Vaccine Hesitancy and Betrayal Aversion

Area of Science:

• Behavioral Economics
• Public Health
• Social Psychology

Background:

• Vaccine hesitancy is a complex public health issue with multifaceted determinants.
• Existing measures of vaccine hesitancy may not fully capture underlying psychological factors influencing vaccination decisions.
• Betrayal aversion, a psychological construct, describes an individual's reluctance to engage in situations where betrayal is a risk, particularly in contexts of trust.

Purpose of the Study:

• To investigate whether betrayal aversion is a significant, yet unmeasured, factor contributing to vaccine hesitancy.
• To quantify the impact of betrayal aversion on vaccine acceptance across different potential sources of betrayal.
• To assess the efficacy of a standard message intervention in mitigating betrayal aversion-driven vaccine hesitancy.

Main Methods:

• A pre-registered vignette experiment was conducted with 888 United States residents recruited via Amazon Mechanical Turk in March 2021.
• Participants completed a survey instrument designed to measure betrayal aversion and vaccine acceptance.
• An exogenous message intervention was introduced to evaluate its effect on betrayal aversion.

Main Results:

• Over one-third of participants exhibited betrayal averse preferences.
• Betrayal aversion led to an 8-26% decline in vaccine acceptance, with the greatest reductions observed when betrayal risk was attributed to scientists or government.
• A standard message intervention proved ineffective in reducing betrayal aversion.

Conclusions:

• Betrayal aversion is a crucial, unaddressed preference construct influencing vaccine decision-making.
• Current vaccine hesitancy assessments may overlook this significant psychological barrier.
• Targeted interventions addressing betrayal aversion are needed to improve vaccine uptake, particularly when trust in institutions is a factor.