Experts excel at remembering items from their specific domain of expertise. For example, a car expert is more likely than a novice to remember what models of cars he passed on his way to work. The mechanisms underlying these abilities are the foundation of performance in everyday life when, for example, a grocery cashier can readily discriminate different types of apples and remember the pricing code associated with each. Most of us experience the phenomenon of perceptual expertise with faces, a domain akin to expertise with other visual stimuli. We are all face experts, but mostly for faces that share ou own racial background, because we have less experience identifying faces from other races. Although the memory enhancing effects of expertise are well known, the underlying cognitive and neural processes are not. The proposed project will elucidate the mechanisms that lead to expertise-related facilitations in memory encoding (i.e., learning) and retrieval. It will also idetify the neural markers of brain activity that reflect facilitations in memory encoding and retrieval, which can be achieved by long-term perceptual and semantic learning as seen in perceptual expertise. The project will in addition examine the fine-tuning of perceptual processes that is often associated with expertise by investigating how and when facilitations in perception and memory develop during the initial stages of becoming an expert. This research will also determine whether learning processes in episodic memory causally influence learning processes in the perceptual system. To achieve these goals, the brain activity of subjects who vary widely in their level of expertise will be recorded with event-related potentials while subjecs engage in behavioral tasks. With this approach, associations can be established between behavioral improvements and changes in the neural processes of perception, memory encoding, and memory retrieval. In addition, training tasks will be used to simulate the initial stages of becoming an expert. Finally, the drug midazolam will be used to simulate anterograde amnesia to gain a better understanding of how amnesia affects expert memory and expertise learning. Studying perceptual expertise, which usually develops over the course of many years, will provide a framework for investigating the mechanisms of long-term learning and the long-term plasticity of the human perceptual and memory systems. This project will advance our understanding of the sub-processes of human memory encoding, retrieval, perception, and their interactions. This basic research will deepen our knowledge of human learning and memory, a vital undertaking for developing interventions for individuals whose memory has been compromised by aging, mental disease, learning disabilities, developmental disorders, or injury. This project will also facilitate the future development of treatments that enable people to maintain or return to employment after having suffered memory problems because all people are experts in some domain, most often in their profession.