7. Project Summary/Abstract Alcohol misuse among emerging adults (age 18-25) is a major public health concern that results in acute and chronic consequences, such as blackouts, motor vehicle accidents, poorer career outcomes, disease, and death. Although many individuals ?mature out? of heavy drinking, the determinants of positive drinking trajectories are unknown. Further, longitudinal studies examining these determinants often do not include biological indicators, inherently creating a gap between neuroscientific and clinical inquiries into alcohol misuse. Thus, as an adjunct study to an already funded longitudinal R01 (R01AA024930-01; Multiple PIs MacKillop & Murphy), we will recruit heavy drinking emerging adults (N = 95) at their 8-month follow-up appointment to engage in a single electroencephalogram (EEG) session measuring two event-related potential components that theoretically represent reward processing. Participants will then continue participation in the parent R01 and will complete follow-up self-report sessions at 12- and 16-months. Data collected from the EEG session will be used to predict changes in alcohol misuse (alcohol consumption, alcohol-related problems, and alcohol use disorder) at the 4- and 8-month follow-ups (i.e., the 12 and 16-month parent study follow-ups). The aims of the proposed project are: 1) to integrate electrophysiological indices (P3 and RewP) of alcohol, nonalcohol, immediate, and delayed reward into the ongoing longitudinal study to compare with self-report behavioral economic variables already included (i.e., alcohol demand, delayed discounting, substance-related relative to substance-free reinforcement); and 2) to explore prospective relations between event-related potentials, behavioral economic variables, and alcohol misuse. The study employs two paradigms for eliciting event-related potentials of reward processing: 1) oddball task (repetitive ?common? stimulus presentation with dispersed ?uncommon? images, for eliciting reactivity during uncommon images) for both nonalcohol and alcohol cues (P3); and 2) a doors task (gambling task in which participants make a choice between two doors with either positive or negative feedback about reward outcome) for both immediate and delayed rewards (RewP). During the award period, the applicant will undergo advanced training in alcohol misuse, electrophysiology, behavioral economics, neuroeconomics, and longitudinal data analysis, preparing the applicant for a career as an expert in behavioral economics and electrophysiology. This study provides a translational understanding of reward processing, an important mechanism related to alcohol-related pathology (NIAAA strategic plan Goal 1), and evaluates multiple indices of reward processing as predictors of alcohol misuse. This investigation may establish an electrophysiological biomarker of diminished alcohol-free reward response with the potential to improve the diagnosis and the prediction of the trajectory of alcohol use disorder (NIAAA strategic plan Goal 2). Results from this project will inform future efforts in behavioral economic theory and intervention development.