The effects of task complexity on linguistic complexity and perception in English native speakers’ and L2 speakers’ argumentative writing

This study investigates how task complexity affects native speakers’ and second language (L2) learners’, and experts’ perceptions of task difficulty in writing tasks. It also explores how task complexity influences English native speakers’ and L2 learners’ linguistic complexity in their writing. Ninety participants performed one simple and one complex argumentative writing task manipulated by task complexity (± elements and reasoning demands) and counterbalanced. Their essays were analyzed using linguistic complexity metrics. The results showed that English native speakers, L2 learners, and experts perceived the complex task as requiring more mental effort, being more stressful, and creating more planning and writing time pressure than the simple task. The native speakers demonstrated greater overall linguistic complexity than the L2 learners in the two writing tasks. However, both English native speakers and L2 learners produced longer T-units and more diverse vocabulary in the complex task than in the simple task but also produced more syntactically similar structures in the complex task. Significant interaction effects of group (L1 and L2) and task (± elements and reasoning demands) were found for five linguistic complexity metrics. Theoretical and methodological implications are discussed in light of Robinson’s cognition hypothesis and Hayes’s writing model.