Project Summary/Abstract The present application lies at the intersection of NIMH Strategic Plan Strategy 3.1 (to identify and validate new targets for treatment development that underlie disease mechanisms) and NIA Goal D, Objectives D-1 (understand the role of cognition in everyday functioning) and D-3 (better distinguish individuals who are aging normally from those with MCI). We propose that self-awareness across multiple domains represents a critical and novel target that: 1) is impaired in MCI, 2) impacts daily functioning, and 3) may predict trajectories from healthy to MCI to Alzheimer’s Disease. The parent project examines self-awareness in severe mental illness and operationalizes it as Introspective Accuracy and Introspective Bias, with IA referring to the ability to evaluate one’s own skills and performance and IB relating to the directionality of introspective inaccuracies (under- vs. overestimation). In this supplement application, we propose to use these definitions to comprehensively examine self-awareness in MCI. Impaired self-awareness is well-documented in Alzheimer’s disease, and an inconclusive literature suggests that self-awareness may also be impaired in MCI. The identification of inaccurate self- assessment in MCI would have far-reaching implications for the validity and utility of subjective cognitive complaints, and thus, IA and IB are at the core of subjective assessment of cognition. However, a number of critical questions remain regarding the extent of IA/IB deficits in MCI, the impact of IA/IB on everyday functioning in this population, and how IA and IB relate to individual differences in psychosocial factors such as mood and activity. Given that diagnosis of MCI often relies on subjective cognitive complaints and that people typically only seek treatment when impairments are detected, a better understanding of the accuracy of self-assessments in MCI is necessary. By assessing IA and IB across the functionally-relevant domains of neurocognition, social cognition, and functional capacity, we will test the overarching hypotheses that IA and IB are impaired in MCI relative to normal aging and that these impairments span domains (Specific Aim 1), that IA and IB are critical determinants of everyday functioning (Specific Aim 2), and that within individuals, mood and activity levels will dynamically influence both the degree and direction of introspective deficits and vice versa (Specific Aim 3). Our study design will allow for the assessment of IA and IB at both inter- and intra-individual levels by utilizing Ecological Momentary Assessment (EMA) to obtain in vivo, longitudinal data on IA and IB. The findings of this project will demonstrate the feasibility and utility of examining IA and IB in MCI. The project will also provide pilot data that will be used in future grant submissions that will combine biological characterization of AD-risk (e.g., APOE ε4 status) with behavioral indicators of IA/IB to determine whether ...