Decision making is ubiquitous, and the ability to develop the knowledge about the animal’s environment from experience and use this knowledge to produce a series of actions that will maximize the overall reward is essential for survival. Lee’s laboratory focuses on the role of the prefrontal cortex and the basal ganglia in evaluating the outcomes of the animal’s previous choices and incorporating this information to improve the animal’s decision-making strategies. His research is highly inter-disciplinary and capitalizes on the insights from formal theories of economics and reinforcement learning as well as computational neuroscience of neural coding and behavioral studies of decision making. His laboratory also develops novel behavioral paradigms that can probe the core processes of decision making. Combined with the use of multi-electrode recording systems, this research seeks to unravel the biological basis of willful actions.