Now, I have the science to prove it:
Montague had his subjects take the Pepsi Challenge while he watched their neural activity with a functional MRI machine, which tracks blood flow to different regions of the brain. Without knowing what they were drinking, about half of them said they preferred Pepsi. But once Montague told them which samples were Coke, three-fourths said that drink tasted better, and their brain activity changed too. Coke “lit up” the medial prefrontal cortex — a part of the brain that controls higher thinking. Montague’s hunch was that the brain was recalling images and ideas from commercials, and the brand was overriding the actual quality of the product.