Optimism: Science Study Shows Optimists Block Out Information

The teenager who thinks she can have unprotected sex without suffering any consequences. The alcoholic who thinks he can have one little drink without falling off the wagon. The politician who keeps compromising even though his opponents roll him every time. It’s called unrealistic optimism. (President Obama, whose base sometimes cringes at his readiness to compromise with opponents, is on record as an "eternal optimist.")

In contrast to plain optimism, the unrealistic kind characterizes people who continue to believe there will be a rosy outcome despite clear evidence and even personal experience to the contrary. While reasonable optimism serves us well—it lowers stress and anxiety, and can even reduce the risk of developing various diseases and help us recover faster, according to studies like this one—the unrealistic kind can backfire badly. It's part of why people save too little for retirement (“things will work out somehow”), fail to use sunscreen (“skin cancer? no way”), and don’t make prenuptial agreements (most people estimate their risk of divorce as zero percent.) Scientists have long wondered how foolish optimism manages to survive, especially since one of the key tenets of how the brain learns is that we continuously update our knowledge in light of experience and new information. Now, in the first study of its kind, neuroscientists have pinpointed the brain circuits that underlie unrealistic optimism. What they found is that the frontal lobes, which analyze information, basically look the other way when unrealistic optimists receive information that undercuts one of their rosy beliefs.

For the study, published this week in Nature Neuroscience, scientists focused on a particular form of optimism, namely, underestimating the likelihood that bad things will occur, as might the condomless teen or compromising politician. The researchers projected short descriptions of 80 bad events (having your car stolen, developing Parkinson’s disease, being the victim of Internet fraud, having a mouse in your house ...) one at a time onto a screen that each of 19 volunteers could see while they lay inside an MRI tube. The volunteers estimated the probability that each unfortunate event would befall them. Next, the scientists showed them the actual probabilities and asked them to again estimate their own chances of, say, being cheated on by a spouse or being fired. Finally, the volunteers filled in a personality questionnaire measuring their level of optimism.

The good news is that people were not completely incapable of learning: they revised their estimates of the probability that they would suffer life's various pitfalls—but only if they had overestimated that probability. In other words, if they had predicted that their likelihood of developing cancer was 40 percent, but learned that the lifetime risk is in fact 30 percent, they adjusted their estimate to a more reasonable 32 percent. But if they had underestimated the chance of falling victim to one of these incidents—saying they had a 10 percent risk of being robbed when in fact the chance is 20 percent—they basically stuck with their original guess. The scientists ruled out the possibility that people simply forgot the probabilities they were shown. “They remembered the data equally well regardless if it was better or worse than expected,” says neuroscientist Tali Sharot of the Wellcome Trust Centre for Neuroimaging, who led the study. “The difference was in whether they used the information to update their beliefs regarding their own likelihood of experiencing the negative events.”

Functional MRI measured the volunteers’ brain activity during all this and produced a remarkable finding. When people changed their probability estimate in light of better-than-expected information—for instance, your chance of becoming impotent is 30 percent, not the 60 percent you guessed—activity in the frontal lobes corresponded to what was needed to track the incoming data and adjust their estimate. The frontal lobes, the seat of higher-order cognitive functions such as selective attention and judgment, were processing the new information. But when reality was grimmer than people estimated—the chance of dying before age 90 is 60 percent, not 40 percent—the information-tracking and odds-calculating activity in the frontal regions of the extreme optimists was much weaker. (The extreme optimists were identified in advance by a personality questionnaire.)

Think of a toddler covering her ears and chanting, “Nyah, nyah, I can’t hear you!” to an adult reprimanding her. The necessary data processing was simply “not going on in the high optimists when they received negative information,” says Sharot. It seems that “we pick and choose the information that we listen to. The more optimistic we are, the less likely we are to be influenced by negative information about the future.”

Why did the frontal lobes go on strike in the face of unwelcome information? Sharot and her colleagues are now studying whether the brain’s emotion regions are responsible. Numerous “inhibitory neurons”—those carrying the instructions, “don’t fire!”—run from the emotion centers to the reasoning areas, and there are hints that when people see data telling them they’re more likely to, say, get divorced than they realized, the emotions freak out and prevent the cognitive regions from dealing with the unwelcome information. Although the work has only started, says Sharot, “It seems that there are regions (also in the frontal lobe) inhibiting the activity needed to track negative information.”

Sharot is actually quite a fan of optimism. In her recent book, The Optimism Bias, she notes that optimists tend to earn more and live longer, among other benefits. “Believing that a goal is attainable motivates us to execute actions that will help us get closer to our dreams,” she says. “This is why optimists are more likely to succeed in academics, sports, and politics.” It’s when reasonable optimism tips into the foolish kind that the bill comes due.