"The obvious and instinctive response is to fight falsehoods with facts. Correcting falsehoods is important. People make poor decisions when they believe lies and trust liars: they expose their kids and others to deadly diseases, vote for the wrong candidate, or attempt to kill innocent people. But in fact, vaccines don’t cause autism; President Obama was born in Hawaii; and Comet Ping Pong pizzeria sells pizza, not children. But there is one big drawback to fact-checking and lie-correcting. The more often a lie is repeated, even in the context of debunking it, the more believable it becomes. Familiarity provides the impression of truth. Furthermore, false statements, even when we know they are false, influence our emotional response to people and events."