Why do we sometimes rely on slow, deliberative, and effortful choices, while at other times we rely on fast, habitual, and reflexive choice? On one hand, making the best possible decision is effortful and time-consuming, but on the other hand, the benefits resulting from deliberative behavior may be small relative to its cost. My research investigates why we sometimes rely on slow and effortful choices, while at other times we rely on fast and reflexive choice. For example, how does an individual’s reliance upon reflective versus reflexive choice vary situationally based on factors like availability of cognitive resources, stress, time pressure, or perceived costs and benefits? Why might individuals differ, dispositionally, in their reliance upon reflective versus reflexive choices? To answer these questions, we use a combination of computational, behavioral, and psychophysiological, and neuroimaging techniques.