Worry

Inside the Mind of Worry

By DAVID ROPEIK

Cambridge, Mass.

WE make all sorts of ostensibly conscious and seemingly rational choices when we are aware of a potential risk. We eat organic food, max out on multivitamins and quickly forswear some products (even whole technologies) at the slightest hint of danger. We carry guns and vote for the candidate we think will keep us safe. Yet these choices are far from carefully considered — and, surprisingly often, they contravene reason. What’s more, while our choices about risk invariably feel right when we make them, many of these decisions end up putting us in greater peril.

Researchers in neuroscience, psychology, economics and other disciplines have made a range of discoveries about why human beings sometimes fear more than the evidence warrants, and sometimes less than the evidence warns. That science is worth reviewing at length. But one current issue offers a crash course in the most significant of these findings: the fear of vaccines, particularly vaccines for children.

In a 2011 Thomson Reuters/NPR poll, nearly one parent in three with a child under 18 was worried about vaccines, and roughly one American in four was concerned about the value and safety of vaccines in general. In the same poll, roughly one out of every five college-educated respondents worried that childhood vaccination was connected with autism; 7 percent said they feared a link with Type 1 diabetes.

Based on the evidence, these and most other concerns about vaccines are unfounded. A comprehensive report last year from the Institute of Medicine is just one of many studies to report that vaccines do not cause autism, diabetes, asthma or other major afflictions listed by the anti-vaccination movement.

Yet these fears, fierce and visceral, persist. To frustrated doctors and health officials, vaccine-phobia seems an irrational denial of the facts that puts both the unvaccinated child and the community at greater risk (as herd immunity goes down, disease spread rises). But the more we learn about how risk perception works, the more understandable — if still quite dangerous — the fear of vaccines becomes.

Along with many others, the cognitive psychologists Paul Slovic of the University of Oregon and Baruch Fischhoff of Carnegie Mellon University have identified several reasons something might feel more or less scary than mere reason might suppose. Humans subconsciously weigh the risks and benefits of any choice or course of action — and if taking a particular action seems to afford little or no benefit, the risk automatically feels bigger. Vaccinations are a striking example. As the subconscious mind might view it, vaccines protect children from diseases likemeasles and pertussis, or whooping cough, that are no longer common, so the benefit to vaccination feels small — and smaller still, perhaps, compared to even the minuscule risk of a serious side effect. (In actuality, outbreaks of both of these infections have been more common in recent years, according to the Centers for Disease Control and Prevention.) Contrast this with how people felt in the 1950s, in the frightening days of polio, when parents lined their kids up for vaccines that carried much greater risk than do the modern ones. The risk felt smaller, because the benefit was abundantly clear.

Professor Slovic and Professor Fischhoff and others have found that a risk imposed upon a person, like mandatory vaccination programs (nearly all of which allow people to opt out), feels scarier than the same risk if taken voluntarily. Risk perception also depends on trust. A risk created by a source you don’t trust will feel scarier. The anti-vaccination movement is thick with mistrust of government and the drug industry. Finally, risks that are human-made, like vaccines, evoke more worry than risks that are natural. Some parents who refuse to have their kids vaccinated say they are willing to accept the risk of the disease, because the disease is “natural.”

Still, shouldn’t our wonderful powers of reason be able to overcome these instinctive impediments to clear thinking? The neuroscience of fear makes clear that such hope is hubris. Work on the neural roots of fear by the neuroscientist Joseph LeDoux of New York University, and others, has found that in the complex interplay of slower, conscious reason and quicker, subconscious emotion and instinct, the basic architecture of the brain ensures that we feel first and think second. The part of the brain where the instinctive “fight or flight” signal is first triggered — the amygdala — is situated such that it receives incoming stimuli before the parts of the brain that think things over. Then, in our ongoing response to potential peril, the way the brain is built and operates assures that we are likely to feel more and think less. As Professor LeDoux puts it in “The Emotional Brain”: “the wiring of the brain at this point in our evolutionary history is such that connections from the emotional systems to the cognitive systems are stronger than connections from the cognitive systems to the emotional systems.”

And so we have excessive fear of vaccines. But just as we are too afraid of some things, this same “feelings and facts” system works the other way too, sometimes leaving us inadequately concerned about bigger risks. A risky behavior you engage in voluntarily and that seems to afford plenty of benefit — think sun-tanning for that “nice, healthy glow” — feels less dangerous. A societal risk, well off in the future, tends not to trigger the same instinctive alarm — in part, because the hazard isn’t singling any one of us out, individually. This helps explain why concern over climate change is broad, but thin.

Though it may be prone to occasional errors, our risk-perception system isn’t all bad. After all, it has gotten us this far through evolution’s gantlet. But a system that relies so heavily on emotion and instinct sometimes produces risk perceptions that don’t match the evidence, a “risk perception gap” that can be a risk in itself. We do have to fear the dangers of fear itself.

In this remarkable era of discovery about how our brains operate, we have discovered a great deal about why the gap occurs, and we can — and should — put our detailed knowledge of risk perception to use in narrowing the risk-perception gap and reducing its dangers. As the Italian philosopher Nicola Abbagnano advised, “Reason itself is fallible, and this fallibility must find a place in our logic.” Accepting that risk perception is not so much a process of pure reason, but rather a subjective combination of the facts and how those facts feel, might be just the step in the human learning curve we need to make. Then, maybe, we’ll start making smarter decisions about vaccines and other health matters.

David Ropeik is an instructor at the Harvard Extension School and the author of “How Risky Is It, Really? Why Our Fears Don’t Always Match the Facts.”