论文总字数：52713字

摘 要

1. Introduction 5

2. Literature Review 2

2.1 Theoretical issues 2

2.1.1 Levelt’s Model of Oral Production 2

2.1.2 Working memory 3

2.1.3 Planning 4

2.1.4 The interplay of working memory and planning on oral production 4

2.2 Empirical studies 5

2.2.1 Studies on the effects of working memory on oral complexity 5

2.2.2 Studies on the effects of planning on oral complexity 6

2.2.3 Studies on the effects of WM and planning on oral complexity 6

2.2.4 Limitations of previous studies 7

3. Methodology 9

3.1 Research questions 9

3.2 Participants 9

3.3 Data collection 10

3.3.1 Computerized reading span test 10

3.3.2 Picture-narrative task 10

3.4 Procedure 11

3.5 Data analysis 12

3.5.1 working memory 12

3.5.2 complexity 13

4. Results and Discussion 14

4.1 Results 14

4.2 Discussion 18

5. Conclusion 21

5.1 Major findings of the research 21

5.2 Implications 21

5.2.2 Pedagogical implications 22

5.3 Limitations and suggestions for future research 23

References 24

Appendix 30

Acknowledgments

With several months` hard work, this thesis is finally finished. It signify that my college life will end soon. During the short two years, I experienced a lot and benefited a lot from the surroundings. By the way I would like to take this opportunity to express my gratitude to all the people who have helped me.Linguistics is always a difficult and obscure subject for me, so the writing of this paper is one of the biggest challenges I have ever encountered in my life. My sincere and deep gratitude goes firstly to my supervisor, Mr. Han, for his arduous effort in helping me to choose the topic, design the framework, collect the samples and use the software to analyze the data from the very beginning to the end. Without his patient guidance, continuous encouragement and general support, this paper would not have been possible. To my surprise, I am gradually interested in linguistics under the influence of Mr. Han, instead of avoiding it and being afraid of it. Furthermore, I feel honored to benefit a lot from his personalities and diligence and am deeply impressed by his rigorous academic attitude.

Special thanks go to a postgraduate student, Liu Si who has given me so much valuable advice and help me learn the statistical analysis. I also appreciate her emotional support and encouragement in the process of my thesis. Besides, I need to thank the 56 sophomores of English majors who took part in my test and helped me finished my thesis.

I would like to thank all the other teachers for their enlightenment, knowledge, encouragement and help throughout my undergraduate study at Nanjing Technology University.

Finally I would like to give my sincere thanks to my dear families and friends for their love and support all these years.

Abstract

Oral production is a complex cognitive activity. This study examines how planning time and working memory capacity affect Chinese EFL learners’ oral production in the case of oral complexity. Most previous studies have explored the effects of working memory and planning on L2 oral production respectively; whereas little research has been conducted on both how the effects of working memory and planning time on oral production, especially on oral complexity. Thus, this study aims to explore the effects of the working memory capacity and planning on L2 oral complexity. Specifically, it addresses the following research questions:

1. Is there any effect of working memory capacity on Chinese EFL learners’ oral English complexity?

2. Is there any effect of planning time on Chinese EFL learners’ oral English complexity?

1. Does the effect of planning time on complexity of oral English complexity vary according to the difference of working memory capacity?

The present study was a 2 (working memory capacity)×2 (planning time) two-way ANOVA design. The 51 second-year English major subjects, whose language proficiency was at the same level, were from two intact classes in a university of technology in China. The subjects were divided into low working memory capacity group, and high working memory capacity group based on their performance in working memory test. It was measured in terms of information processing and information storage by a Chinese computerized reading span test (RST) adapted from the version made by Daneman and Carpenter (2009). The subjects were divided into two groups, i.e., the group provided with planning and the group without given planning time. L2 learners’ oral complexity was measured by clause per T-unit and Type/Token ratio.

A series of two-way ANOVA was conducted with the data in the study. The major findings are as follows:

1. Working memory capacity has a significant effect on L2 learners’ oral complexity in lexical complexity, but not in syntactic complexity. The results indicate that L2 learners with high working memory capacity perform better in lexical complexity than those with low working memory capacity.

2. Planning time has a significant effect on L2 learners’ oral complexity in lexical complexity, but not in syntactic complexity. The results also show that the two working memory capacity groups have improved with the aid of planning time on oral complexity.

