Task Complexity and L2 Writing Performance: Syntactic Complexity, Grammatical Accuracy, and Learner Perceptions

Abstract

This study investigates the effects of task complexity on the L2 writing performance of Saudi students in UK universities, drawing on Robinson’s Cognition Hypothesis. It adopts a within-subjects repeated-measures design to examine whether task complexity influences syntactic complexity, grammatical accuracy, and learners’ perceptions. 20 Saudi EFL learners, with a proficiency level between B2–C1, completed two email-writing tasks: a low-complexity task and a high-complexity task. After each task, participants completed a post-task questionnaire on perceived difficulty, mental effort, and other affective states. Written texts were analyzed using the L2 Syntactic Complexity Analyzer (Lu, 2010). Results showed that syntactic complexity remained stable across tasks. Grammatical accuracy declined in the complex task, as reflected in significantly more errors per 100 words. Learner perceptions showed little change, though the complex task was rated slightly more difficult. The findings indicate that while learners maintained syntactic structures under greater demands, grammatical control was weaker. The study highlights implications for sequencing L2 writing tasks to balance challenge and engagement.