"The brain finds unexpected pleasures more rewarding than expected ones, and it may have little to do with what people say they like." The scientists say their findings could lead to better understandings of addictions and other disorders. 

   The study was conducted by teams of physicians at Emory University in Atlanta and Baylor College of Medicine in Houston. They used brain scans to study how sequences of pleasurable sensations affected the brain's reward pathways -- nerve circuits that act as high-speed connections to the pleasure centers. 

   The volunteers had fruit juice and water squirted into their mouths in patterns that were either predictable or completely unpredictable. "We found the reward pathways responded much more strongly to the unexpectedness of stimuli instead of their pleasurable effects," says researcher Read Montague.