3. There is no significant interaction effect between working memory capacity and planning time on L2 learners’ oral complexity both on syntactic complexity and lexical complexity.

Key words: working memory capacity, planning time, oral accuracy, oral production

中文摘要

口语产出是一项复杂的认知活动。本研究考察了工作记忆容量和准备水平对中国英语学习者口语复杂度的影响。工作记忆容量和准备水平分别对二语学习者口语产出的影响，前人研究较多，然而，仅有少数研究探讨了工作记忆容量和准备水平对口语产出的影响，特别是对口语复杂度的影响。因此，本研究旨在探究工作记忆容量及准备水平对二语学习者口语复杂度的影响。研究问题如下：

1. 工作记忆容量对中国英语学习者口语复杂度是否有显著影响？

2. 准备水平对中国英语学习者口语复杂度是否有显著影响？

3. 工作记忆容量和准备水平对中国英语学习者口语复杂度是否有交互影响？

本研究是一个2 × 2 二因素设计。在此次研究中，受试者为来自某工业大学两个班的51名英语水平相似的大二英语专业学生。工作记忆容量是一个组间变量，并通过中文版阅读广度测试将受试者分为两组，即高工作记忆容量组和低工作记忆容量组。中文版听力广度测试就两方面进行测量：信息加工能力和信息存储能力。为了避免英语水平差异给工作记忆容量测量带来的影响，本研究所采用的中文版阅读广度测试时在Daneman和Carpenter (1980) 的版本上改善的。本研究准备水平是组间变量，将其分为两组，有准备时间组和无准备时间组。二语学习者的口语复杂度通过平均每一个T-单位所包含的从句数和型符类符比进行测量。

本研究通过二因素方差分析，得出以下结论：

1. 工作记忆容量对而与学习者口语词汇复杂度有显著影响，但对句法复杂度没有显著影响。研究结果表明，高工作记忆容量被试的口语复杂度均高于低工作记忆容量被试者。

2. 准备水平对二语学习者口语词汇复杂度有显著影响，对句法复杂度没有显著影响。通过分析发现，有准备时间组，不论工作记忆容量的高低，表现均高于无准备时间组。

3. 工作记忆容量和准备水平对二语学习者的口语复杂度没有显著的交互效应。

关键词：工作记忆容量 准备水平 口语复杂性 口语产出

Introduction

In recent years, research on oral production has draw much attention on second language acquisition (SLA). However, few research have consistent conclusions on oral complexity. Working memory capacity and planning time are two important criteria to measure EFL learners` oral complexity. In light of the debates on the effect of working memory capacity and planning time on EFL learners’ oral English complexity, the present study is aimed at investigating the effects of working memory capacity and planning time on China’ s EFL learners’ oral English complexity.

Literature Review

2.1 Theoretical issues

2.1.1 Levelt’s Model of Oral Production

L2 oral speech production are encouraged based on Levelt’s (1989) model of L1 speech production. According to Levelt (1989), the speaker need to pass through a great deal of processes, That are conceptualization, formulation and articulation, audition and speech-comprehension system. Conceptualization is irresistible when individuals communicate with each other. Then intermediate representations of messages generated in the components of the system (Conceptualizer, Formulator and Articulator) are stored for further processing.

The distinctive aspect between controlled and automatic processing (Shiffrin amp; Schneider, 1977) is important in Levelt’s speech production model, because these two processes, usually quick, are carried out without purpose or conscious awareness and operate on their own resources, while controlled processes require attentional resources. Besides, controlled processes are usually successive, and therefore time-consuming. In Levelt’s model, message generation (in the Conceptualizer) involves highly controlled processing. The conceptualization and feedback system have been enormously draw speakers’ attentions. The other parts of Levelt’s model are claimed to be largely automatic in L1. In the light of L2 speech production, a series of processing tasks are involved in the process of speech production, namely, organizing communicative use of speech, activating the concepts, excerpting lexical meaning, through the excerpt of lexical meaning to encoding verbalization, grammatical and phonological information and monitoring and modify speech production. Connected with each other seamlessly, these tasks have a requirement for controlled processes to a great degree, and resulted in difficulties in L2 accuracy, fluency and complexity (Jin, 2012).

Levelt’s speech production model cannot account for the individual differences of processing ability although it can preferably describe the process of L2 speech production. According to Payne and Whitney (2002), the process of L2 speech production can be better understood only by combining Levelt’s speech production model with other concepts of cognitive psychology, particularly working memory theory.

