How do you tell fake news and conspiracy theories from the truth? It seems that lots of people can’t. A terrifying article in The Guardian ("Trapped in a hoax") reveals that 61% of the American public consistently endorses at least one conspiracy theory about subjects as diverse as where Barack Obama was born, whether climate change is real, that 9/11 was a government-planned attack, or whether childhood vaccines cause autism. Why is that terrifying? Because when challenged over the fabricati...