Herd immunity versus self-interest motives and norms effects on influenza vaccination intention.

OBJECTIVE: Promoting vaccine uptake is challenging. This research aimed to experimentally test the effect of communication strategies on influenza vaccine uptake intention. We hypothesized that the effect of descriptive norm level (10%-50%-90% of others vaccinated) on intention would vary according to whether the benefits are focused on the individual (self-interest motives) or others (herd-immunity motives). In particular, we predicted that low and high levels of norms would be detrimental in the herd-immunity condition (inverted-U pattern). In contrast, intention should increase linearly with the norm in the self-interest condition. METHOD: A representative sample of the Swiss population answered a survey containing vignettes manipulating norms (within-subjects variable) and motives (between-subjects variable, randomized). Their intention to receive a flu shot was measured for each situation. RESULTS: As expected, a significant simple quadratic effect of norm was obtained in the herd-immunity condition. No linear effect was found in the self-interest condition. A main effect of motives was found: The intention was higher in the herd-immunity condition than in the self-interest condition. Sensitivity analysis showed that our results are robust, except for the simple quadratic effect in the herd-immunity condition. CONCLUSIONS: Herd-immunity motive is more motivating to induce intention to vaccinate against influenza. The effect of norms appears to depend on the motive, and average levels of norms seem to be more motivating than very low and very high levels. The way vaccination is presented can influence adoption rates, and this should be considered when vaccination rates are communicated in the media. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Contextual variation in cognitive performance of older adults: Demonstration of an age-of-examiner effect.

Objective: Consistent with research on stereotype threat, when examiners' characteristics make a stereotype of the participant group salient, it can hamper participants' performance. We hypothesized that younger examiners represent a subtle element activating age stereotypes, leading older people to perform worse as examiners' age decreases. Method: We analyzed data from the Survey of Health, Ageing, and Retirement in Europe (SHARE; NParticipants = 32768) and Vivre-Leben-Vivere studies (VLV, Nparticipants = 960), wherein older people were tested at home by examiners of different ages on eight cognitive tasks. Results: Our results indicate that participants' performance on five tasks was positively linked to examiners' age, showing that the older the examiner, the better the participants' performance. Conclusions: These findings could have implications for the current assessment of memory performance among older adults.