Every conspiracy theory starts as a notion nestled safely in someone’s head, just waiting for a chance to spread. Some are harmless fun (Keanu Reeves is immortal), while others are deadly (vaccines cause autism). But all run on the same psychological tricks: They make ­believers feel more in control of a chaotic world. Folks cling to stories that affirm their beliefs, explain away mysteries, and provide scapegoats for their troubles. But there are many paths to infamy. Which will you choose?

Flow chart for how conspiracies start and proliferate
Giacomo Gambineri