WEDNESDAY, Dec. 24, 2008 (HealthDay News) -- A sports car, a diamond ring, ice cream -- some things may make the human brain "pop."
So finds new research showing that neural vision systems get turned on by expensive or "rewarding" objects, even before people realize they're excited.
When you know that an object has been rewarding in the past, "your brain is representing them differently," said John Serences, a professor of psychology at the University of California, San Diego. "That may mean that you're seeing things that are of high value more clearly or sharply."
The research suggests that even the parts of the brain that handle the very beginning of the vision-processing system can tell whether something is valuable and should be flagged, Serences said.
In the new study, published in the Dec. 26 issue of the journal Neuron, Serences scanned the brains of 14 college students using fMRI technology, which allows scientists to detect activity in the brain.
The subjects played a game in which they were told to choose between red and green targets. They got 10 cents -- up to a total of $10 -- each time they chose certain targets.
The students learned that some targets would reward them and some wouldn't, and the fMRI imaging showed that their brains reacted differently to targets that had been monetarily rewarding in the past.
"One of the implications is that your brain is signaling to you that the items have been previously rewarded," Serences said. "Our brain is treating those things differently than those that have been associated with no rewards or those that have been associated with fewer rewards than in the past."
In an unusual finding, the researchers found that the brains of the subjects seemed to remember which targets were more rewarding even if the subjects themselves actually forgot.
Is this a uniquely human ability? Serences said that isn't clear, although he wouldn't be surprised if other animals have the same skills. "Monkeys would probably have the same thing, and I wouldn't be surprised if a dog did, too," he said.
Plenty of factors go into decisions about things that we think are rewarding, of course, and the instant judgments of our brains may play just one part in a wider picture. For example, Serences said, our choices about eating ice cream or vegetables may depend on things like whether we're on a diet.
But the findings suggest that there may be an ingrained bias in the human brain, he said. "Right from the start, you might be predisposed to the ice cream, because your brain is more predisposed to it than the vegetables."
Learn about neuroeconomics, the study of how our brains make decisions, at Cal Tech.