Inoculation theory

Inoculation theory is a social psychological/communication theory that explains how an attitude or belief can be made resistant to persuasion or influence, in analogy to how a body gains resistance to disease.^[1][2] The theory uses medical inoculation as its explanatory analogy but instead of applying it to disease, it is used to discuss attitudes. It has applicability to public campaigns targeting misinformation and fake news.

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.^[3] Inoculation theory functions to confer resistance of counter-attitudinal influences from such sources as the media, advertising, interpersonal communication, and peer pressure.

The theory posits that weak counterarguments generate resistance within the receiver, enabling them to maintain their beliefs in the face of a future, stronger challenge. 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 counterargument, hence the medical analogy of a vaccine.

Inoculating messages can be on the same topic as the threatening message (refutational same) or on a similar topic (refutational different). The effect of the inoculating message can be amplified by making the message of vested and immediate importance to the receiver (based on Jack Brehm's psychological reactance theory). Post-inoculation talk can further spread inoculation effects to their social network, and the act of talking to others can additionally strengthen resistance to attitude change.

Therapeutic inoculation is a recent extension in which an inoculation message is presented to those without the targeted belief or attitude in place.^[4] Applied in this way, an inoculation message can both change an existing position and make that new position more resistant to future attacks.