Understanding the Cognitive and Neurobiological Systems Involved in Categorization Behaviour

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The primary goal of my work is to develop a comprehensive theory of how categories are learned and how conceptual knowledge is utilized. Classification involves perceiving an object, activating memory representations, assessing similarity to these representations, and making a decision. Some theories have focused on the nature of the representations and there is evidence that categories are represented as clusters of similar memories or as single, abstract prototypes. Other theories have focused on how learners formulate rules in the decision process. Collectively, these theories account for a wide variety of existing phenomena but many models are lacking in how they map onto brain structure and function. As well, some models and theories account for the same phenomena with differing assumptions. In order for the field to progress, research should strive to reconcile these differences and to identify how these models account for biological and well as cognitive phenomena. The proposed research advances our understanding of the science of categorization and creates new opportunities for exploration and discovery. I am proposing several studies to examine the fundamental cognitive mechanisms that operate when people learn categories. The data will be used to validate and refine existing computational models of categorization that were developed in my previous NSERC grants. These models will be used to generate predictions for advancing the computational cognitive neuroscience of categorization. I will build on recent work in my lab that measured electrophysiology in the brain by collecting EEG while participants learned novel concepts. I am also proposing an fMRI study to examine the role of a specific area of the human hippocampal system, the perirhinal cortex, that may play a role in the integration of new percepts with existing memory. This region may be less active in older adults and this reduced activity may be responsible for age-related deficits observed in our earlier work. My research is significant to the cognitive sciences in general because an understanding of categorization is crucial to the understanding of other abilities such as language, problem solving, and reasoning. The results of my research also help to inform the field on the optimal learning and performance environments in different scenarios. My research program has been enhanced by recent investments by the University and the Federal and Provincial governments targeting the study of cognitive neuroscience at Western University. This includes a new research building completed in 2017 that houses the Brain and Mind Institute. My research lab, doctoral students, master's students, and undergraduates, are housed in this new facility. These students will be involved in all stages of the proposed research program, will co-author peer-reviewed publications, and will present the research at national and international conferences.