2.1.2 Working memory

Originally, Baddeley and Hitch put forward that working memory is defined as section of the human memory system that combines both the temporary storage and process of information during the performance of a series of complex cognitive tasks such as understanding, learning and reasoning.(1974). There are three reversely independent sections of working memory: they are phonological loop, visuo-spatial sketchpad and central executive ( Baddeley, 2002, Baddeley, 2003; Baddeley amp; Hitch, 2002).

Working memory is usually defined as the limited capacity cognitive mechanism that enables us to temporarily store several pieces of information in mind and process information during the performance of complexity cognitive tasks while comprehending, thinking, speaking, and doing( McLaughlin; Heredia, 1996; Daneman; Carpenter, 1980, 1983; ).

Miyake (1998) defined the working memory as a working area, full of resources or activation which in favor of both conduct of different token computations and maintenance of intermediate outcome generated through the computations (p. 341.).

Working memory capacity is also called “short-term store” or short-term memory, primary memory, immediate memory and refers to the temporary processing and storage of information. The central executive system is the core of working memory, also a control system with limited capacity. There have been a large amount of models proposed concerning how working memory operates, both anatomically and cognitively. One of the most important of them is Baddeley and Hitch’s multi-component model.

If working memory (hereafter WM) acts a significant difference between high-and-low working memory capacity (hereafter WMC) individuals in terms of complexity cognitive activities, Rosen and Engle(1997) thought that only individuals who having great WMC were able to implement verbal tasks fluently while monitoring their output. Therefore, one may assume that individual differences in WMC would significantly correlate with the extent to which L2 learners benefit from the opportunity to prepare their speech in favor of producing reasonably more complexity, accurate, and fluent language.

2.1.3 Planning

Levelt thought of planning as the chance to plan how to complete the task and how to perform the task well before the practical performance. Briefly, it is the cognition process of considering or organizing what you will do in the event of something. This process involves both preverbal automation (Levelt, 1977; Baars, 1980) and long-term organization of utterance.

Yang believed that planning is a sort of psychological activity, which attending the process of completing certain tasks, which was thought of as the target-oriented.

Das, Kar and Parrila’s give the definition to planning, the role of planning works in need of completing a series of tasks.

2.1.4 The interplay of working memory and planning on oral production

Ellis indicated, although planning is a way of aiding learners get over insufficient in working memory capacity and advance their performance (2005).

Ortega believed that there are at least two reasons to account for that individual differences in working memory capacity may still exist in planned performance. Firstly, it seems that planning advance performance through provoking a series of strategic, metalinguistic and metacognitive behaviours (2005). Second, the benefits of planning on performance may also depend on the ability to execute what was planned into performance (1999).

Foster, Skehan and Mehnert, these researchers on the effects of planning on L2 speech performance discussed results in terms of a limited attentional model of learning. They declare that gains in accuracy,fluency and complexity may not be obtained concurrently since these respects of speech performance compete for our limited working memory capacity (Foster; Skehan, 1996; Mehnert, 1998, among others).

Guará Tavares (2009), who investigated the in interaction between pre-task planning and WMC, reveals that planning, generally, and working memory capacity interact in complex and intricate ways to affect L2 oral performance. Individuals with higher WM capacity have more attentional resources accessible to distribute towards these processes more effectively and, thus, obtain more fluent and accurate speech performance .

2.2 Empirical studies

2.2.1 Studies on the effects of working memory on oral complexity

Some researches have been conducted to probe into which working memory capacity is related to EFL learners’ oral complexity. (Fortkamp, 2000, Finardi, 2008;)

Jin’s study found that working memory capacity and there is a significant correlation between second language level, and the correlation coefficients above 0.6

(plt;.001). In order to more clearly and truly reflect the influence of working memory capacity on second language oral output, the researchers looked at the control level of second language variable affect working memory capacity after a partial correlation relationship with the second language spoken output.

Rosen and Engle(1997) found that only individuals who having great WMC were able to implement verbal tasks fluently while monitoring their output. They also pointed out that individuals who having low WMC would make more errors. Researchers and scholars in the field of SLA, who admit the role that differential WMC plays in which learners are successful to some degree in L2 acquisition and performance. Research findings facilitate support to this hypothesis.

