Effects of Task Complexity and Individual Differences on EFL Writing Performance

Abstract

Grounded in the English-as-a-foreign-language (EFL) learning context, this research investigates the effects of writing task complexity, the predictive power of cognitive and psychological individual differences, and the moderating effect of task complexity on argumentative writing performance through the lens of multidimensional metrics. To differentiate writing tasks demanding different levels of cognitive resources, number of elements in two writing tasks was manipulated. To investigate learner individual differences, this research examines foreign language aptitude, Willingness to Communicate (WTC), and Foreign Language Enjoyment (FLE) for their claimed significance to foreign language learning. Writing performance was measured by syntactic complexity, lexical complexity, phraseological complexity, accuracy, and writing quality. This research adopted a mixed-methods design to combine the merits of both quantitative and qualitative approaches. In total, one pilot study and three main studies were conducted to achieve the research aims. First, 522 post-pubertal EFL learners from China were invited to participate in Study One in three steps to develop and validate an L2 writing WTC scale. Then, the pilot study recruited 20 participants to pilot the procedures, instruments, interviews, coding, and analysing. Finally, 166 intermediate post-pubertal EFL learners from China were recruited voluntarily to participate in Studies Two and Three, in which they were guided to join two cross-sectional quasi-experiments. The results indicate that (1) the newly developed and validated L2 writing WTC scale has a five-factor underlying structure; (2) an increase in number of elements leads to lower accuracy, higher lexical complexity, and higher phraseological sophistication in writing; (3) increasing number of elements leads to longer length of syntactic units, more complex noun-phrase modification, and more complex post-modification; (4) foreign language aptitude cannot predict writing quality; (5) L2 writing WTC, FLE, and multiple indices of complexity and accuracy can predict writing quality; (6) task complexity does not moderate the relationships between the three individual difference variables and writing quality. The conclusions aid previous research in determining the effects of task complexity and learner individual differences on EFL argumentative writing performance. Implications, limitations, and recommendations are discussed for EFL writing pedagogy and assessment.