In a building across the campus from Jill Austin’s office at the Vanderbilt University Medical Center is a machine that is a marketer’s dream. It’s somewhat nondescript visually, but the information it can produce makes most data-gathering methods look archaic.
The machine is a functional magnetic resonance imaging scanner, or fMRI for short. It scans the brain as people answer questions, giving an honest look at their response before the answers become filtered by....