The effects of task complexity on lexical complexity in L2 writing: An exploratory study

This study investigated the effects of task complexity on the lexical complexity of second language (L2) learners’ written production. Fifty-eight L2 English learners completed simple and complex versions of an argumentative writing task manipulated along two resource-directing variables: reasoning demand and number of elements. The essays were analyzed using a set of metrics that examined four different lexical complexity dimensions: lexical sophistication, psycholinguistic property, lexical diversity, and lexical density. For each dimension, we examined how metrics for all words (AW), content words (CW), and function words (FW) interact with each other. Results showed significantly higher levels of all four lexical complexity dimensions in the complex task than in the simple task. The correlations between the AW and CW metrics were consistently high for all lexical complexity dimensions in both task versions, while those between the AW and FW metrics and between the CW and FW metrics were relatively weak and varied by task. Our findings contribute to a better understanding of the interface between task complexity and L2 lexical use in the area of writing. These findings have useful theoretical and methodological implications for future task-based L2 writing lexical complexity research.