October 19, 2004 If Your Brain Has a 'Buy Button,' What Pushes It? By SANDRA BLAKESLEE nowing what brand you are buying can influence your preferences by commandeering brain circuits involved with memory, decision making and self-image, researchers have found. When researchers monitored brain scans of 67 people who were given a blind taste test of Coca-Cola and Pepsi, each soft drink lit up the brain's reward system, and the participants were evenly split as to which drink they preferred. But when the same people were told what they were drinking, activity in a different set of brain regions linked...