Revenge of the Tipping Point: Overstories, Superspreaders, and the Rise of Social Engineering

by Malcolm Gladwell

Enter the aerosolists. One of the most important tools in the aerosol world is an aerodynamic particle sizer, or APS machine. It’s a box, fed by a funnel. It’s the human equivalent of the magic box that Donald Stedman invented for measuring the emissions of cars. If you breathe into it, it runs the air that comes out of your mouth through a series of lasers, which count the number and measure the size of every aerosol particle in your breath. In one crucial early experiment, William Ristenpart’s lab gathered a group of volunteers and had them breathe into an APS. The study subjects repeated vowel sounds. They shouted and whispered. They performed “vocalizations.” And the researchers confirmed what all those UFO sightings over the years had suggested: A small group of their sample was off the charts.