Edited by Zhisheng (Edward) Wen and Mohammad Javad Ahmadian
[Task-Based Language Teaching 13] 2019
► pp. 95–132
Chapter 5. Unravelling cognitive task complexity
Learning from learners’ perspectives on task characteristics and second language performance
Cognitive task complexity, which refers to the complexity or difficulty of a given task, has received substantial interest from researchers in various fields, including task-based language teaching (TBLT), second language acquisition, language testing, cognitive psychology, and education. In TBLT, researchers hope to make sense of complexity in order to design tasks that promote L2 performance, interaction, and learning. In this domain of research, Peter Skehan’s contributions are seminal. His Limited Attentional Capacity approach (1998) has inspired a large number of studies on cognitive task complexity and encouraged a healthy theoretical debate. In particular, his careful observations of the relationship between task characteristics and learner performance (as seen, for example, in Skehan, 2009, 2016) have demonstrated the importance of exploring in detail the nature of particular task characteristics (a priori design features and beyond) and the associated possibilities for improvement or deterioration in learners’ task performances.
Inspired by his work, the current study explores how learners responded to four picture-based oral narration tasks with varying degrees of complexity by design. A total of 120 English-L2 speakers in Japan narrated four picture sequences, each containing one, two, four, or nine characters (hence, varying degrees of cognitive task complexity by design). To gauge their perceptions of each task, learners rated each version according to perceived difficulty and mental effort exerted, and they provided written explanatory comments for their ratings.
Participants’ comments revealed three overarching categories of factors to which they attributed difficulty/effort associated with the tasks: conceptual input, code complexity, and performance factors. Further analysis of their comments from the perspective of Cognitive Load Theory (Sweller, 1994) indicated that difficulty/effort was associated with three distinct types of cognitive complexity: (a) intrinsic complexity related to learners’ English proficiency; (b) extraneous complexity that was perceived to be deleterious or irrelevant to task performance; and (c) germane complexity that encouraged learners to focus on improved performance. Of particular interest for task designers, the task with a combination of low extraneous and high germane complexity elicited the best performances, as measured by syntactic complexity, linguistic accuracy, lexical variety, and fluency indices. The paper concludes by indicating directions to be taken in future task complexity research.