The Effects of Externally vs. Internally Driven Input Enhancement on the Intake and Acquisition Causative Structures

The present study was an attempt to examine the effect of externally driven vs. internally driven input enhancement on intake of the English causative structures on the part of intermediate EFL Iranian students. The two procedures of input enhancement were operationalized via input flooding and underlining, respectively. There were a total of 70 students participating in the study with an age range of 18 to 32. The learners were both male and female. They were assigned to three conditions- two experimental and one control. A pre-test, treatment, post-test type of design was employed. In order to expose the groups to the targeted structures a set of reading texts were used. The control group was exposed to neutral or base line texts in that there was no focus on the focused forms. For one of the experimental groups a set of texts enriched with the forms at issue was utilized (internally enhanced group). The second treatment group labeled as the underlining group was given a set of texts in that the targeted forms had been enhanced by underlining them. One-way ANOVA and paired wise post-hoc sample t-tests were performed on the results obtained from the tests administered. Results demonstrated that both technique were effective in promoting of the targeted forms and the both had durable impact on retention of the target items although not at the same rate. That is in both cases the underlining technique proved to be both more effective and had more lasting effect on noticing and intake of the causative forms. Our findings provided implications for both theory and pedagogy.