The Effect of Isolated vs. Combined Processing Instruction and Output-Based Instruction on the Learning of English Passives

The studies on the merits of processing instruction (PI) and output-based instruction (OI) have mostly treated the two approaches as mutually exclusive. To address the potentials of combining interpretation and production activities, this research compared the two isolated approaches of PI and OI with two combined approaches in which processing and output tasks were used in two opposite orders suggested by the researcher, i.e.  processing-output-based instruction (POI) and output-processing-based instruction (OPI). The target structure was English passives. Participants included 185 Iranian EFL students from five intact classes, with four assigned to each treatment and one comprising a control group. Results on sentence-level interpretation and production tests administered before, immediately after, and one month following instruction indicated similar improvement for the treatment groups on the first interpretation posttest, and the superiority of POI over OPI and PI over the delayed posttest. On the first production test, POI, OPI, and OI performed equally well and better than PI, while more accurate uses of the target form were observed by POI and OPI on the delayed posttest. It was concluded that the combined approaches, particularly POI, could produce more persistent outcomes by giving learners the opportunity to both process a form and produce it.