Weight-of-Evidence Strategies to Mitigate the Influence of Messages of Science Denialism in Public Discussions

In mass media, the positions of science deniers and scientific-consensus advocates are repeatedly presented in a balanced manner. This false balance increases the spread of misinformation under the guise of objectivity. Weight-of-evidence strategies are an alternative, in which journalists lend weight to each position that is equivalent to the amount of evidence that supports the position. In public discussions, journalists can invite more advocates of scientific consensuses than science deniers (outnumbering) or they can employ warnings about the false-balance effect prior to the discussions (forewarning). In three pre-registered laboratory experiments, we tested the efficacy of outnumbering and forewarning as weight-of-evidence strategies to mitigate science deniers’ influence on individuals’ attitudes towards vaccination and their intention to vaccinate. We explored whether advocates’ responses to science deniers (rebuttal) and audiences’ issue involvement moderate the efficacy of these strategies. A total of N = 887 individuals indicated their attitudes towards vaccination and their intention to vaccinate before and after watching a television (TV) discussion. The presence and absence of forewarning, outnumbering and rebuttal were manipulated between subjects; participants also indicated their individual issue involvement. We obtained no evidence that outnumbering mitigates damage from denialism, even when advocates served as multiple sources. However, forewarning about the false-balance effect mitigated deniers’ negative effects. Moreover, the protective effect was independent of rebuttal and issue involvement. Thus, forewarnings can serve as an effective, economic and theory-driven strategy to counter science denialism in public discussions, at least for highly educated individuals such as university students.

Stefan Müller (Science Denier 1): 'The lack of safety is an important issue with the dysomeria vaccine. The side effects and risks of the vaccine are incalculable. As a patient, you do not know how the body reacts to the vaccine before administration. Even if you feel healthy immediately after the shot, harmful substances may have entered your body. Doctors cannot guarantee in advance that there will not be any complications. In my opinion, you cannot expect any fellow citizen to vaccinate as long as the vaccine is not 100% safe. Surely, it is not too much to ask that a product injected into a healthy human body be 100% safe.' Florian Hantzsch (Interviewer): 'Thank you, Mr. Müller. Mr. Jürgen Schmidt from the Health Office in Neustadt, how do you respond to that?' Jürgen Schmidt (Science Advocate 1): 'Mr. Müller demands 100% safety from the vaccine against dysomeria. In science, this argument is called impossible expectation. It is an impossible expectation because science can never guarantee 100% safety for any medical product, neither for aspirin nor for heart surgery. Any treatment poses a residual risk of complications for patients either during or after treatment. The scientific evidence is clear: The vaccine against dysomeria is a safe way to avoid the disease. The risk of dysomeria by far exceeds the risk from vaccination. This is why we, the Health Office in Neustadt, recommend the vaccination against the DS virus for citizens of all ages. And please let me add the following regarding the safety of the vaccine: We follow a very strict protocol to ensure the high quality of vaccines in the Federal States. This is also demonstrated by the fact that every batch of the vaccine against dysomeria is monitored constantly and independently screened by official control laboratories.'

