The Role of Working Memory in Attentional Allocation and Grammatical Development under Textually-enhanced, Unenhanced and No Captioning Conditions

This study investigated the extent to which individual differences in working memory (WM) mediate the effects of captions with or without textual enhancement on attentional allocation and L2 grammatical development, and whether L2 development is influenced by WM memory in the absence of captions. We employed a pretest-posttest-delayed posttest design, with 72 Korean learners of English randomly assigned to three groups. The groups differed as to whether they were exposed to news clips without captions, with textually-enhanced captions, or with unenhanced captions during the treatment. We measured attentional allocation with eye-tracking methodology, and assessed development with an oral production, a written production and a fill-in-the-blank test. To assess various aspects of WM, we employed measures of phonological and visual short-term memory (PSTM, VSTM) and the executive functions of updating, task-switching, and inhibitory control. We found that, in both captions groups, higher PSTM was associated with higher oral production gains. For the enhanced captions group, PSTM was also positively related to gains on the written production test. Participants in the no-captions group, however, showed a positive link between VSTM and oral production gains. Attentional location only correlated positively with updating ability and PSTM under the enhanced captions condition. These results, overall, indicate that WM can moderate the effects of captions on attention and L2 development, and various WM components may play a differential role under various captioning conditions.