The effect of input-based and output-based tasks with different and identical involvement loads on Iranian EFL learners’ incidental vocabulary learning

The purpose of this study was to investigate the effect of the input-based and output-based tasks with different and identical degrees of involvement loads on Iranian EFL learners’ incidental vocabulary learning. The participants were 120 pre-intermediate EFL learners from five English language institutes in Iran. In Phase 1, the participants received input-based and output-based tasks with identical involvement loads. In phase 2, they received both types of tasks but the involvement load of input-based tasks was higher than that of the output-based ones. Finally, in phase 3, the participants received output-based tasks with higher involvement loads. To measure the amount of vocabulary learning, immediate post-tests and delayed post-tests were administered upon completion of the tasks and a week after the post-tests, respectively. The results revealed that input- and output-based tasks with identical involvement loads had a positive significant effect on students’ vocabulary learning and retention at both the post-test and the delayed post-test. Also, input-based tasks with higher involvement loads had no significant effect on students’ vocabulary learning and retention at the post-test and delayed post-test. Finally, output-based tasks with higher involvement loads had a positive significant effect on students’ vocabulary learning in both the post-test and delayed post-test. The findings have pedagogical implications for teachers and materials developers in developing effective tasks with a sufficient amount of involvement load