Effects Of Task Complexity On Second Language Learners’ Writing Performance: A Complex Adaptive System Theory Perspective

In recent years many scholars have paid attention to task,which is viewed as a factor to affect learners’ language proficiency.Writing is an important part of second language proficiency,of which language complexity is a significant index to measure learners’ writing performance.Besides,according to complex adaptive system theory(CAST),language is a dynamic system that is adaptive to environment.Meanwhile,Robinson’s hypothesis holds that task complexity affects the distribution of second learners’ attention,which further affects learners’ language production.Therefore,task complexity as a micro environment could affect English Learners’ internal language system,which interprets learners’ writing performance externally.Based on Robinson’s framework(2001)of task complexity,the present study conducts a one-semester study to try to capture L1 Chinese L2 English language learners’ writing performance as well as the linguistic development of their writing performance over four months.English major students are required to finish writing tasks with different scales of complexity in class.And then collection and quantitative analysis of the written texts are carried out,to contribute to the following questions: 1)Does task complexity affect English learners’ writing performance? If so,in what aspects does it affect writing performance? 2)Does English learners’ writing performance vary when dealing with the same complexity scale of writing texts after one semester? If so,what are the changes? 3)Do time and task complexity have interactive effects on the lexical and syntactic complexity in English learners’ writing performance?With the assistance of SPSS16.0 and online complexity analyzer,this study uses descriptive analysis and ANOVA analysis.Therefore,the results show that 1)Complex writing tasks contribute to improving lexical diversity and sophistication,as well as mean length of sentence,while decreasing coordinate and verbal phrase ratio.2)Within the same task complexity,lexical sophistication and diversity,and verbal phrase ratio increase after one semester,while mean length of sentence and coordinate phrase ratio decrease.3)Time and task complexity interact with each other in producing effects on English learners’ writing performance,including lexical sophistication and diversity,mean length of sentence and T-unit,as well as verbal phrase ratio.Among them,lexical sophistication and diversity,and verbal phrase ratio show a positive trend,while mean length of sentence and T-unit plays a negative trend.According to the results,there are implications for instructors: teachers can manipulate task complexity to make students allocate more attention to language forms.When dealing with complex task,they will produce more advanced,diverse words and complex sentence patterns.Therefore,teachers should gradually improve students’ abilities to use diverse words,complex phrases and clauses to replace simple sentences.In addition,instructors should inform students of the multidimensionality of second language writing and the necessity of mastering different dimensions.Certainly,there are inevitable limitations,and further studies need to be carried out to make a better contribution to the relevant research of task complexity and second language writing.