The cognitive bias that tripped us up during the pandemic

The issues with COVID communication are not limited to the statistics describing the spread and prevalence of the pandemic or the safe distance we should keep from others. Initially, we were told that “herd immunity” appears once 60%-70% of the population has gained immunity either through infection or vaccination. Later, with more studies and analysis this number was more accurately predicted to be around 90%-95%, which is meaningfully larger than the initial number. However, as shown in our study, the role of that initial number can be profound and a simple update wasn’t enough to remove it from people’s minds.