Mechanisms of self-persuasion intervention for HPV vaccination: Testing memory and autonomous motivation

Optimizing a self-persuasion intervention app for adolescent HPV vaccination requires investigating its hypothesized mechanisms. Guided by the experimental medicine approach, we tested whether (a) self-persuasion intervention components (verbalize vaccination reasons, choose HPV topics) changed putative mechanisms (memory, autonomous motivation) and (b) measures of the putative mechanisms were associated with HPV vaccination. These are secondary analyses from a randomized 2 (cognitive processing: verbalize reasons vs. listen) × 2 (choice: choose HPV topics vs. assigned) factorial trial (Tiro et al., 2016). Undecided parents (N = 161) with an unvaccinated child (11-17 years old) used the self-persuasion app, recalled reasons for vaccination (memory measure), and completed an autonomous motivation measure. Adolescent vaccination status was extracted from electronic medical records 12 months postintervention. The verbalize component resulted in greater recall accuracy of vaccination reasons (p < .001); however, the choose topics component did not increase autonomous motivation scores (p = .74). For associations with HPV vaccination, recall accuracy was not associated (ps > .51), but autonomous motivation scores significantly predicted vaccination (ps < .03), except when controlling for baseline motivation (p = .22). The intervention app engages parents in reasons for vaccination; however, memory may not be a viable mechanism of vaccination. Although the intervention did not affect autonomous motivation, associations with vaccination status suggest it is a viable intervention target for HPV vaccination but alternative strategies to change it are needed. Future testing of a refined app should examine implementation strategies to optimize delivery in clinical or community settings. (PsycInfo Database Record (c) 2022 APA, all rights reserved).