Knowing the brand of a soft drink can influence our perception of what it tastes like, scientists say the results of tests show.
Branding appeared to alter taste
They asked volunteers to do the famous Pepsi versus Coke taste challenge.
Brain scans showed when the volunteers knew which brand they were tasting, the parts of the brain involved with recalling memories were activated.
The US Baylor College of Medicine team told Neuron this showed how branding could influence behavioural choice.
The researchers said they decided to use Coke and Pepsi because even though the two drinks are nearly identical chemically and physically, people often strongly favour one over the other.
They asked 67 volunteers to taste the drinks in a series of experiments while undergoing brain scans.
When the volunteers were unaware which beverage they were drinking, they expressed no preference for one over the other.
However, when they were given visual clues to the brand they were drinking, the volunteers expressed a definite preference.
When the researchers looked at the brain scan results, they found brain activity patterns appeared to explain what was happening when the volunteers were making these decisions.
Lead researcher Dr Read Montague said: "There is a response in the brain which leads to a behavioural effect - in this case, personal preference - regarding these beverages."
Knowledge of the brand influenced preference and activated brain areas including the dorsolateral prefrontal cortex and the hippocampus.
These areas are involved in recalling cultural influences and modifying behaviour based on emotion and mood.
Dr Montague said: "We live in a sea of cultural images.
"Everybody has heard of Coke and Pepsi, they have messages, and...those messages have insinuated themselves in our nervous system."
But he emphasised that he was not trying to figure out how to market something better.
"We want to be able to better understand how brains work so that we can hopefully cure more neurological disorders," he said.
Dr John O'Doherty, a research scientist at University College London's Functional Imaging Lab, said it was widely known that perception of the taste or smell of a food item can be influenced by other information such as the images, textures or sounds associated with that
"Advertisers have long known that you can influence people's decisions or preferences by providing different contextual information.
"One of the ways is by associating a brand with other pleasant, rewarding things.
"What this study shows is how this preference is modulated by contextual information in the brain, which is a novel finding."