Video
Florian Hantzsch (Interviewer): 'Vaccines protect against diseases; however, pharmaceutical companies also make money from producing vaccines. A question arises: Who actually benefits from vaccination, Mr. Müller?' Stefan Müller (Science Denier 1): 'At the end of the day, it is not about the health of the individual citizen. It is about the financial interests of large companies and government institutions. The pharmaceutical industry earns a huge annual profit with the sale of the vaccine against dysomeria. The government can multiply the profit tremendously with official vaccination recommendations. If we put two and two together, then anyone can see this perfidious collaboration between the responsible parties. In the end, all those who have something to say in this system are connected in a way, and only the ordinary citizen is left outand is expected to do one thing: Stay silent and keep on vaccinating.' Florian Hantzsch (Interviewer): 'Thank you, Mr. Müller. Mr. Jürgen Schmidt from the Health Office in Neustadt, how do you respond to that?' Jürgen Schmidt (Science Advocate 1): 'Mr. Müller suspects a secret conspiracy behind the distribution of the vaccine against dysomeria. This perspective completely ignores that a large proportion of the research that demonstrates the benefits of vaccination for society and each individual is conducted by independent scientists all over the world. In addition, such conspiratorial claims discredit the prosocial motives of all our healthcare system's employees. Let's stay with the facts: In regions where the vaccine against dysomeria is used, people live a healthier life. This has been demonstrated several times. The major goal of governmental health institutions like our office is to maintain and improve the health of every single citizen in the country. I very much regret that Mr. Müller has lost trust in our institution and our effort. The Standing Committee on Vaccination STIKO, which is responsible for vaccination recommendations in the Federal States, is composed of independent experts who are appointed for a period of three years. The members are an independent advisory group, and the meetings and protocols of the STIKO, as well as possible conflicts of interest among the members, are open to the public and available via webcast. Whatever Mr. Müller is suggesting here, the fact is: The vaccine improves the health standards of all individuals, and that is why we recommend it for citizens of all ages.' Stefan Müller (Science Denier 1): 'The lack of safety is an important issue with the dysomeria vaccine. The side effects and risks of the vaccine are incalculable. As a patient, you do not know how the body reacts to the vaccine before administration. Even if you feel healthy immediately after the shot, harmful substances may have entered your body. Doctors cannot guarantee in advance that there will not be any complications. In my opinion, you cannot expect any fellow citizen to vaccinate as long as the vaccine is not 100% safe. Surely, it is not too much to ask that a product injected into a healthy human body be 100% safe.'

Video
Florian Hantzsch (Interviewer): 'Vaccines protect against diseases; however, pharmaceutical companies also make money from producing vaccines. A question arises: Who actually benefits from vaccination, Mr. Müller?' Stefan Müller (Science Denier 1): 'At the end of the day, it is not about the health of the individual citizen. It is about the financial interests of large companies and government institutions. The pharmaceutical industry earns a huge annual profit with the sale of the vaccine against dysomeria. The government can multiply the profit tremendously with official vaccination recommendations. If we put two and two together, then anyone can see this perfidious collaboration between the responsible parties. In the end, all those who have something to say in this system are connected in a way, and only the ordinary citizen is left outand is expected to do one thing: Stay silent and keep on vaccinating.' Stefan Müller (Science Denier 1): 'The lack of safety is an important issue with the dysomeria vaccine. The side effects and risks of the vaccine are incalculable. As a patient, you do not know how the body reacts to the vaccine before administration. Even if you feel healthy immediately after the shot, harmful substances may have entered your body. Doctors cannot guarantee in advance that there will not be any complications. In my opinion, you cannot expect any fellow citizen to vaccinate as long as the vaccine is not 100% safe. Surely, it is not too much to ask that a product injected into a healthy human body be 100% safe.'

Supplementary Material 2. Forewarning received by control group in Experiments 2 and 3. Note: original materials were in German.
Note! Data protection is very important to us; therefore, we take protection of your data very seriously. We always want you to feel safe when using our Internet services and to know exactly which data are stored and used. We follow the principles of data avoidance and data economy. The basis for this is the law applicable in Germany in the form of the Federal Data Protection Act and the EU's Basic Data Protection Regulation.
All access to our websites and all file retrievals are recorded for statistical and security purposes. In addition, storage of accesses serves to guarantee system stability. To determine this data, our sender, as well as other community facilities, use so-called pixel-code data, which are collected and stored in anonymous form for optimisation and study purposes. These measurements were developed for data protection. Your identity is always protected. You will not receive any advertising via the system. We make every effort to protect your personal data from unauthorised access by means of organisational measures. Please note that data security on the Internet cannot be guaranteed when communicating via e-mail and that we recommend sending confidential information by post.
Enjoy the show.