Chapter 1　Introduction

　1.1　Research background

　1.2　Research questions

　1.3　Significance of the study

　1.4　An overview of chapters

Chapter 2　Literature Review

　2.1　Individual difference variables in SLA

　2.2　Development of studies on individual differences

   ……

Chapter 1　Introduction

1.1　Research background

As the focus of studies on foreign language learning and teaching shifted from language teaching to language learners in the 1970s，the research on individual differences began to receive increasing attention.From then on，the studies of individual differences have undergone three stages（Cui & Liu，2013）.The first stage was initiated by the univariate studies which focused on the characteristics that made some learners more successful than others（e.g.Rubin，1975；Stern，1975；Naiman et al.，1978）.The good language learner studies can make us better understand the behavioral and mental features of successful learners.However，later on，critics pointed out that the studies on good learners alone cannot justify that the characteristics identified are exclusive for good learners and no sufficient attention was given to poor learners who might also share those features（Purpura，1999）.As a result，researchers started to compare successful learners with unsuccessful ones in terms of their learning strategies，beliefs，learning styles and foreign language anxiety（e.g.Huang & Van Naerssen，1987；Andersen，1991）.A multitude of comparative studies were conducted from 1980s to early 1990s，but the majority of them focused on a single variable and produced rather inconsistent and sometimes contradictory results.The discrepant findings might be attributed in part to different methodologies，definitions and classifications of the same factor or different samples.However，the most important reason lies in the assumed linear relationship between individual differences and learning outcome.Most studies have considered individual difference variables to be isolated from each other with little attention to the interactions among them（Ellis，1994）.In the late 1990s，scholars began to realize that it is the interaction of learning strategy，attitude，motivation and other variables that accounts for learners differential success（e.g.Gardner et al.，1997）and they started to include more variables in their studies（e.g.Wen & Johnson，1997）.As the focus of research shifted from a single factor to multiple factors，the studies of individual differences entered the second stage.

The second stage was characterized by multivariate studies which accounted for learners differential success from an interactive perspective.This stage lasted from the 1990s to the beginning of the 21st century although a small number of univariate studies were still performed during this period.Some scholars focused on the interaction of two variables（e.g.Wen，1995；Lee，1999；Albert，2006）and others incorporated more than two variables in their studies（e.g.Wen & Johnson，1997；Gardner et al.，1997；Ghavamnia et al.，2011；Sioson，2011）.The studies that can be considered the most comprehensive in this stage were conducted by Wen and Johnson（1997）who incorporated learning strategy，learner belief，effort and learning purpose in their research and Gardner et al.（1997）who studied seven variables simultaneously among the same sample group.Gardner et al.（1997）developed a second language acquisition model which describes the interaction of language aptitude，learning strategy，anxiety，motivation，learning style，attitude and selfconfidence.The research was carried out among American students learning French as their second language.Learners from different cultural backgrounds differ in their foreign language learning.As a result，we are not sure whether the model can be generalized to the Chinese EFL context.In addition，the study considers individual differences as a state at a particular point in time，ignoring their dynamic and developmental nature.The studies at this stage mostly focused on how two or more than two variables operate in concert to contribute to EFL achievement.However，they ignored the fact that different learner factors constitute an inseparable system and need to be integrated to account for differential success among EFL learners.Such integrated studies require a more comprehensive theoretical framework.Conveniently，there has already been such a theoretical paradigm available that can be used to describe individual differences as an integrated，dynamic and nonlinear system.It is Dynamic Systems Theory（DST）.With the introduction of DST into the studies of individual differences in the late twentieth century，the research in this area moved into the third stage.

The third stage was featured with comprehensive studies which examined individual differences from a dynamic system perspective.Dynamic Systems Theory，also referred to as complex dynamics or complex systems theory，originated from the theory of dynamics proposed by Newton in the seventeenth century and the nonlinearity principle in mathematics.DST emphasizes complete interconnectedness，sensitivity to the initial conditions，variability and nonlinearity of system behaviors.According to the theory，the components of a system are interdependent，inseparable and the behavior of a system is the result of interaction of all its components.As Drnyei（2010）pointed out，individual differences can be better accounted for in terms of a dynamic system as there are a number of parallels between DST and individual differences such as dynamism.The basic philosophies of DST such as interconnectedness and dynamism can provide the very theoretical basis we need to solve the current dilemma in the studies of individual differences.Against the DST backdrop，researchers were increasingly aware of the limitations in previous studies and started to turn their attention to the possible application of DST to the studies of individual differences.Drnyei（2009）first opted for a DST approach to understanding learner characteristics and conceptualized the relationships between language，agent and environment in second language acquisition process from a DST perspective.Drnyei has made groundbreaking effort to introduce DST into the studies of individual differences.Drnyei（2010）also established a tripartite framework of human mind which consists of cognition，affect and motivation and identified three higherorder combinations within this framework，namely aptitude/trait complexes，interests and possible selves.Most studies on individual differences from a DST perspective centered on a single variable，such as motivation（e.g.Drnyei，2003，2009）.Studies in this line marked a major step forward from univariate and multivariate studies as they fully justify the dynamic nature of individual differences.However，there have been few attempts to consider multiple variables as a macro dynamic system and examine how they interact with each other in a dynamic fashion.As a result，the present study intends to examine the interrelationships among eight learner factors and the relationship between these variables and EFL achievement from a dynamic system perspective.The learner factors selected as the focus of this study include learning strategy，learner belief，motivation，foreign language anxiety，learning style，language aptitude，effort and personality，which are chosen because they are most extensively researched and generally recognized as the typical individual difference characteristics.

1.2　Research questions

Individual difference variables which constitute a dynamic system should be viewed as an inseparable whole which exerts joint influence on EFL achievement.This can be manifested by the following three aspects.First，as components of the system，some learner factors are closely related to each other while others are distantly connected.Therefore，they are grouped into different subsystems，which further constitute the system of individual differences.Second，different subsystems interact with each other and with the entire system in a dynamic and complex manner.There are also complex interactions going on within each subsystem.Third，different components and subsystems function together to achieve certain level of EFL proficiency，which also affects the constituents of the system in turn.

Researchers hold different ideas as to which factors should be regarded as EFL learners individual differences（e.g.LarsenFreeman & Long，1991；Drnyei，2005；Ellis，2008a），with the list of individual differences being expanded continuously to include new factors such as willingness to communicate（WTC）or creativity.It is impossible and unrealistic to incorporate all individual difference variables in a single study.Therefore，eight key factors are selected as the focus of the present study，including learning strategy，learner belief，motivation，foreign language anxiety，learning style，effort，language aptitude and personality.This study aims at exploring the dynamic interaction of major learner factors and intends to build a model for the dynamic system of learners individual differences.The following three paired research questions are proposed accordingly：

1）How can a dynamic system of individual differences be built？What are the subsystems within the dynamic system and the components within each subsystem？

2）What are the interrelationships within each subsystem and between different subsystems？How do their interrelationships change over time？

3）How do individual differences jointly contribute to EFL achievement and how does EFL achievement affect individual differences in turn？How do their interrelationships change over time？