Explaining and reducing the public’s expectations of antibiotics: A utility-based signal detection theory approach

To tackle antibiotic resistance, an unfolding global public health threat, we need to better understand why people expect antibiotics for self-limiting infections because this drives unnecessary consumption of antibiotics. Here, we used a utility-based signal detection theory to explain how people form these expectations by considering their diagnostic uncertainty (e.g., “Is this a bacterial infection?”) and the expected utility they associate with their decisions (e.g., “What are the costs of taking antibiotics?”). To test the explanation, we created two types of interventions—focusing on reducing diagnostic uncertainty and increasing the saliency of costs of overuse (to self and others)—to lower inappropriate expectations of antibiotics. In two pre-registered vignette-based experiments (N=1,773; general UK adult population), both types of interventions decreased expectations and intentions to request antibiotics compared with a baseline group. We discuss how the theory can inform public health campaigns and stimulate further research.