Scientists can now explain why the brain prefers one brand of soft drink to another

Oct 13 2004

A study involving 67 people showed no preference for either Coca-Cola® (Coke®) or Pepsi® when the drinks were administered anonymously, according to results published in the Oct. 14 issue of the journal Neuron. However, when told what they were drinking, roughly three-fourths preferred Coke. All 67 also submitted to brain scans.

“There’s a huge effect of the Coke label on brain activity related to the control of actions, the drudging up of memories, and things that involve self-image,” said Dr. Read Montague, director of the Brown Human Neuroimaging Lab at Baylor College of Medicine.

The BCM study, funded by the National Institute of Drug Abuse, is the first to analyze how cultural messages penetrate parts of the brain and influence personal preferences, and its results, Montague says, belie claims made during the “Pepsi Challenge” advertising campaign of the 1980s, in which taste testers purportedly chose Pepsi over Coke when they were not told what they were drinking.

“We live in a sea of cultural messages. Everybody has heard of Coke and Pepsi, they have messages, and, in the case of Coke, those messages have insinuated themselves in our nervous systems,” said Montague, the principal investigator of the study. “There is a response in the brain which leads to a behavioral effect – in this case, personal preference – regarding these beverages.”

Coke and Pepsi were used not only because of their cultural familiarity but also because they consist primarily of sugar and water. Both ingredients are considered “primary reinforcers” that resonate in an area of the brain called the ventral putamen, which is involved in reward-related learning, or positive values attributed to activities like eating and drinking.

Functional magnetic resonance imaging allowed Montague to predict fairly accurately which people preferred Coke or Pepsi before they even took a sip.

“We were stunned by how easy this was,” Montague said. “I could tell what they were going to do by looking at their brain scans.”

“Neuromarketing,” an area of neuroscience that maps brain activity as it relates to social sciences like economics and ethics, has drawn criticism from some consumer rights activists who claim that neuromarketing research poses unethical risks and could lead to manipulative business strategies by corporations eager to market their products more effectively.

Montague counters that these critics misunderstand the nature of such research and that the Coke and Pepsi study actually empowers consumers by making them aware of their susceptibility to cultural messages and images.

“We are not trying to figure out how to market something better,” Montague said. “We want to be able to better understand how brains work so that we can hopefully cure more neurological disorders.”