10 Ways We Get the Odds Wrong

The word radiation stirs thoughts of nuclear power, X-rays, and danger, so we shudder at the thought of erecting nuclear power plants in our neighborhoods. But every day we're bathed in radiation that has killed many more people than nuclear reactors: sunlight. It's hard for us to grasp the danger because sunlight feels so familiar and natural.

Our built-in bias for the natural led a California town to choose a toxic poison made from chrysanthemums over a milder artificial chemical to fight mosquitoes: People felt more comfortable with a plant-based product. We see what's "natural" as safe—and regard the new and "unnatural" as frightening.

Any sort of novelty—including new and unpronounceable chemicals—evokes a low-level stress response, says Bruce Perry, a child psychiatrist at Child Trauma Academy. When a case report suggested that lavender and tea-tree oil products caused abnormal breast development in boys, the media shrugged and activists were silent. If these had been artificial chemicals, there likely would have been calls for a ban, but because they are natural plant products, no outrage resulted. "Nature has a good reputation," says Slovic. "We think of natural as benign and safe. But malaria's natural and so are deadly mushrooms."

X. We Should Fear Fear Itself

Why worrying about risk is itself risky.

Though the odds of dying in a terror attack like 9/11 or contracting Ebola are infinitesimal, the effects of chronic stress caused by constant fear are significant. Studies have found that the more people were exposed to media portrayals of the 2001 attacks, the more anxious and depressed they were. Chronically elevated stress harms our physiology, says Ropeik. "It interferes with the formation of bone, lowers immune response, increases the likelihood of clinical depression and diabetes, impairs our memory and our fertility, and contributes to long-term cardiovascular damage and high blood pressure."

The physiological consequences of overestimating the dangers in the world—and revving our anxiety into overdrive—are another reason risk perception matters. It's impossible to live a risk-free life: Everything we do increases some risks while lowering others. But if we understand our innate biases in the way we manage risks, we can adjust for them and genuinely stay safer—without freaking out over every leaf of lettuce.

Maia Szalavitz is the co-author of The Boy Who Was Raised as a Dog: And Other Stories From a Child Psychiatrist's Notebook.

Mortal Threats

How good is your grasp of risk?

1. What's more common in the United States, (a) suicide or (b) homicide?
2. What's the more frequent cause of death in the United States, (a) pool drowning or (b) falling out of bed?
3. What are the top five causes of accidental death in America, following motor-vehicle accidents, and which is the biggest one?
4. Of the top two causes of nonaccidental death in America, (a) cancer and (b) heart disease, which kills more women?
5. What are the next three causes of nonaccidental death in the United States?
6. Which has killed more Americans, bird flu or mad cow disease?
7. How many Americans die from AIDS every year, (a) 12,995, (b) 129,950, or (c) 1,299,500?
8. How many Americans die from diabetes every year? (a) 72,820, (b) 728,200, or (c) 7,282,000?
9. Which kills more Americans, (a) appendicitis or (b) salmonella?
10. Which kills more Americans, (a) pregnancy and childbirth or (b) malnutrition?

ANSWERS (all refer to number of Americans per year, on average):

1. a
2. a
3. In order: drug overdose, fire, choking, falling down stairs, bicycle accidents
4. b
5. In order: stroke, respiratory disease, diabetes
6. No American has died from either one
7. a
8. a
9. a
10. b

Sources:

• Centers for Disease Control and Prevention (Division of Vital Statistics)
• National Transportation Safety Board