People Find More Pleasure in Surprise Than Sensation

Most everyone likes the unexpected--those departures from the routine that lend a little spice to our lives. Now, a study suggests that people derive more pleasure from surprises than they do from other sensations and that addicts may simply be novelty junkies who crave constant stimulation.

Researchers at Baylor College of Medicine in Houston and at Atlanta’s Emory University tested 24 subjects, who were hooked up to magnetic resonance imaging machines to measure changes in their brain activity. Then, a computer-controlled device squirted either tropical fruit punch or water into their mouths. The patterns of juice and water squirts were either predictable or done in a random sequence.

Scientists figured the brain would register the strongest responses to the juice. But what triggered the biggest reaction was the unpredictable stimulation. “The pleasure centers of the brain lit up like Christmas trees, as if they were getting a hit of cocaine,” says P. Read Montague, a study coauthor and director of the Center for Theoretical Neuroscience at Baylor College of Medicine. So it’s not the pleasurable sensation itself--that squirt of tasty juice or refreshing water--that elicits a reaction. It’s the element of surprise.

These findings also may help answer a question that has long puzzled addiction experts, namely why people continue destructive behaviors, such as smoking crack or gambling, after they stop getting any pleasure from the activity. “People throw away fabulous jobs and comfortable lives to feed their habits long after the thrill of a drug has worn off,” says Montague. “But the unexpectedness itself, the excitement of doing something out of the ordinary, may be the reward that stimulates the pleasure pathways in their brain, not the drug or behavior.”