The One-Way Drop

Somewhere in your kitchen there is a glass, and you trust it. You washed it, you shelved it, and if I dropped one bead of ink into it right now, you would never drink from it again. Not after a rinse. Not after ten rinses. One drop, and the glass is ruined in a place no sponge can reach. Hold that feeling. This episode is about the people who turned that feeling into law, and about the one room in the world where the feeling was finally told no. In 1986, in a laboratory at the University of Pennsylvania, a researcher named Paul Rozin dipped a dead cockroach into a glass of apple juice. The roach was sterilized. The subjects watched the sterilizing. They knew, as a matter of certified fact, that the juice was clean. Nobody drank it. In another test, people labeled a bottle of plain sugar with the word poison in their own handwriting, and then flinched at their own label. Nothing touched the sugar except a word. The word was enough.