Why You Really Do Prefer Coke or Pepsi?  

Guess what? Your passionate preference for Coke or Pepsi is in your brain, not just your taste buds.

Baylor University researchers gave 67 volunteers taste tests of Coke and Pepsi, and brain scans showed that when they knew what they were drinking it not only affected their preference, but also activated memory-related brain regions that recall cultural influences.

Academic-speak translation: Product branding and advertising work.
Lead study author Samuel McClure, who has left Baylor and is now a professor at Princeton University, said in a news release announcing the study findings that our choice for Coke or Pepsi is affected by our perception because "there are visual images and marketing messages that have insinuated themselves into the nervous systems of humans that consume the drinks." That's right. Science says advertising has worked its way into our nervous systems. While scientists have long suspected that cultural messages do have an impact on taste perception, they did not know until now that there was a neurological component as well.

The team chose a Coke vs. Pepsi test for two reasons. First, there is a growing obesity crisis in the United States, and sugary soft drinks are one of the leading causes. In addition, even though Coke and Pepsi are nearly identical chemically and physically, people often have a very strong preference for one or the other, making them ideal for a rigorous scientific study.

Interestingly, the researchers found there was no influence of brand knowledge for Pepsi, but when it came to Coke, there was a dramatic effect of the Coke label on behavioral preference. The brand knowledge of Coke influenced their preference and activated specific areas of the brain, including the dorsolateral prefrontal cortex and the hippocampus, both of which are implicated in modifying behavior based on emotion.

The conclusion: Two separate brain systems in the prefrontal cortex--one involving taste and one recalling cultural influence--interact to determine our preferences. And you thought you just liked the taste!