UCLA

Cognitive psychologists and neuroscientists traditionally take advantage of tightly controlled experimental studies to make claims about how the mind and the brain work – we design tasks and conditions to isolate a single component and use the results to make conclusions. However, it is becoming increasingly clear that as we move to understand more complex, naturalistic cognition, we need to consider the integration of cognitive processes. This dissertation probes how the integration of processes involved in human memory can help us better understand behavior. The first chapter begins by providing an overview of three domains of memory that are subserved by multiple components – declarative memory, memory for faces, and working memory. Chapter 2 investigates the bidirectional interactions of episodic and semantic memory by employing a paired associate learning task with semantically related and unrelated word pairs that additionally manipulates whether the word pairs are learned through either active retrieval practice or passive restudying. This paradigm, along with a novel extension of a multi-arrangement task (Kriegeskorte & Mur, 2012) to index semantic space before and after learning, shows that prior knowledge asymmetrically reshapes semantic space to make cue words more predictive of target words and testing reduces potential interference by repelling moderately related lure pairs away from the to-be-learned pair in semantic space. Chapter 3 shifts to focus on face memory. In this chapter, we use a large battery of behavioral tasks to identify four latent cognitive processes – face perception, episodic long-term memory, general intelligence and working memory. We show that these factors linearly combine to predict performance on two measures of face memory, one of which we designed to be a more ecologically valid index of personal identity memory. We also identify two cognitive profiles that differentially use working memory and face perception to accomplish our face memory task, highlighting how individual differences in cognitive ability may impact how processes interact to support behavior. In Chapter 4, we sought to explain individual differences in working memory performance, working memory capacity (WMC), and psychiatric outcomes using a wide range of structural and functional MRI measures. Our results highlight how working memory performance and WMC may be predicted by different aspects of functional and structural MRI that reflect distinct underlying processes. Taken together, the findings presented in this dissertation underscore the complexity of cognition. Expanding how we study the mind and brain to take multiple processes of cognition into account will allow us to better characterize and understand complex, real-life behavior.