The brain has a learning system devoted to guiding people through routine, or habitual, behaviors, as well as a separate goal-directed system for actions undertaken only after careful consideration of consequences, they said.
Scientists at the California Institute of Technology are reporting that for the first time they've pinpointed areas of the brain -- the inferior lateral prefrontal cortex and frontopolar cortex -- that seem to serve as an "arbitrator" between the two decision-making systems.
Those brain areas weigh the reliability of the predictions each of those systems makes and then allocates control accordingly, principle investigator John O'Doherty said.
Understanding the location of the arbitrator and how it works may eventually lead to better treatment for brain disorders, such as drug addiction, and psychiatric disorders such as obsessive-compulsive disorder, he said.
"Now that we have worked out where the arbitrator is located, if we can find a way of altering activity in this area, we might be able to push an individual back toward goal-directed control and away from habitual control," O'Doherty, a professor of psychology, said.
The arbitrator ensures that the system making the most reliable predictions at any moment exerts the greatest degree of control over behavior, the researchers said.
"What we're showing is the existence of higher-level control in the human brain," Sang Wan Lee, study lead author and a postdoctoral scholar in neuroscience, said. "The arbitrator is basically making decisions about decisions."