The brain can handle two tasks by distributing them between the two hemispheres of the brain, assuming it perceives a worthy reward for doing so, but with large dual-task costs, researchers at the French National Institute for Health and Medical Research have found.

The study also explains why people tend to prefer binary options, such as yes-or-no questions and if-then statements: the frontopolar cortex (which organizes pending goals while the brain completes another task) cannot keep track of more than two goals/tasks at the same time.