For example, they said, if a person is looking for a child lost in a crowd, some brain areas usually dedicated to recognizing other objects, or even areas engaged in abstract thought, will shift focus and join the search.
To turn into a highly focused child-finder, the brain temporarily redirects resources it uses for other mental tasks, scientists at the University of California, Berkeley, reported.
"Our results show that our brains are much more dynamic than previously thought, rapidly reallocating resources based on behavioral demands, and optimizing our performance by increasing the precision with which we can perform relevant tasks," neuroscience postdoctoral researcher Tolga Cukur said.
The findings shed light on how people shift attention to challenging tasks, he said.
"As you plan your day at work, for example, more of the brain is devoted to processing time, tasks, goals and rewards, [but] as you search for your cat, more of the brain becomes involved in recognition of animals," he said.
The study can help explain why we find it difficult to concentrate on more than one task at a time, he said, and may provide greater insight into neurobehavioral and attention deficit disorders.