الخلاصة:
This study seeks to examine the influence of task complexity on English as a foreign language students’ and teachers’ perceptions of task difficulty. Thus, thirty students, in the Department of English, Oum El Bouaghi University, Algeria performed four argumentative writing tasks, varied in complexity along ± strategic planning and ± causal reasoning, following a repeated measures design. Then, they gauged the difficulty of each task and indicated the features that influenced the appraisal via a questionnaire. Furthermore, thirty teachers, from the same department, answered the questionnaire to rate the tasks’ difficulty and discuss their reasons. The descriptive analysis demonstrated that both respondents rated the fourth task as the most difficult. The qualitative analysis showed that the prevalent themes were mostly related to the cognitive factors of tasks. These results have compelling pedagogical implications that contribute to the establishment of a basic task difficulty index in writing.