Task complexity, modality, and working memory in L2 task performance

Despite the prolific research on the effects of task complexity on performance, the applicability of the research findings on other task modes is limited due to its focus on oral language. Modality has recently started to gain interest for its potential for L2 development, and learner variables such as working memory is expected to mediate between task effects and performance. This study investigates the roles of task complexity and modality in task performance. It further examines how working memory is associated with task performance and mediates the effects of task variables on performance. Thirty-nine participants performed four argumentative tasks, which differed in task complexity and modality. Working memory was measured via reading span and operation span tests, and task performance was evaluated in terms of complexity, accuracy, and fluency. The results revealed that task complexity produced increased syntactic complexity but only by the phrasal-level measure. Task complexity led to decreased accuracy, but fluency was not affected by task complexity. Task complexity effects were similar across modalities. As for modality on performance, speaking was more accurate, but less fluent than writing. Interestingly, speaking produced higher syntactic complexity than writing. No significant relationship existed between working memory and any performance measures.