LAUSR

Abstract This study investigates how working memory (WM) abilities are implicated in second language (L2) learners’ (a) morphosyntactic achievement and (b) perceptions of required mental effort and task difficulty under oral versus written task modality conditions. Beginning-level learners of L2 Spanish completed two computerized focused tasks in which they produced output and received feedback in oral form (Speaking group) or written form (Writing group). Two grammatical structures varying in their relative level of salience were targeted. After each task, participants rated their perceptions of mental effort required and task difficulty. Production and written and aural acceptability judgment tasks were employed to measure immediate and sustained L2 morphosyntactic achievement. Executive, phonological, and visuospatial WM abilities were gauged using automated operation span, nonword recognition, and forward Corsi block-tapping tasks, respectively. Regression analyses revealed that WM capacity was predictive of L2 morphosyntactic outcomes and task perception ratings in the Speaking group only. Specifically, phonological and visuospatial WM were associated with production and acceptability judgment performance accuracy, whereas executive WM was related to learners’ ratings of perceived mental effort. Differences were also observed based on the target structure.