Understanding the role of the episodic buffer of working memory in inferential reading comprehension in L1 and L2 readers under varying conditions of cognitive load and domain knowledge

Abstract

In recent years, Baddeley (2010) has added a new component, the episodic buffer, to his Working Memory (WM) model. The episodic buffer binds information from long-term memory (LTM) to the central executive but has been researched very little, especially with respect to its use with a second language. In fact, Juffs and Harrington (2011) stated, “To date there has been no research on the possible role of the episodic buffer in L2 learning and use” (p. 140). One goal of this study was to do just that. Domain knowledge (DK) in baseball (Experiment 1) and English proficiency levels (Experiment 2) were used as proxies for difficulty level to study how inference processing under different conditions of domain knowledge and cognitive load in native (L1) and non-native (L2) English readers contribute to understanding the episodic buffer. In Experiment 1, 67 participants varying in domain knowledge about baseball read stories related to baseball with or without a concurrent cognitive load task of responding to tones while reading; they then answered comprehension questions of varying degrees of inferential difficulty. In Experiment 2, three groups varying in English reading proficiency, split into groups based on their lexical decision task scores (72 native, 40 intermediate, 40 beginner readers) read general stories with or without cognitive load and answered comprehension questions requiring varying degrees of inferential difficulty. Accuracy and Reaction Time (RT) were differentially affected by working memory (OSpan), cognitive load, and inferential complexity. In Experiment 1, greater DK explained variance in effectiveness (accuracy) and efficiency (RT) as inferential complexity increased. In Experiment 2 OSpan was needed even at lower levels of inferential complexity for beginning readers. Surprisingly, for both experiments, participants responded faster under cognitive load conditions, although not at the expense of accuracy. This suggests that the episodic buffer is important for different levels of DK and proficiency, especially as the task becomes more difficult. Theoretical and practical implications of these findings are discussed.