The more you tell me how and why to avoid spreading COVID-19, the more I feel I can spare myself the trouble. Enhancing compliance with measures against COVID-19 by counteracting side-effects of appeals for preventive behaviour.

To curb the toll of COVID-19, citizens need to massively comply with precautionary measures. Once a vaccine will be available that compliance will mostly consist of getting vaccinated. Until then, it consists of things like wearing a mouth mask and social distancing. Since the start of the first COVID-19 outbreak in Belgium, however, our country has witnessed a decline of people's motivation to show those behaviours. Why have some people not followed the rules? Why have other people lost the motivation that they once had? Why has the relaxation of rules entailed more violations of remaining ones? Several explanations have been suggested, but arguably the most fundamental cause has been ignored: biases in risk perception (such as comparative optimism) and the ironic inflation of those biases by precisely those appeals meant to motivate people to follow precautionary rules. We will in a longitudinal study on representative samples in regions of Belgium differently affected by COVID-19 show how differences in risk perception between regions and changes in it over time are associated with differences and changes in the motivation to follow precautionary rules. We will through an experiment on a representative sample show which media messages enhance those biases and which messages reduce them. Our project will thus yield specific and readily applicable solutions to achieve an urgently needed better compliance with precautionary measures.