Dread is a powerful force. The problem with dread is that it leads to terrible decision-making.

Slovic says all of this results from how our brains process risk, which is in two ways. The first is intuitive, emotional and experience based. Not only do we fear more what we can't control, but we also fear more what we can imagine or what we experience. This seems to be an evolutionary survival mechanism. In the presence of uncertainty, fear is a valuable defense. Our brains react emotionally, generate anxiety and tell us, "Remember the news report that showed what happened when those other kids took the bus? Don't put your kids on the bus."

The second way we process risk is analytical: we use probability and statistics to override, or at least prioritize, our dread. That is, our brain plays devil's advocate with its initial intuitive reaction, and tries to say, "I know it seems scary, but eight times as many people die in cars as they do on buses. In fact, only one person dies on a bus for every 500 million miles buses travel. Buses are safer than cars."

Unfortunately for us, that's often not the voice that wins. Intuitive risk processors can easily overwhelm analytical ones, especially in the presence of those etched-in images, sounds and experiences. Intuition is so strong, in fact, that if you presented someone who had experienced a bus accident with factual risk analysis about the relative safety of buses over cars, it's highly possible that they'd still choose to drive their kids to school, because their brain washes them in those dreadful images and reminds them that they control a car but don't control a bus. A car just feels safer. "We have to work real hard in the presence of images to get the analytical part of risk response to work in our brains," says Slovic. "It's not easy at all."

And we're making it harder by disclosing more risks than ever to more people than ever. Not only does all of this disclosure make us feel helpless, but it also gives us ever more of those images and experiences that trigger the intuitive response without analytical rigor to override the fear. Slovic points to several recent cases where reason has lost to fear: The sniper who terrorized Washington D.C.; pathogenic threats like MRSA and brain-eating amoeba. Even the widely publicized drunk-driving death of a baseball player this year led to decisions that, from a risk perspective, were irrational.