Banas and Miller use the “inoculation theory” developed by psychologist William McGuire in the 1960s to test whether human minds can be made “conspiracy resistant.” McGuire posited that humans can be fortified from the influence of persuasive messages before the messages are received.
Inoculation works through a two-part process. First, the human subject is warned they may be receiving an undesirable message at some point in the future. Second, the human subject is taught counter-arguments to the anticipated message. Inoculation is sometimes seen in political campaigns and public health initiatives. Adolescents, for instance, may first be warned of peer pressure to drink before being cautioned about the dangers of underage drinking.
To test whether inoculation would work to preemptively counteract conspiracy theories, Banas and Miller showed Loose Change: Final Cut to a group of 312 people ranging in age from 18 to 35. Loose Change: Final Cut is a film that declares “the official story of 9/11 … is false.” Prior to seeing the film, subjects were warned of a pending information threat – the first phase of inoculation (a motivation for the individual to prepare to protect their beliefs).
The group was divided into thirds: a control group and two inoculation groups. The first inoculation group was asked to read one of two statements. The first statement contained a page of facts designed to dispute the premise of Loose Change: Final Cut. The second statement contained logical arguments designed to dispute the premise of Loose Change: Final Cut.
The second inoculation group also read the two statements given to the first group as well as a third statement designed to counteract the inoculation. This third statement contained no arguments at all against Loose Change: Final Cut but, instead, warned participants that “people out there” want to keep them from accessing dangerous information and they could choose to be “independent thinkers” or “sheep.”
After viewing the film, study participants were asked to complete a survey about their attitudes on the “official story” of the September 11 attacks. Subjects who received the inoculations were less likely to believe Loose Change: Final Cut versus the control group. However, the inoculations had less impact among subjects who had first been warned to be “independent thinkers” instead of “sheep.” This, Banas and Miller explain,
… may be derived from using the loaded terms ‘‘sheep’’ and ‘‘independent thinker,’’ both of which strongly align with core American values. Although independent thinking may be perceived as an attractive quality by participants, it was used in the metainoculation to promote the rejection of an empirically accurate and logically sound deconstruction of a rather outrageous conspiracy theory, thereby creating the type of influence participants were likely trying to avoid.