Using information provision and interactive risk maps to motivate testing for radon

Radon exposure in homes is a leading cause of lung cancer, but the rate at which householders test for it is low. In a pre-registered experiment with a nationally representative sample of adults (N = 1,700), we used psychological theory to design interventions to increase perceived risk from radon and motivate testing. Results show that providing information about radon increased belief that exposure would lead to negative consequences. Interactive maps that depict the geographical distribution of radon risk increased perceived likelihood of exposure, general worry and willingness to test for it, but the effects depend on the map's attributes. Maps that communicate risk using numeric frequencies of the number of homes in an area likely to be affected by radon (e.g., 1 in 5 homes) were more effective than ones that used simple statements (e.g., your home is at high risk). Adding an intermediate "moderate" risk category increased perceived risk compared to a binary high/low classification system among those in the moderate risk area, without altering perceptions of those at high risk. Other map features (colour and search functionality) had little impact. The best performing map led to 72% more people being willing to test for radon, compared to the map in use by the national Environmental Protection Agency at the time of the study. The results have implications for theories of risk perception and show the potential for techniques from psychological science to help mitigate a real-world environmental risk.