A few years ago, scientists one upped the Pepsi challenge. Unlike the original taste test, there were no camera crews or looks of staged surprise from loyalists of ‘the other’ leading cola. Instead, volunteers rested inside an MRI scanner and tasted sips of Coke and Pepsi delivered through plastic tubes. Some trials involved rating beverage preference by taste alone. On other trials, the brand labels were also provided. To reveal the effect of branding on preference, some of the cola samples were intentionally mislabeled.

The verdict? For most people, Pepsi labeled as Coke tastes better than Pepsi labeled as Pepsi.

Evidently, advertising works, and as this experiment went on to further suggest, you can in some sense ‘see’ a brand at work in the brain as it alters or supplements sensory processing.

While fascinating, these kinds of data probably aren’t exciting to someone peddling a second-rate product. What good is seeing the neural correlate of your lousy brand, especially if you’ve already invested a lot in it?

Naturally, what marketers would really want to do is run this process in reverse. That is, watch a brain respond to something yet untested, and predict its future success. Is there some kind of neural signature that indicates what will ultimately become popular and obsessed over, and what will flop?

For now, no. However, a recent study by a pair of scientists shows that the idea isn’t entirely implausible. Working from the departments of Economics and Neuropolicy at Emory University, Gregory Berns and Sara Moore found a surprising, if modest, correlation between brain activity while experiencing a new product and that product’s cultural popularity years later.

Instead of studying soft drinks, Berns and Moore studied music preferences in adolescents. In 2006, they placed 32 children, aged 12 to 18, in an MRI scanner and had them listen to a wide variety of short song clips downloaded from MySpace.com. The scientists took scans of song-related activity in the children’s brains, and had the children report how likable each song was. After identifying brain areas whose activity was correlated with song likability, the scientists patiently sat on the data for about 3 years.

During that time, the songs did what songs will do. A tiny percentage became extremely popular, a handful more became somewhat popular, and the overwhelming majority went nowhere. After tallying the sales information for each song, the scientists essentially took a shot in the dark. They re-examined brain areas associated with song likability years ago, and asked if activity in those areas predicted a song’s eventual success.

For one area -- the nucleus accumbens - the answer was yes. Though it certainly didn’t distinguish between hits and duds with dead-on accuracy, more activity in the accumbens was loosely predictive of higher sales.

This study wasn’t designed to test any specific idea about how the nucleus accumbens might do this. However, a good deal of other work has implicated this structure in reward processing and the subjective experience of pleasure, including that derived from music. The nucleus accumbens is one of the key subcortical structures of the brain’s mesolimbic pathway, a major subsystem bearing the neurotransmitter dopamine. Given the rich body of work linking dopamine to reward processing and valuation, it’s not surprising to see the nucleus accumbens implicated in the present study.

It’s important to be skeptical of attempts to simplify these kinds of findings as evidence for the brain’s “buy button”, or “approval meter.” Dopaminergic brain systems evolved to help their owners anticipate, forage, and act in the face of uncertainty, not predict trends in teenybopper stardom. Still, this study is among the most compelling in the nascent field of neuromarketing. It also helps to address critics of one of the field’s early eyebrow raising pledges: that a consumer’s brain might provide better information about future purchases than the consumer.

Similar to what others have seen, the authors of the teen song study found that experimental subjects were not skilled at predicting which songs would go on to become popular. This leads to something of a puzzle.  How can a noisy, indirect, and heavily processed signal from the brain tell you more than asking someone “hey, do you like that song?”

The reasons are unclear, but there are many interesting possibilities. Of course, there’s always a chance this is due to some kind of methodological shortcoming. Maybe the questionnaires on song likability were poorly worded, or otherwise insufficient to elicit good guesses about a song’s future popularity. Another possibility is that we’re a bit dishonest with ourselves. When asked which songs we most like, we might bow to perceived expectations, for example, downplaying our embarrassing inner rapture over Justin Bieber, or overstating our enjoyment of Miles Davis.

Alternatively, the problem may not be willful dishonesty, but rather simple ignorance about what goes on in our brains. There could just be a complex array of so-called ‘metacognitive’ processes intervening between the raw, visceral assessment of a song and our report of whether we like it. Enjoying a song in the moment -- which the study examined – may be relatively simple but hidden to self interrogation. By contrast, making a case, even implicitly, that you like or dislike a song probably makes additional demands on cognitive systems for memory (does this sound like other things I like?) and forecasting (is this a cool, potentially popular riff, or just weird?). For someone in the business of predicting a hit, all of this ‘thinking about liking’ may just be noise.

Which raises yet another, admittedly speculative, possibility. Perhaps songs or other pop culture ideas don’t necessarily become popular because they’re likable by some common, aesthetic criteria that can be easily articulated. It may be that what was observed in the brain scans collected by Bern and Moore wasn’t so much a correlate of pleasure, or intrigue, but something more like ‘catchiness.’ If that’s the case, we may have been given a glimpse of new ideas and memes, just starting to take hold in the brain.

Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook, a Pulitzer prize-winning journalist at the Boston Globe. He can be reached at garethideas AT gmail.com or Twitter @garethideas.