The Effects Of Task Complexity And Working Memory On Chinese EFL Learners’ Oral Task Performance

In the domain of task-based language teaching (TBLT), researchers have long been interested in exploring how internal task features affect language performance. Recently, from the cognitive perspective in TBLT, a lot of empirical studies have been conducted to test the effects of cognitive task complexity on task performance guided by two competing influential frameworks in TBLT, namely, the Limited Attentional Capacity Model (Skehan,1996b,1998) and the Multiple Attentional Resource model (or the Cognition Hypothesis) (Robinson, 2001a,2007a,2011b,2015). The two frameworks differ from each other in how learners allocate their attentional resources when they are engaged in performing tasks. Following the predictions of the two frameworks, a lot of research has been conducted to determine whether universal task design features exist which systematically influence learners’ interlanguage in predictable ways. However, most research carried out to date has focused solely on the impact of task complexity by manipulating cognitive demands along one of the dimensions in Cognition Hypothesis rather than exploring the synergistic effects of increasing task complexity along more than one dimension on language production. In addition, although researchers have posited that individual difference in working memory may play an important and differential role for SLA as working memory capacity is held responsible for individual difference in regulating attention, it has been a largely underrepresented construct in both conceptual and empirical work in task complexity study.The current study sought to fill this gap by designing a quantitative experimental study to investigate how Chinese EFL learners with different working memory capacities perform oral narrative tasks differing in cognitive complexity. The purpose of the quantitative study is two-fold.The prime objective of the study is to explore the relationship between task complexity along one or two of the cognitive dimensions of+/-reasoning demand and +/-contextual support and Chinese EFL learners’oral narrative performance; the second major aspect of this study is concerned with how Chinese EFL learners’ oral narrative performances with tasks differing in cognitive complexity are mediated by their differences in working memory capacities.A repeated measures design is used to obtain oral production data from 48 Chinese EFL learners elicited by performing four conditions of Task Complexity along+/-contextual support and+/-reasoning demand dimensions. Each participant narrates each of four pictures operationalized in different task complexity, the sequence of learners’ task performances are controlled by means of a Latin square design. Learners’ oral productions are measured in terms of complexity, accuracy and fluency. Repeated ANOVAs and pairwise comparison are employed to find out within-group difference for participants in performing tasks differing in cognitive complexity. Independent sample t-test is run to explore differences in task performance between higher working memory capacity group and lower working memory capacity group. The major findings of the present study are as follows:Findings revealed a complicated relationship among cognitive demands, working memory capacity, and learner task performance. Overall, the results suggest that Chinese EFL learners’ narrative oral performances were affected by manipulating along the two dimensions of task complexity, but the patterns of task complexity on learner’s oral performance were different for the two working memory groups. For learners with lower working memory capacity, when performing tasks increasing in either or both dimensions of cognitive complexity their language performance was opposite to what were predicted in Robinson’s hypothesis, but favored Skehen’s hypothesis. For learners with higher working memory capacity, when performing tasks increasing cognitive complexity on either of the two dimensions of cognitive complexity, the results confirmed what were predicted in Robinson’s Cognition Hypothesis; when performing tasks increasing cognitive complexity on both of the two dimensions of cognitive complexity, the results were opposite to what were predicted in Robinson’s hypothesis, but favored Skehen’s hypothesis. In addition, the research results showed moderating effects of working memory capacity when learners with different working memory were engaged in performing the same tasks.Based on the results of the present study, the dissertation concludes that task complexity,learner’s differences in working memory capacities and their task performance are interrelated with each other. Despite some limitations, the present study may offer a new perspective to our understanding of the two competing theoretical frameworks in TBLT. It also provides some pedagogical implications on how tasks should be designed to meet learner’s individual needs in Chinese EFL context.