UC Riverside

The human mind represents the world by temporarily holding information in working memory that constructs an internal map of the external environment. This active information storage system does not simply produce veridical recordings of the moment-by-moment experience. Instead, it is rather a reconstructive process that possesses inherent, manifold limitations. A central question is thus how the erroneous nature of working memory can be best characterized. In this dissertation, I use behavioral and computational modeling methods to propose a shift in the central tendency of the internal representation as a psychologically valid aspect of working memory that is independent of other known limits such as capacity or resolution. In Chapter 1, I review general working memory literature and our current understanding of the representational limits, then introduce a shift component as another source of working memory quality. In Chapter 2, I present computational modeling work with a set of data simulations and parameter recovery. I elucidate the necessity of the shift parameter in explaining working memory errors and how robust modeling of shift can be achieved using a hierarchical Bayesian approach. I then present a collection of empirical studies in Chapters 3 and 4 that experimentally show how this shift parameter can be utilized in theoretically important hypothesis testing. In Chapter 5, I extended the idea to mouse cursor trajectory data where the curved trajectory pattern can be operationalized as a moment-by-moment readout of representational shifts. In Chapters 6, I present an original empirical study that shows how the trajectory-based analyses of representational shift provide precise evidence crucial for constraining competing theoretical debates. Together, this dissertation provides a theoretical framework and a quantitative model to validate memory accuracy (i.e., representational appearance), manifested as the central tendency of the recall error distribution over sensory feature space, as another major source of working memory quality.