2.2.2 Studies on the effects of planning on oral complexity

A number of studies have investigated the effects of planning on L2 learners’ performance of oral narratives(e.g., Ellis, 1987; Foster amp; Skehan, 1996; Ortega, 1999;Robinson, 1995; Skehan amp; Foster, 1997,1999; Wendel, 1997;Yuan amp; Ellis, 2003). Generally speaking , studies have shown a positive impact of panning on L2 performance, specifically, planning can increase complexity (Crookes,1989; Foster; Skehan,1996; Mehnert, 1998; Ortega, 1999;Yuan; Ellis,2003). These studies pointed out that learners would have the opportunity to prepare how to conduct a narrative before they speak it (i.e., pretask planning) resulted in remarkable enhancement in complexity (measured in terms of the degree of subordination).

Furthermore, Although Yuan and Ellis found that pretask planning resulted in increased complexity in oral production. (Ellis-R-Yuan), Yuan and Ellis’s results back up the controversy that performance in SLA is influenced by contending demands, resulted in that participants’ attention to one respect of language shifts from participants’ ability to care about another respect. Foster and Skehan(1996) assume that they trade off accuracy and complexity in the service of oral production.

2.2.3 Studies on the effects of WM and planning on oral complexity

In last decades years, a growing number of researchers have conducted the effect and development of working memory capacity and planning time on oral production from home and abroad.(Ellis, 1987; Foster amp; Skehan, 1996; Ortega, 1999;Robinson, 1995; Skehan amp; Foster, 1997,1999; Wendel, 1997;Yuan amp; Ellis, 2003;Jin, 2012 ). However, there are few researchers study both the interplay effects of working and planning time on oral complexity.

Maria da pointed out the results of his studies that planing leads to gains in fluency and complexity at the cost of gains in accuracy (Mehnert, 1998). Despite the fact that researchers explain results in terms of learners’ limited attentional resources, individual differences in working memory capacity have not been taken into account in any of these studies as a feasible variable affecting learners’ planned performance.

While Guara-Tavares (2009) has been the only study designed to explore the connection between low working memory capacity and pre-task planning, there have been many empirical investigations of the effects of pre-task planing time (Mehnert, 1998; Ortega, 1999 amp; 2005; Yuan amp; Ellis, 2003).

Ortega points out the following in her pre-task planning multiple studies (1999): ‘(a) planned output is both more fluent and more syntactically complex than unplanned output, and (b) results for grammatical accuracy are conflicting and inconclusive ’ (p. 118). The mixed effects for accuracy might be because planning time cannot compensate for difference in competence: If L2 learners do not have solid mental representation of linguistic structures, pre-task planning time will not put them into their heads. Some research has also suggested that if attentional capacity is limited, learners focus on complexity at the expense of grammatical accuracy (Skehan, 1998). Additional, Ortega (2005) found that for the low-intermediate students, pre-task planning time resulted in greater lexical complexity, but for advanced learners, there was no difference in lexical complexity for students who received time for pre-task planning.

Mendonca, McNamara, Scott, and Weissheimer, have conducted researches, which on memory has manifested that individuals with higher WM capacity tend to be more strategic (Weissheimer, 2007), thus, WM capacity may play a role on how successful one is in engaging in strategic behavior during planning.

2.2.4 Limitations of previous studies

In the past few years, oral complexity has successfully attracted much attentions and the growing number of scholars come into notice the necessities of studying the working memory capacity and planning time in the process of oral production and improving the ability of the speech communication. However, there still exist some limitations in the previous studies.

Firstly, from the previous studies, we could easily learn that the researches on oral complexity are relatively scanty and fewer research finding are yielded, compared with those on oral fluency and accuracy. In addition, there is fewer researches referring to the relationship between the working memory capacity and planning time. And much fewer researches related to oral syntactic complexity and lexical complexity between the working memory capacity and planning time.

Secondly, more studies focused on the oral production and the development, the theoretical analysis of oral complexity, lacking practical measures. In other words, both qualitative and quantitative analyses are necessary. Both oral syntactic complexity and lexical complexity studies should be balanced conducted under different conditions. And all the possible factors including emotion, types of tasks and preparation conditions with different planning time and so on rarely were taken into consideration.

To sum up, there are still many insufficiency in the previous studies, which call for the implement of the present study.

3. Methodology

3.1 Research questions

The present study aims to investigate the effects of working memory capacity,and planning time on China’s EFL learners’ oral complexity. Thus, the research questions are addressed as followings:

1. Is there any effect of working memory capacity on China’s EFL learners; oral English complexity?

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