Psychology
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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 What and Where of Control in Bilingual Language Switching(2018) Shell, Alison; Slevc, L. Robert; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Speakers of multiple languages must somehow express intended concepts using the appropriate lexical item in the intended language while not producing lexical items from another language that could equally well express the intended concepts. Thus bilingual speakers must presumably manage competition from these items active in their multiple languages in order to successfully communicate. However, it remains unclear where in the process of language production the competition exists, and what mechanisms are used to resolve the competition and successfully produce language. This dissertation set out to more robustly examine the implications of the prominent idea that domain general inhibitory control is used to inhibit the non-target language. To begin, I re-analyzed existing results from studies correlating measures of language switching and inhibitory control using a Bayesian approach. This reanalysis found that much of the previous literature either provides evidence against a relationship between a domain general inhibitory control task and language switching, or finds little to no evidence for such a relationship. Across two experiments, I then assess the role of domain-general inhibitory control in bilingual lexical access using a dual-task design–combining a language switching task with a concurrent task taxing domain-general cognitive control–as well as an individual differences component in the relatively well-powered and pre-registered Experiment 2. In these experiments, I break down the complex process of inhibitory language control into possibly dissociable levels of control (control at the language level and control at the item level) and assess potentially dissociable types of control (proactive control used to bias and monitor for conflict more broadly, and reactive control used for dynamically selecting between languages at a trial by trial level). There was evidence against a role of reactive control in switching between languages at both the language and item level. There was some evidence, however, suggesting a potential role for proactive control or monitoring in a language switching context. Correlations between language switching costs and domain-general measures of inhibitory control suggest that language proficiency and flexibility of control may modulate the ability to reactively control language in a language switching context, however the specificity of these findings demonstrate the complexity of this relationship, in line with the mixed findings in the current literature.Item THE ROLE OF DOMAIN GENERAL COGNITIVE MECHANISMS IN BILINGUAL LANGUAGE PRODUCTION(2015) Shell, Alison Ruppel; Slevc, L. Robert; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Bilingual language production is widely believed to be a competitive process. Bilinguals may manage this competition by relying on inhibiting one language while speaking in the other. However, it remains unclear if this process relies on domain general inhibitory mechanisms, and, if so, when and where during language production control is applied. The current study investigates these issues by experimentally manipulating demand on inhibitory control using tasks requiring domain-general inhibitory control, during a language switch task paradigm. If inhibitory control is required in language switching and is a domain general, inhibitory demand during the switch trials is predicted to make the switch more difficult. Across the experiments, switching costs were not exacerbated when inhibitory control was taxed; if anything, language switching was less costly during inhibition-demanding trials. These findings question the role of inhibitory control in language switching and suggest revising the current models of language control in bilingual production.