ABSTRACT PAR-18-30 “Development and Optimization of Tasks and Measures for Functional Domains of Behavior” encourages research projects that will develop and optimize new or existing tasks and measures for the Research Domain Criteria (RDoC). This call stems from workgroups of the National Advisory Mental Health Council that identified significant gaps in the RDoC measurement toolkit. In the negative valence systems (NVS) domain, one priority area is the need for behavioral paradigms for identifying areas of overlap and distinction between NVS, which motivate defensive avoidance behaviors, and positive valence systems (PVS), which motivate reward-approach behaviors. We contend that approach-avoidance (AP-AV) paradigms offer a promising solution. AP-AV tasks are essentially behavioral approach tests that enable assessment of overt behavioral responses to acute threats. The aims of this proposal are to demonstrate the (1) psychometric adequacy (test-retest reliability) and (2) diagnostic/predictive validity of a user-friendly instructed AP-AV-task we’ve developed for assessing psychosocial dysfunction associated with anxiety, depression, psychosis, and other conditions. Our aims build upon extensive preliminary research in our lab devoted to optimizing task parameters, measures and administration. This work has the potential to yield an easy-to-use and widely disseminable AP-AV task for identifying areas of overlap and distinction between NVS and PVS, as well as a general AP-AV methodology that is adaptable for assessing overt behavioral responses to acute threats. To achieve these aims, we will recruit three matched groups of adults (healthy, elevated social anxiety, and elevated social anhedonia). Inclusion of groups with anxiety and anhedonia are necessary to assess diagnostic and predictive validity. Participants will complete standardized clinical assessments and complete the instructed AP-AV task multiple times during two neuroimaging sessions, separated by 10-14 days. Between imaging sessions, ecological momentary assessments (EMA) will capture mood, motivational level, frequency of real-life approach/avoidance, and emotional regulation strategy use. This research is theoretically significant because it highlights the relevance of theories of AP-AV motivation for research devoted to identifying areas of overlap and distinction between NVS and PVS. This research is methodologically innovative because it will produce a user-friendly AP-AV task with strong psychometric properties for use in behavioral (stand-alone) or neuroimaging research. Outcome data will also provide the necessary empirical foundation for future investigations into the suitability of AP-AV tasks for use with individuals who vary widely in age, ability, and/or severity of disorder.