A hallmark of human intelligence is the ability to efficiently adapt to uncertain, changing and open-ended environments. In such environments, efficient adaptive behavior often requires considering multiple alternative behavioral strategies, adjusting them, and possibly inventing new ones. These reasoning, learning and creative abilities involve the frontal lobes, which are especially well developed in humans compared to other primates. However, how the frontal function decides to create new strategies and how multiple strategies can be monitored concurrently remain largely unknown.