The science of stoking fear

Punam Anand Keller, a Dartmouth College professor who's researched marketing and consumer behavior, says the tactic is everywhere — from the dentist warning of the severe health dangers if you don't floss, to commercials that lead with the dire consequences of drunk driving.

• "It only works when people believe in the fear arousing part of the message," Keller says. "For those people who don’t believe, then the message isn’t effective."

Constant "fears and scares," particularly in politics, make a lasting imprint says Barry Glassner, a sociologist and author of “The Culture of Fear."

• Glassner says fear-based messaging creates the same visceral, fight-or-flee response as coming upon a wild animal: Rational thinking gets much harder.