The Role of Proficiency on the Use of Cognitive Control During Second Language Processing

Restricted (Penn State Only)
Author:
Grant, Angela Marie
Graduate Program:
Psychology
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
February 27, 2017
Committee Members:
  • Ping Li, Dissertation Advisor
  • Ping Li, Committee Chair
  • Janet Van Hell, Committee Member
  • Nancy Dennis, Committee Member
  • Carrie Jackson, Outside Member
Keywords:
  • language learning
  • cognitive control
  • inhibitory control
  • language training
  • control training
Abstract:
This dissertation examines the use of cognitive control during second language (L2) processing by adult language learners. Although cognitive control has been acknowledged as an important component of language processing for many years, its conception in the language literature was largely as a top-down mechanism of inhibition. In two experiments I explore the role of a complementary type of cognitive control, bottom-up control, and how second language proficiency modulates its use. Experiment 1, a functional MRI study, investigated the blood-oxygen-level-dependent (BOLD) signal correlates of bottom-up and top-down non-linguistic control, as well as semantic processing in the L1 and L2 by Spanish learners varying in proficiency. I found that high proficiency learners showed less activation in the caudate nucleus (CN), a crucial component of the top-down control network, and increased activation in the cerebellum and superior temporal gyrus, two areas associated with bottom-up control. I additionally observed that the multivariate activity patterns in regions associated with top-down control (including the CN and prefrontal cortex) were more similar in high proficiency learners, and that the connectivity between these regions was more efficient than in low proficiency learners. Experiment 2 considered how training on top-down and bottom-up control could affect acquisition of new foreign language vocabulary, and found that top-down control training significantly speeded responses compared to bottom-up training and a sham condition. Together, these experiments suggest that low proficiency learners rely more on top-down control during L2 processing, while high proficiency learners may transition to a more bottom-up control process mediated by more posterior regions associated with cue detection and selective attention. These findings provide empirical support for the relevance of the conceptual distinction between top-down and bottom-up control to language learning. Furthermore, applying this distinction allows for the reconciliation of current theories of language learning, which differ in their predictions concerning the role of proficiency in how language learners use cognitive control.