How do people form beliefs about novel risks, with which they have little or no experience? Motivated by survey data we collected in 2020, which showed that beliefs about Covid’s lethality depended on a range of personal experiences in unrelated domains, we build a model based on the psychology of selective memory. When a person thinks about an event, different experiences compete for retrieval, and retrieved experiences are used to simulate the event based on how similar they are to it. The model yields predictions on how experiences interfere with each other in recall and how non domain-specific experiences bias beliefs based on their similarity to the assessed event. We test these predictions using data from our Covid survey and from a primed-recall experiment about cyberattack risk. Experiences and their measured similarity to the cued event successfully help explain beliefs, with patterns consistent with our theory. Our approach offers a new, structured way to study and jointly account for systematic biases and substantial belief heterogeneity.
Keywords: Similarity, selective recall, disagreement