01/07/2013 07:25 pm ET Updated Mar 09, 2013

All That Glitters Ain't So Great: How Your Brain Rates the Stuff You Buy

Gold, the ancient Egyptians said, was the skin of the gods -- but their bones were made of silver. And for thousands of years, royal scribes ranked silver jewelry as more valuable than gold, reversing the order only when cultural trends shifted in gold's favor. Silver's worth, in short, was never divinely ordained; in one age or another, its price depends on human desire.

Over the years that delicate balance of availability, desirability and prestige (what we now know as "supply and demand") has played havoc with the market values of the foods we eat, the cars we drive and the adornments we wear. In colonial New England, lobster was considered so revolting that prisons were forbidden from serving it more than once a week. Before the 1970s most Americans thought of Japanese cars as some of the cheapest junk heaps on the lot. And, perhaps most infamously, diamonds had dropped firmly into the class of "budget" gemstones back in 1938, when the advertising firm N.W. Ayer & Son began bombarding luxury magazines with ads for De Beers diamond engagement rings.

Like it or not, even the most independently minded of us tend to build our lifestyles around our perceptions of what others are eating, driving and wearing, even if we do so by rebelling against those cultural norms. Companies like Google and Apple have built empires on cultural consensus, and they're only centerpoints of an ever-growing ecosystem.

Take, as one more modern example, National Positions, a search engine optimization (SEO) company I encountered as I was researching marketing techniques. Though I haven't personally worked with this company, I can tell a few things about them from their website and other press: Like other SEO companies, they hang promises of profits on their influence over customers' search results. They boast of an existing roster of high-status clients; in other words, they apply status-centric marketing techniques in a business-to-business context. And they mention a small-scale startup period, effectively grounding their story in our culture's by-the-bootstraps mythology of success. In short, National Positions pushes all the buttons I touched on above, and that's going to become important to this story in just a moment.

See, in some senses, we've come a long way since the days of bartering grain for gold trinkets. But in many other, more primal ways, the machinery at work has always been the same. Case in point: a new study that's worked out why some of us are more confident in our purchases than others.

The research, published in the journal Nature Neuroscience, examined the age-old idea that those of us most in touch with our true desires tend to be the happiest with what we buy. A team led by Benedetto De Martino and Ray Dolan assembled a party of hungry volunteers to tackle some food-related quizzes. First, the participants filled out a questionnaire on how much they'd be willing to pay for various tasty foods. Then they filled out a second questionnaire, rating their confidence with each choice they'd made. Throughout both quizzes, the researchers were carefully watching the subjects' brain activity through an fMRI scanner.

In the brains of volunteers who were most confident in their choices, the team found unusually strong collaboration between a brain area known as the ventromedial prefrontal cortex (vmPFC), which we know is involved in processing value and risk, and an adjacent area called the rostrolateral prefrontal cortex (RLPFC), which helps us rank our immediate goals. In other words, the clearer the communication between a hungry participant's vmPFC and RLPFC, the more consistent and confident that person's desires were.

What surprised the researchers wasn't finding evidence of value computation in the vmPFC; we've known about that for years. But discovering that the vmPFC is also so closely linked with value judgments, and that those judgments depend on the clarity of communication between the vmPFC and RLPFC, is already inspiring scientists to probe deeper into these prefrontal mechanisms of confidence.

And for the rest of us who'd just like to get more in touch with our desires, this research lays out a clear path: Reinforcement. The more we give our value-computation connections a workout, the clearer their communication will be. What those ancient Egyptian pharaohs and diamond marketers knew is also what a company like National Positions knows: Give clients and customers a sense of belonging, especially to an elite group, and they'll do most of the legwork for you. But with a little practice at "listening in" on what you really want (and need) to buy, you'll figure out your own ways to stay ahead of the market.