The Roots of Fear

Fear is not only more powerful than reason, however. It is also (sometimes absurdly) easy to evoke for reasons that also lie deep in our evolutionary past. Reacting to a nonexistent threat, such as fleeing from what you thought was a venomous snake that turned out to be a harmless one, isn't as dangerous as failing to react to actual threats. The brain is therefore wired to flinch first and ask questions later. As the 18th-century political theorist Edmund Burke observed, "No passion so effectually robs the mind of all its powers of acting and reasoning as fear." And when a candidate reminds voters of their fears about one issue, it can have a powerful spillover effect: "Fear that you cannot provide for your family because of an economic downturn can translate into hatred for immigrants," notes Emory's Westen.

The results of targeting the amygdala in a way that overrides the thoughtful cortex can be ludicrous or tragic, but frequently irrational. In a classic experiment, scientists compared people's responses to offers of flight insurance that would cover "death by any cause" or "death by terrorism." The latter, of course, is but a small subset of the former. Yet the specificity of the word "terrorism," combined with the stark images the word evokes, triggers the amygdala's fear response in a way that "by any cause" does not. Result: people are willing to spend more for terrorism insurance than death-by-any-cause insurance. The power of fear to overrule reason would have come as no surprise to the late Supreme Court justice Louis Brandeis. When "men feared witches," he wrote in 1927, they "burned women."

Fear makes people more likely to go to the polls and vote, which reflects the power of negative emotions in general. "Negative emotions such as fear, hatred and disgust tend to provoke behavior more than positive emotions such as hope and happiness do," says Harvard Universitypsychology researcher Daniel Gilbert. Perhaps paradoxically, the power of fear to move voters can be most easily understood when it fails to—that is, when an issue lacks the ability to strike terror in citizens' hearts. Global warming is such an issue. Yes, Hurricane Katrina was a terrifying example of what a greenhouse world would be like, and Al Gore's "An Inconvenient Truth" scared some people into changing their light bulbs to energy-miserly models. But barely 5 percent of voters rank global warming as the issue that most concerns them. There is little public clamor to spend the kind of money that would be needed to change our energy mix to one with a smaller carbon footprint, or to make any real personal sacrifices.

A big reason is that global warming, as an issue, lacks the characteristics that trigger fear, says Gilbert. The human brain has evolved to fear humans and human actions (such as airplane bombers), not accidents and impersonal forces (carbon dioxide, even when it is the product of human activities). If global warming were caused by the nefarious deeds of an evil empire—lofting military satellites that deliver carbon dioxide into the stratosphere, say, rather than the "innocent" actions of people heating their homes and driving their children to school—"the war on warming would be this nation's top priority," Gilbert wrote in the Los Angeles Times.

Besides needing that human component, events loom scariest when they pose a threat next week, not next decade or beyond. Climate change is already here, but the worst of it would arrive if the Antarctic and Greenland ice sheets melt, which is decades away. "The brain is adapted to deal with the here and now," says Gilbert—the lethal-tusked mastodon right over there, not the herd of them that will migrate through your encampment next spring. It's little wonder, then, that warnings about the eventual insolvency of Medicare or Social Security fail to move voters, and that global warming "fails to trip the brain's alarm," he says. But the prospect of illegal immigrants' changing the face of neighborhoods today does.

The primitive nature of fear means that it can be triggered most powerfully not by wordy arguments but by images that make a beeline for the brain's emotion regions. In Lyndon Johnson's 1964 "daisy" commercial, for instance, a little girl plucking the petals off a flower suddenly hears a boom and sees, in the distance, a mushroom cloud. The voice-over intones, "These are the stakes … Vote for President Johnson"—and not, implicitly, nuclear-war-mongering Barry Goldwater. The power of the now iconic ad was such that LBJ's campaign ran it only once. Not only was the ad endlessly discussed, but the mushroom-cloud image was firmly embedded in voters' memories.