The Effect of Task Complexity on Fluency and Lexical Complexity of EFL Learners' Argumentative Writing

Karim Sadeghi, Zahra Mosalli


Based on Robinson’s (2003) Cognition Hypothesis and Skehan’s (1998) Limited Attentional Capacity Model, this study explored the effect of task complexity on the fluency and lexical complexity of 60 university EFL students’ argumentative writing. Task complexity was manipulated through applying resource-dispersing factors. All participants were randomly assigned to the one of the three groups: (1) topic, (2) topic + idea, (3) topic + idea + discourse marker group. One-way ANOVA was utilized to detect significant differences among the groups. Results showed that increasing task complexity (1) produced significantly less fluency, and (2) did not lead to differences in lexical complexity (measured by the ratio of lexical words to function words and lexical density), but it did lead to significant differences when mean segmental type-token ratio was used to measure lexical complexity.  Further findings and implications are discussed in the paper.



Fluency, Lexical complexity, Lexical density, Task complexity, EFL learners, argumentative writing

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Ahmadian, M. J., & Tavakoli, M. (2011). The effects of simultaneous use of careful online planning and task repetition on accuracy, complexity, and fluency in EFL learners’ oral production. Language Teaching Research, 15(1), 35-59.

Anderson, A., & Lynch, T. (1988). Listening. Oxford: Oxford University Press.

Arslanyilmaz, A., & Pedersen, S. (2010). Improving language production using subtitled similar task videos. Language Teaching Research, 14(4), 377-395.

Bereiter, C., & Scardamalia, M. (1987). The psychology of written composition. Hillsdale, NJ: Erlbaum.

Carter, R. (1987). Vocabulary: Applied linguistic perspectives. London: Routledge.

Chandler, J. (2003). The efficacy of various kinds of error feedback for improvement in the accuracy and fluency of L2 student writing. Journal of Second Language Writing, 12, 267–96.

Dörnyei, Z. (2007). Research methods in applied linguistics. New York: Oxford University Press.

Ellis, R. (2008). The study of second language acquisition. Oxford: Oxford University Press.

Ellis, R. (2009). The differential effects of three types of task planning on the fluency, complexity and accuracy in L2 oral production. Applied Linguistics, 30, 474–509.

Ellis, R., & Yuan, F. (2004). The effects of planning on fluency, complexity, and accuracy in second language narrative writing. Studies in Second Language Acquisition, 26, 59–84.

Fontanini, I., Weissheimer, J., Bergsleithner, J. M., Perucci, M., & D’Ely, R. (2005). Memória de trabalho e desempenho em tarefas de L2. Revista Brasileira de Lingüística Aplicada, 5 (2), 189-230.

Haberlandt, K. F., & Graesser, A. C. (1985). Component processes in text comprehension and some of their interactions. Journal of Experimental Psychology: General, 114, 357–374.

Ishikawa, T. (2006). The effect of manipulating task complexity along the (- Here - and - Now) dimension on L2 written narrative discourse. In C. M. Garcı´a-Mayo (Ed.), Investigating tasks in formal language learning (pp. 136–156). Clevedon, UK: Multilingual Matters.

Jacobs, H., Zinkgraf, S., Wormuth, D., Hartfiel, V. & Hughey, J. (1981). Testing ESL compositions: A Practical approach. Rowley, MA: Newbury House.

Kellogg, R. T. (1988). Attentional overload and writing performance: Effects of rough draft and outline strategies. Journal of Experimental Psychology: Learning, Memory, and Cognition, 14, 355–365.

Kellogg, R. T. (1990). Effectiveness of prewriting strategies as a function of task demands. American Journal of Psychology, 103, 327–342.

Kellogg, R. T. (1996). A model of working memory in writing. In C. M. Levy & S. Ransdell (Eds.), The science of writing: Theories, methods, individual differences and applications (pp. 57–72). Mahwah, NJ: Erlbaum.

