When he isn't pondering the inner workings of the mind, Read Montague, a 43-year-old neuroscientist at Baylor College of Medicine, has been known to contemplate the other mysteries of life: for instance, the Pepsi Challenge. In the series of TV commercials from the 70's and 80's that pitted Coke against Pepsi in a blind taste test, Pepsi was usually the winner. So why, Montague asked himself not long ago, did Coke appeal so strongly to so many people if it didn't taste any better?
Over several months this past summer, Montague set to work looking for a scientifically convincing answer. He assembled a group of test subjects and, while monitoring their brain activity with an M.R.I. machine, recreated the Pepsi Challenge. His results confirmed those of the TV campaign: Pepsi tended to produce a stronger response than Coke in the brain's ventral putamen, a region thought to process feelings of reward. (Monkeys, for instance, exhibit activity in the ventral putamen when they receive food for completing a task.) Indeed, in people who preferred Pepsi, the ventral putamen was five times as active when drinking Pepsi than that of Coke fans when drinking Coke.
In the real world, of course, taste is not everything. So Montague tried to gauge the appeal of Coke's image, its ''brand influence,'' by repeating the experiment with a small variation: this time, he announced which of the sample tastes were Coke. The outcome was remarkable: almost all the subjects said they preferred Coke. What's more, the brain activity of the subjects was now different. There was also activity in the medial prefrontal cortex, an area of the brain that scientists say governs high-level cognitive powers. Apparently, the subjects were meditating in a more sophisticated way on the taste of Coke, allowing memories and other impressions of the drink -- in a word, its brand -- to shape their preference.
Pepsi, crucially, couldn't achieve the same effect. When Montague reversed the situation, announcing which tastes were of Pepsi, far fewer of the subjects said they preferred Pepsi. Montague was impressed: he had demonstrated, with a fair degree of neuroscientific precision, the special power of Coke's brand to override our taste buds.
Measuring brand influence might seem like an unusual activity for a neuroscientist, but Montague is just one of a growing breed of researchers who are applying the methods of the neurology lab to the questions of the advertising world. Some of these researchers, like Montague, are purely academic in focus, studying the consumer mind out of intellectual curiosity, with no corporate support. Increasingly, though, there are others -- like several of the researchers at the Mind of the Market Laboratory at Harvard Business School -- who work as full-fledged ''neuromarketers,'' conducting brain research with the help of corporate financing and sharing their results with their sponsors. This summer, when it opened its doors for business, the BrightHouse Institute for Thought Sciences in Atlanta became the first neuromarketing firm to boast a Fortune 500 consumer-products company as a client. (The client's identity is currently a secret.) The institute will scan the brains of a representative sample of its client's prospective customers, assess their reactions to the company's products and advertising and tweak the corporate image accordingly.
Not long ago, M.R.I. machines were used solely for medical purposes, like diagnosing strokes or discovering tumors. But neuroscience has reached a sort of cocky adolescence; it has become routine to read about researchers tackling every subject under the sun, placing test subjects in M.R.I. machines and analyzing their brain activity as they do everything from making moral choices to praying to appreciating beauty. Paul C. Lauterbur, a chemist who shared this year's Nobel Prize in medicine for his contribution in the early 70's to the invention of the M.R.I. machine, notes how novel the uses of his invention have become. ''Things are getting a lot more subtle than we'd ever thought,'' he says. It seems only natural that the commercial world has finally caught on. ''You don't have to be a genius to say, 'My God, if you combine making the can red with making it less sweet, you can measure this in a scanner and see the result,''' Montague says. ''If I were Pepsi, I'd go in there and I'd start scanning people.''