Inoculation theory suggests that an individual’s belief can be less easily influenced or changed by being pre-exposed to inoculation messages which are weaker versions of future arguments.
Just like in vaccination, a person is ‘inoculated’ from persuasions as he would then seek information to bolster his current belief. It should be noted that the inoculation messages should be strong enough to challenge the individual but also weak enough for it to be refuted. It is believed that those who have been previously exposed to such messages develop a resistance to future attacks or pressures from their peers, the mass media, temptations, and other sources of persuasions. This theory was developed in 1961 by William James McGuire, an American Psychologist who extensively researched on the psychology of persuasion. McGuire was motivated to study people’s resistance to persuasion when nine American prisoners of war elected to remain with their Korean captors.