Chapter One Introduction

Background of the Study

Grounding on the different theories of language learning and performance,tasks have been studied from a variety of perspectives in the research of SecondLanguage Acquisition (SLA). Over the last two decades, researchers have developedmainly four theoretical perspectives in the research of second language (L2) tasks.The first one is the structure-oriented approach, in which tasks are designed to elicitlanguage production of particular structure features (Loschky & Vroman, 1993;VanPatten, 1990). The second is the sociocultural approach, which treats tasks as aresource for participation in the dialogic processes in particular settings for shapinglanguage use and learning (Lantolf, 2000; Swain，1998; Swain & Lapkin, 2001). Thepsychological interactional approach is the third one, in which the interactive natureof language production is considered to be essential to second language acquisition.To be concrete, this approach emphasizes the importance of the negotiation ofmeaning during production.

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Objective of the Present Study

The present study adopts a cognitive approach to examine task effects viacognitive complexity on Chinese college students' L2 writing performance withregard to fluency，accuracy and complexity by applying three tasks of different levelcognitive load. It is hoped that the findings of this research can lend a support toeither Skehan & Foster's Limited Attentional Capacity Model or Robinson's TriadicComponential Framework. Therefore, the research question is put forward asfollows:What effects on accuracy, complexity，fluency do tasks with increasingcomplexity produce in Chinese EFL learners' writing? In recent years，studying the influence of cognitive load of 12 tasks on oraland written language production has become a burgeoning area of research in thefield of SLA. Tasks are manipulated by researches to examine learners' performanceand to test different theoretical constructs. This study，intended to examine theinfluences of task complexity on Chinese non-English major undergraduates' writtenproduction, has both theoretical and pedagogical significance.Theoretically, the present research has potential contribution to the testifyingof either Skehan's model or Robinson's model. The result can add more informationto understand the effect of task complexity on learners' language learning process inthe writing modality.

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Chapter TwoTheoretical Background

Task-based Approach to Language Teaching and Learning

Being an important methodological innovation in second language research,task-based language teaching (TBLT) has greatly influenced syllabus design,teaching methodology and materials development According to Rahimpour (2008，2010)，TBLT takes task as its unit of analysis and focuses on the capacity to performa task without explicit instruction of language forms. He proposes that TBLTfacilitates the understanding of a second language learning processing and createsmore favorable conditions for the development of L2, Just as Ellis (2009) proposes, TBLT can enable learners to acquire a new language system by getting learners toperform a series of tasks using their own linguistic resources. So the main concern oftask-based research has been the effects of task design and implementation variableson language production in terms of fluency, accuracy and complexity (Ellis & Yuan，2004). Being the core of TBLT，task has been defined by many researchers (Long,1985; Nunan, 1989; Prahbu，1987; Mllis，1996). Some of their definitions arenon-technical or non-linguistic. Skehan (1998)，based on the definitions of otherresearchers，puts put forwards that a task is an activity that has five keycharacteristics; meaning is primary; there is certain communicative problem to besolved; there is some sort of recognizable relationship to real-world activities; taskcompletion has some priority; the assessment of the task is in terms of outcome.Following Skehan's proposal, Ellis (2003) gives a clear definition to a pedagogicaltask.

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The Limited Information Processing Theory

The researches in SLA have drawn extensively attention on the limitedinformation-processing theory, whose basic postulate is that human beings possess alimited information processing capacity due to the limited capacity of short-termmemory (Kahnemen, 1973). The short-term memory, or the working memory isdescribed as the mechanisms and processes that control，regulate, and activelymaintain task-related information. Identifying stimuli consumes certain portion ofattentional resources, and the extent to which the attentional resources arc neededrelies on the complexity of the stimuli. If the processing of one stimulus consumesall the attentional resources, other stimuli will not be processed since workingmemory is limited in its capacity. However the stimulus itself cannot automaticallytake up attentional resources since the working memory system has a maincomponent: a central executive，which is flexible and under human's control. To bespecific, its function is to control the attentional resources, selecting and operatingthe appropriate cognitive processes，and inhibiting some others to avoid exceedingthe limited capacities of the processing system.

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Chapter Three Literature Review .......  23

Review of Relevant Researches  .......  23

Effects of Task Complexity on Learners' Oral Production .......24

Effects of Task Complexity on Learners' Writing Production ....... 30

Strengths and Limitations of the Previous Studies ....... 34

Strengths of the Previous Studies  .......34

Limitations of the Previous Studies ....... 34

Originality of the Present Study ....... 35

Summary    .......36

Chapter Four Research Design  .......  37

Research Questions and Hypotheses ....... 37

Research Procedures  .......39

Experimental Design ....... 41

Groups  .......41

Variables Involved in the Study ....... 43

Experimental Sequence .......44

Verification of the Hypotheses ....... 45

Summary  .......46

Chapter SixResult and Discussion

Results and Discussion of Hypothesis One

Hypothesis one predicts that accuracy will be significantly lower in the morecomplex task than in the less complex one. That is: the accuracy of G3 will besignificantly lower than that of G2; the accuracy of G2 will be significantly lowerthan that of Gl; and the accuracy of G3 will be significantly lower than that of G1.Results of Hypothesis One.Table 6.1 is the descriptive data and result of the accuracy of the languageproduced in the three writing tasks. The mean EFC of G1 is the highest (M=.6878),G3 is only second to G1 (M=.6426), and G2 has the lowest mean score (M=.5928).One-way ANOVA is carried out to test whether the differences are significant. F valuerefers to the ratio of between group variance to within group variance.

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Conclusion

The purpose of the present research is to testify two contradictory modelsconcerning task complexity: Skehan and Foster's Limited Attentional CapacityModel and Robinson's Triadic Componential Framework. Both of the two modelshave identified a series of task factors that are related to different levels of taskcomplexity or difficulty，which can influence the performance of task completion bylanguage learners. Both of them stress the significance of the allocation of attentionin task completion. However，they are different in their predictions of how anincrease in task complexity exerts impacts on language output in terms of fluency,accuracy and complexity. Skehan & Foster predict that the trade-off effect willbecome apparent accuracy and complexity since L2 learners' attentional resource islimited. However, Robinson predicts a quite different outcome that accuracy andfluency will not compete but increase simultaneously.

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