Psychology
Permanent URI for this communityhttp://hdl.handle.net/1903/2270
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Item Conflict and Competition between Model-based and Model-free Control(2020) Lei, Yuqing; Solway, Alec; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)There are two learning systems behind human decision-making: the model-based (MB) system and the model-free (MF) system. While they both contribute to decision-making behaviors, it is not clear how the two systems interact to formulate a single decision, especially when they are in conflict. This present thesis defines decision conflict between the systems in two popular binary-choice tasks: Daw’s Two-step task and Kool’s Rocket Task. We used hierarchical modeling to identify conflict-related changes during decision process using the Drift-Diffusion Model (DDM). Evidence showed that the MB system compromises when there is a conflict with the MF system, whether the conflict is on the valuational level or action level. We also looked at how a key component of obsessive compulsive disorder (OCD), the cognitive self-consciousness (CSC), affects the two learning systems during decision.Item The Valuation of Social Reinforcement in Schizophrenia(2015) Catalano, Lauren Theresa; Blanchard, Jack J; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Facial affect perception impairments impede social functioning in schizophrenia. What remains unknown is how individuals with schizophrenia assign value to pleasant facial expressions that typically motivate social affiliation. The current study adapted a matching pennies game (Shore & Heerey, 2011) to assess the subjective value of social feedback in terms of money. Individuals with schizophrenia and controls were instructed to choose the same side of a coin as six computerized partners, each of whom provided different rates of monetary feedback and types of social feedback. In a later test phase, participants chose which partner to play from amongst pairs of partners. Among participants who appropriately learned task contingencies, individuals with schizophrenia failed to use genuine smiles to motivate choices to the same extent as controls; however, money was equally valued. These findings suggest that there is a reduced sensitivity to social rewards in schizophrenia.