Human behavior is commonly understood as emerging from a struggle between will and habit, i.e., between “intentional” processes driven by the current goal and “automatic” processes driven by available stimuli. This scenario suggests that it is mainly the goal-related processes that render behavior adaptive. Based on a novel theoretical framework (the Metacontrol State Model, combined with the Theory of Event Coding) that is motivated by recent behavioral and neuroscientific observations, I suggest an alternative view and argue that people can control the relative contributions of goal-driven and stimulus-driven processes to decision-making and action selection. In particular, people regulate the interaction between these processes by determining the ratio between (goal) persistence and flexi-bility, depending on task, situation, and personal experience—a process that I refer to as “metacontrol”. The project aims to identify and trace individual “metacontrol policies” (biases towards persistence or flexibility) and task- and condition-specific changes therein by means of behavioral, computational, and neuroscientific techniques, and by using virtual-reality methods. I shall study, account for, and try predicting individual differences in the choice and implementation of such policies, identify and explain the cognitive and social consequences of adopting a particular policy, and investigate whether and how people can adopt meta¬control policies from others—either intentionally or automati-cally. I shall also study whether and to what degree people use situational cues to automatize the implementation of suitable policies, and whether often-used, highly practiced policies can become chron-ified and turn into a trait-like processing style, as suggested by cultural studies.