A study conducted by the Baylor College of Medicine in Houston into the preference for Coke versus Pepsi found Coke is preferred only because of its cultural brand iconography and that there is no perceived difference in taste between the two when tasted blind.
In the study, when asked to taste the two soft drinks blind, participants showed no preference. However, when the participants were shown company logos before they drank, the Coke label, the more famous of the two, had a dramatic impact: three-quarters of the tasters declared they preferred Coke. Perhaps branding does work. Afterall, it was Coke that got us all to believe Santa wears red.