Testing the Limits of Inoculation-Generated Resistance

Abstract

This investigation explored three issues relevant to inoculation theory’s function. First, the stamina of inoculation-generated resistance was examined at 2-, 4-, and 6-week time intervals between treatment and persuasive attack. Second, inoculation and attack messages as booster treatments were compared. Finally, this study tested the ability of inoculation-generated resistance to withstand three persuasive attacks. Results from a 230-participant five-phase experiment indicate erosion of generated resistance with a longer time delay. However, booster treatments in the form of a second inoculation message demonstrate potential to lengthen the inoculation effect. In addition, generated resistance remained after three persuasive attacks.

Keywords:

• Attitude Change
• Boosters
• Inoculation
• Multiple Attacks
• Resistance

Notes

^1. Some of the conditions were not relevant to the present study.

^2. Due to significant sample disproportion, in each analysis separate tests were performed looking for possible sex differences (main and interaction). None were discovered.

^3. An independent sample t-test found no significant effect of using an inoculation booster message, as compared to not using one at all, as inoculated individuals who received a booster in the form of a repeated inoculation message (M = .14, SD = 2.62, n = 31) did not display significantly stronger attitudes toward the issue compared to inoculated individuals who did not (M = −.17, SD = 3.01, n = 29), t(58) = .43, p = .67, despite the fact that pattern of means favored the use of booster.

^4. An independent sample t-test indicated that inoculated individuals who received two boosters in the form of a repeated inoculation messages (M = .71, SD = 2.75, n = 26) displayed significantly stronger attitudes toward the issue after the attack compared inoculated individuals who did not receive any (M = −1.57, SD = 2.58, n = 32), t(56) = 3.24, p < .01, η² = .16.

^5. Within-subjects ANOVA effects were computed with the Greenhouse-Geisser adjustment, which corrects sphericity problems. The omnibus results of the repeated subjects ANOVAs, with Greenhouse-Geisser corrections, did not reveal significant attitudinal differences following each attack, F(1.79, 51.82) = .56, p = .56.

Additional information

Funding

This paper was not supported by external funding.