are less harmful than cigarettes. These potentially problematic misperceptions about nicotine are prevalent. An estimated 60 % of adults who smoke inaccurately believe that nicotine causes cancer (Weiger et al., 2022).

In experimental settings, it has been demonstrated that messaging can correct misperceptions about nicotine and improve the accuracy of relative harm perceptions. One multi-country experiment that exposed adults who smoke to a multipage factsheet explaining why smokeless products are less harmful than combustible products and how nicotine is responsible for addiction but not disease risk, observed improvements in knowledge about what causes disease risk from smoking, although this finding was not significant in the US sample (Borland et al., 2012). Videos from experts that e-cigarettes are less harmful (Svenson et al., 2021) and brief, infographic-type messages about switching to e-cigarettes to reduce risk of disease or exposure to chemicals (Yang et al., 2019) similarly reduced misperceptions about the relative risk of e-cigarettes and increased use intentions. Brief messaging (Villanti et al., 2019) and factsheets (Yang et al., 2019) highlighting that nicotine is not a cause of cancer were also able to reduce nicotine misperceptions and improve relative harm perception accuracy. Although all of these studies found significant improvements in perception accuracy, misperception remained common among study participants despite exposure to corrective information (Borland et al., 2012, Svenson et al., 2021, Yang et al., 2019, Villanti et al., 2019, Yang et al., 2019). These findings indicate that additional strategies might be needed to correct both misperceptions about nicotine and inferential beliefs about relative harm.

Corrective messaging has been the topic of significant research. Exposure to corrective information has frequently elicited correct recall of the corrective information, however, misinformation is often still used to make inferences about related topics, which has come to be known as the Continued Influence Effect (CIE) in the psychological and communication literature (Ecker et al., 2011, Johnson and Seifert, 1994, Lewandowsky et al., 2012). It has been theorized that, when presented with corrective messaging, individuals may engage in ‘surface updating’ (i.e., the individual retains the corrected information specifically addressed in the message), but fail to engage in ‘global updating’ (fully integrating information into beliefs so it can be applied via inferential reasoning and behavioral decisions) (Johnson and Seifert, 1994, Wilkes and Leatherbarrow, 1988, Johnson and Seifert, 1999). Thus, it is possible that after exposure to corrective information about nicotine, an individual could accurately state that nicotine is not the main cancer-causing constituent in tobacco and report accurate perceptions about the relative harm of products addressed in the message (surface updating), yet fail to accurately characterize the relative harm of a noncombustible nicotine-containing product if that product was not discussed in the message (global updating) (Johnson and Seifert, 1994).

Maintaining ‘coherence’ in a corrective message may help mitigate the CIE. Coherence refers to the explanatory power inherent in communicating the causal relationship between two things (Johnson and Seifert, 1994, Walter and Tukachinsky, 2020). Coherence can be achieved in correctives by providing a causal alternative - [it’s the toxicants generated during combustion, not nicotine, that are responsible for most disease risk from tobacco] – to fill the gap left by retracted information [nicotine does not cause cancer] (Lewandowsky et al., 2012, Walter and Murphy, 2018, Walter and Tukachinsky, 2020, Lewandowsky et al., 2020, Chan et al., 2017). Causal alternatives may be important because identifying and understanding causal relationships is necessary for constructing meaning and representing information in memory (Langston et al., 1999). A second strategy involves providing a reason the misinformation first came to be believed, which can prompt individuals to evaluate the original misperception more critically, helping to mitigate its effect (Chan et al., 2017).

Existing research on nicotine messaging has utilized casual alternatives in messaging experiments, finding that messages with causal alternatives significantly decreased, but did not eliminate the belief that nicotine causes cancer (Borland et al., 2012, Svenson et al., 2021, Yang et al., 2019, Villanti et al., 2019, Yang et al., 2019). Only one study additionally used the second strategy, where experimental messaging stated that companies that make nicotine replacement therapy (NRT) have attempted to communicate that nicotine is not a major cause of disease, but many people have not received this message (Borland et al., 2012). Despite including detailed information about both nicotine and the relative harm of noncombustible products, this factsheet did not significantly improve understanding of how smoking causes harm among in their sample of US adults who smoke, although they did find significant effects in other countries (Borland et al., 2012). The current experiment sought to extend this work by testing the effect of these combined strategies in nicotine corrective messages on accuracy of beliefs explicitly addressed in message content (e.g. indicators of surface updating) and inferential beliefs about different tobacco products not mentioned in the messages and switch intentions (e.g. indicators of global updating). Based on the CIE literature, we hypothesize that any message exposure would decrease a. beliefs that nicotine causes cancer and b. misperceptions about relative harm (H1) and that exposure to messaging with both corrective strategies will result in a. fewer misperceptions about relative harm of products not discussed in the messages and b. higher intention to completely switch to a noncombustible product than all other messaging conditions (H2). Given that the effect of these messaging strategies on surface updating (i.e., message recall) is not clear based on the CIE literature, we asked whether exposure to the different message conditions had a different effect on beliefs about: a. nicotine and b. relative harm perceptions discussed in the messages (RQ1).