Stimulating Confidence

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If you wear glasses, you know that sinking feeling. In the eye doctor's office, the exam starts easily enough, and you confidently reel off the letters in the first few lines of the vision chart. But as the letters shrink in size, you start to squint and hesitate, until finally, you are stumped by a smudge in the corner. Is that a P? Or an F? Or something else entirely?

You guess "F," but at that point you have zero confidence. With each line, your certainty dwindled until you were cornered into taking a shot in the dark.

Confidence rises and falls as we make decisions throughout our day, like an invisible sure-o-meter. Stocks or bonds? Right or left? Paper or plastic?

But what exactly is this feeling of confidence?

Scientists have recently reported tapping into this feeling in rats. A new study published in the journal Nature found a signal in the brain related to confidence, and it shows that the complex process of decision-making is not beyond science's grasp.

Sniff test: Goats or grass?

For the scientists to study confidence, the rats first had to be trained to make decisions. To accomplish this, the researchers capitalized on the rodents' superior sense of smell. They presented rats with a smell that was a mixture of two pure odors: one that smelled like goats, and the other like freshly mowed grass. The rats were tasked with identifying which smell was the stronger one in the mix: goats or grass? When correct, they received a small reward.

Like the eye exam, the sniff test varied in difficulty. For smells dominated by the goat scent, rats usually correctly reported goat as the stronger. But as more of the grassy scent was mixed in, they started to make mistakes. For example, when the mixture consisted of 56 percent goat and 44 percent grass, the rats got it right only about half the time—not much better than guessing—and, the researchers surmise, showed they were experiencing a crisis of confidence.

The scientists listened in on the brain's neuronal activity as the rats made their decisions. In one part of the brain, called the orbitofrontal cortex, they found that the electronic chatter of certain neurons increased for the difficult sniff tests. While the rats waited to see if their choice was correct, their neurons became more active, firing vigorously. In the easier tests, however, these same neurons went quiet. With this sliding scale of activity, these orbitofrontal neurons seemed to give a readout of high or low confidence.

This is surprising because confidence has been presumed to involve something deeper, like self-awareness, which rats aren't thought to possess. This research now suggests that confidence—either high or low—is a common byproduct of decision-making, even in rats.

In an eerie twist, some neurons fired even more vigorously after a rat made a wrong choice, but before the rat was told it was wrong—kind of an "oops" signal. This suggests that some neurons in the brain "know" the right answer, but that ultimately they could not sway the final decision. Maybe this is why guessing is sometimes a useful strategy in multiple-choice exams like the SAT: Our intuition may try to tune into the quieter voices of the neurons that know the answer.

The psychology of confidence

In fact, cool logic does not reign as we make even simple decisions, and a swirl of signals including emotions, desires and experience impact a decision and our confidence in it.

The decision confidence described in the rats above might be akin to "attitude certainty" studied by psychologists. Attitude certainty measures the confidence a person has in his or her beliefs, positions or opinions about something.

Zakary Tormala, Ph.D., an expert in attitude certainty at Stanford, points out that this is different from self-confidence, but definitely related. In fact, his research finds that one way to become more self-confident is to cultivate attitude certainty.

And attitude certainty is definitely malleable. "There's a long list of variables," of what influences attitude certainty, Tormala says. For example, he says attitude certainty is higher when people think others share their attitude, or when people repeat their attitude over and over, or when people think they have thought a lot about the attitude. So creating a kind of echo chamber—thinking and talking about your position with like-minded people—could result in increased confidence, both about an attitude and about yourself.

Surprisingly, mixing with people who have different opinions can also cement a person's original position. Tormala finds that attitude certainty is strengthened when a person fends off persuasion. For example, "Someone might become more certain of their favorable attitude toward Barack Obama if they perceive that they have handily counter-argued a pro-McCain ad," he says.

So even in the face of differing positions on something, we seem programmed for certainty.

"We like to be certain of our beliefs, attitudes, and decisions and we'll expend considerable effort to achieve that feeling when it's missing," says Tormala.

Moving toward conviction

Whether locating a confidence signal in the rat brain will eventually help us improve our decisions is unknown, but the new study lays the groundwork.

For example, it will be interesting to see if manipulating confidence signals (by artificially driving these neurons to fire more or less frequently) will affect choices. Or whether some of Tormala's attitude-certainty variables will also influence the strength of the confidence signals. Research along these lines may reveal how we go from a mere hunch to a conviction we are willing to die for.

The key is now we know where to look.

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After spending 15 years in the lab doing her own neuroscience research, Michele Solis is now putting her Ph.D. to work as a science writer. Her work covers a variety of topics including autism, linguistics, and animal communication. She contributes regularly to the Autism Speaks, Simons Foundation, and Crosscut Web sites.