No one knows where or how fast a new virus will spread. We cannot calculate the risks with confidence, and we will know only in hindsight whether we overreacted or underreacted. Given this uncertainty, how we respond to a viral outbreak is as crucial as the nature of the pathogen. And how we respond to the COVID-19 coronavirus should be guided by what we have learned from past viral epidemics. - By Gerd Gigerenzer.