Khomeijanifarahani, A. A., & Meraji, S. R. (2011). Cognitive task complexity and L2 narrative writing performance. Journal of Language Teaching and Research, 2(2), 445-456.

Kim, Y. (2009). The effects of task complexity on learner-learner interaction. System 37, 254-268.

Kormos, J. (2011). Task complexity and linguistic and discourse features of narrative writing performance. Journal of Second Language Writing, 20, 148-161.

Kuiken, F., & Vedder, I. (2006). Cognitive task complexity and linguistic performance in French L2 writing. In M. Garcı´a-Mayo (Ed.), Investigating tasks in formal language learning (pp. 117–135). Clevedon, UK: Multilingual Matters.

Kuiken, F., & Vedder, I. (2008). Cognitive task complexity and written output in Italian and French as a foreign language. Journal of Second Language Writing, 17, 48-60.

Kuiken, F., Maria, M., & Vedder, I. (2005). Cognitive task complexity and second language writing performance. In S. H. Foster-Cohen, M. Garcı´a- Mayo, & J. Cenoz (Eds.), Eurosla yearbook (pp.195–222). Amsterdam: Benjamins.

Long, M. (1985). A role for instruction in second language acquisition: task-based language teaching. In K. Hyltenstam, & M. Pienemann (Eds.). Modelling and assessing second language acquisition (pp.77-99). Clevedon: Multilingual Matters.

McCarthy, P. M., & Jarvis, S. A. (2007). Vocd: A theoretical and empirical evaluation. Language Testing, 24, 459–488.

Nassaji, H., & Tian, J. (2010). Collaborative and individual output tasks and their effects on learning English phrasal verbs. Language Teaching Research, 14(4), 397-419.

Ojima, M. (2006). Concept mapping as pre-task planning: A case study of three Japanese ESL writers. System, 34, 566–585.

Ong, J., & Zhang, L., J. (2010). Effects of task complexity on fluency and lexical complexity in EFL students’ argumentative writing. Journal of Second Language Writing, 19, 218-233.

Robinson, P. (2005). Cognitive complexity and task sequencing: A review of studies in a Componential Framework for second language task design. International Review of Applied Linguistics, 43, 1–33.

Robinson, P. (2007). Task complexity, theory of mind, and intentional reasoning: Effects on L2 speech production, interaction, uptake and perceptions of task difficulty. International Review of Applied Linguistics, 45, 193–213.

Robinson, P., Chi-chien Ting, S., & Urwin, J. (1995). Investigating second language task complexity. RELC 26, 62-78.

Samuda, V., & Bygate, M. (2008). Tasks in second language learning. Basingstoke: Palgrave.

Skehan, P. (1998). A cognitive approach to language learning. Oxford: Oxford University Press.

Skehan, P. (2001). Tasks and language performance assessment. In M. Bygate, P. Skehan, & M. Swain (Eds.), Researching pedagogic tasks: Second language learning, teaching and testing (pp. 167–185). Harlow: Pearson Education Longman.

Skehan, P. (2003). Task-based instruction. Language Teaching, 36, 1–14.

Skehan, P., & Foster, P. (2001). Cognition and tasks. In P. Robinson (Ed.), Cognition and second language instruction (pp. 183–205). New York: Cambridge University Press.

Suzuki, M. (2006). Negotiation processes and text changes in Japanese learners’ self revisions and peer revisions of their written compositions in English. Unpublished doctoral dissertation, University of Toronto, Canada.

Weir, C., O’Sullivan, B., & Horai, T. (2006). Exploring difficulty in speaking task: An intra-task perspective. IELTS Research Reports 6.

Wigglesworth, G., & Storch, N. (2009). Pair versus individual writing: Effects on fluency, complexity and accuracy. Language Testing, 26(3), 445-466.

Wolfe-Quintero, K., Inagaki, S., & Kim, H.Y. (1998). Second language development in writing: Measures of fluency accuracy and complexity. Honolulu, HI: University of Hawaii Press.



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