Inoculation theory explains how an attitude or belief can be protected against influence in much the same way a body can be protected against disease–through preexposure to weakened versions of a stronger, future threat (see Compton, 2013; Compton & Pfau, 2005). Inoculation theory explains how an attitude or belief can be protected against influence in much the same way a body can be protected against disease–through preexposure to weakened versions of a stronger, future threat (see Compton, 2013; Compton & Pfau, 2005). The theory was developed by social psychologist William J. McGuire in 1961 to explain how attitudes and beliefs change, and more specifically, how to keep existing attitudes and beliefs consistent in the face of attempts to change them. Inoculation theory functions as a strategy to protect attitudes from change–to confer resistance to counter-attitudinal influences, whether such influences take the form of direct attacks, indirect attacks, sustained pressures, etc., from such sources as the media, advertising, interpersonal communication, peer pressure, and temptations. The theory posits that weak counterarguments–arguments that are refuted–generate resistance within the receiver, enabling them to maintain their beliefs in the face of a future, stronger attack. Following exposure to weak counterarguments (e.g., counterarguments that have been paired with refutations), the receiver will then seek out supporting information to further strengthen their threatened position. The held attitude or belief becomes resistant to a stronger attack, hence the medical analogy of a vaccine. Inoculation is a theory developed to strengthen existing attitudes and beliefs by building resistance to future counterarguments. For inoculation to be successful, the inoculation message recipient experiences threat (a recognition that a held attitude or belief is vulnerable to change, see Compton, 2009) and is exposed to and/or engages in refutational preemption (defenses against potential counterarguments). The arguments that are presented in an inoculation message must be strong enough to initiate motivation to maintain current attitudes and beliefs, but weak enough that the receiver will be able to refute the counterargument (Compton, 2013; McGuire, 1964). Inoculation theory has been studied and tested through decades of scholarship, including experimental research in and out of laboratory settings. Inoculation theory is used today as part of the suite of tools used by those engaged in shaping or manipulating public opinion. These contexts include: politics (e.g., Pfau et al., 1990; see Compton & Ivanov, 2013, for a review), health campaigns (e.g., Pfau & VanBockern, 1994; see Compton, Jackson, & Dimmock, 2016, for a review), marketing (e.g., Compton & Pfau, 2004), education (Compton, 2011), and science communication (van der Linden et al., 2017), among others. (See Banas & Rains, 2010, for a meta-analysis, and Compton, 2013, for a narrative overview.) The inoculation process is analogous to the medical inoculation process from which it draws its name; the analogy served as the inaugural exemplar for how inoculation confers resistance. As McGuire (1961) initially explained, medical inoculation works by exposing the body to a weakened form of a virus—strong enough to trigger a response (i.e., the production of antibodies), but not so strong as to overwhelm the body's resistance. Attitudinal inoculation works the same way: Expose the receiver to weakened counterarguments, triggering a process of counterargument which confers resistance to later, stronger persuasive messages. This process works like a metaphorical vaccination: the receiver becomes immune to attacking messages that attempt to change their attitudes or beliefs. Inoculation theory suggests that if one sends out messages with weak counterarguments, an individual can build immunity to stronger messages and strengthen their original attitudes toward an issue.