This study sought to investigate the effects of textual enhancement, explicit instruction, and topic familiarity on Korean college students’ leaning of the passive form and reading comprehension. It also explored whether there exist interactions between textual enhancement, explicit instruction, and topic familiarity in terms of the learning of the target form and reading comprehension. To this end, six classes of 157 Korean EFL college students were assigned to six groups, according to the three manipulated treatments of textual input enhancement, explicit instruction, and topic familiarity.
Two weeks prior to the treatment session, each group was asked to take a pretest. The pretest consisted of two types of tests: multiple choice questions for the measurement of the learners’ prior knowledge of the target form and reading comprehension questions for the their general reading ability. They also filled out a topic familiarity questionnaire aimed to examine the learners’ prior knowledge of the topic for the topic familiarity training. During the first treatment session, three out of the six groups received topic familiarity training using reading tasks. Immediately after the training, they answered the same topic familiarity questionnaire again. During the second treatment session, the first two groups read a textually enhanced passage with explicit instruction, another two groups read a textually enhanced passage without explicit instruction, and the last two groups read an unenhanced passage. Five minutes after reading the passage, a written recall task was conducted in order to see what the participants could recall from the reading. During this second session, the same treatment and recall task was implemented with a different text. Following all treatments, the experimental groups also completed a form recognition posttest, used to determine processing of the forms. All of the statistical analyses were carried out using SPSS with a level of significance set at 0.05.
The major findings of this study are as follows. First of all, the results of the form learning test indicated that the groups given enhanced texts without explicit instruction did not benefit from visually enhanced target forms, whereas the groups that were given enhanced texts with explicit instruction showed a significant improvement in grammar scores. In addition, no significant difference was found among the groups with enhanced texts and those with unenhanced text. Therefore, it can be said that textual enhancement alone does not aid the students in attending to the target grammar, but textual enhancement with explicit instruction has a positive effect on students'' target grammar learning. However, the present study revealed that topic familiarity training had no significant effect on learners’ processing of grammatical forms. Thus, it seems that topic familiarity does not promote learners’ ability to make form-meaning connections, at least with the passive form.
Second, the results of the free recall task showed that regardless of explicit instruction, the students with the enhanced texts outperformed those with the unenhanced texts on reading comprehension. This result indicated that textual enhancement did not hinder, but rather helped, the learners’ understanding of the passage. The results also revealed that the groups given the topic familiarity training scored better than those not provided with it. Thus, it can be inferred that students’ reading comprehension is affected by the role of either textual enhancement or topic familiarity.
Last, this study also showed that there was no interaction effect between input enhancement, explicit instruction and topic familiarity regarding the learning of the target grammar. However, in terms of reading comprehension, significant interactions exist among the three treatments, especially between input enhancement and unfamiliar topics. In other words, while offering both input enhancement and explicit instruction only affected the learning of a target grammar, topic familiarity or interaction between unfamiliar topics and input enhancement did have an effect on reading comprehension.
The findings of this study have important implications for English education.
First, it is suggested that textual input enhancement itself may not be an effective tool for learning of a target grammar rule. Therefore, it should be augmented with additional treatments to enhance the learning of a grammar feature. In addition, textual enhancement may affect the learners’ understanding of a reading passage. Second, this study shows that topic familiarity would not lead to learners’ learning of a target form, but it does boost learners’ understanding of a passage. Last, it is also indicated that, when implementing classroom instruction, three treatments should be properly adjusted according to the purpose and content of the class.