Designing a task with a reasonable level of cognitive complexity has always been important for syllabus designers, teachers, as well as researchers. This is because task manipulation may lead to different results in oral production. The present study was an attempt to explore the effect of this manipulation - based on Robinsonâs resource-directing model (reasoning demands, number of elements, and here and now versus there and then condition) - on picture narration. The study included 30 Iranian EFL learners at the intermediate level between the ages of 21 and 34. They were all native speakers of Persian. Each participant was required to perform the simple version as well as the complex version of the same picture narration task. The participantsâ speech was audio-recorded and the results revealed that an increase in task cognitive complexity leads to greater accuracy and linguistic complexity.