Dual-process theories to counter the anti-vaccination movement

Vaccine hesitancy is a problem attracting growing attention and concern. In this paper, we discuss why anti-vaccination messages are influential and which pro-vaccine messages can be effective to address vaccine hesitancy from the perspective of dual-process theories of cognitive functioning. The functioning of the human brain can be characterized by two different types of cognitive functioning: intuitive System 1, which is evolutionarily old, fast, and automatic; and analytical System 2, which is evolutionarily recent, slow, and deliberative. Anti-vaccination messages that inspire fear activate System 1, and vaccine recommendation messages that use statistics activate System 2. System 1 has a greater influence on judgment than System 2. The processing of System 1 is called “trajectory.” Even if adequate knowledge about the effectiveness and safety of vaccination is input to System 2, vaccine hesitancy cannot be easily erased once it is generated by System 1. We suggest that vaccine recommendation messages should target System 1 in addition to System 2, to counter anti-vaccination messages and address vaccine hesitancy.