The differential effect of explicit and implicit instruction on secondary school learners' collocational knowledge

The aim of this thesis is to investigate the effect of two types of instruction on the adjective + noun collocational knowledge of secondary school learners. The study employs a quasi-experimental pre-test, post-test, and delayed post-test research design. Initially, The Second Version of Quick Placement Test developed by Oxford University Press and University of Cambridge Local Examinations Syndicate (Syndicate, 2004) was used in order to determine the level of English of the students. Two groups were formed as experimental and comparison. The experimental group comprised 7 girls and 14 boys, totalling 21 participants. In the same way, the comparison group was composed of 10 girls and 11 boys, totalling 21 participants. Later, two groups of secondary school learners, a comparison and a experimental group were provided instruction of adjective + noun collocations. In this collocational relation, the adjectives in the specified units in the students' course book were taken as basis and their collocation with head nouns were targeted at. The first group (comparison) was given implicit instruction while the latter (experimental) was administered explicit instruction regarding the use of the said construction. More specifically, the attention of the learners in the first group was attracted to adjective + noun collocations, whereas the attention of the learners in the second group was directed to the same collocational patterns, which the study aimed to raise the learners' awareness of. The study was based on a 10-week program comprising six weeks instructional period with four hours a week + comprising one week pre-test, one week post-test, and a delayed post-test two weeks later. Prior to the instruction, the learner group were administered a pre-test. Immediately after the instructional intervention terminated, both groups were given a post-test to measure the learning gains of the lexical collocations under focus. Two weeks later, the same groups were administered a delayed post-test to measure to what extent they had retained the new knowledge that they had been exposed to. In this research study, the non-parametric alternative Friedman Test was applied in order to find out if there was a significant difference within groups and Mann-Whitney U test was utilised to find out whether there was a difference between groups regarding the intervention. Based on the results of the non-parametric alternative Friedman Test, no statistically significant difference was found in the comparison group while student gains were statistically significantly different between pre to post-test and pre- to delayed post-test in the experimental group. It can be said that the students in the experimental group benefited from the explicit collocational instruction. This is also confirmed by the finding obtained from the comparison between the post and the delayed post-test. The fact that there was no statistically significant difference between post and delayed post test indicates that students mostly retained the newly gained knowledge. However, according to the comparison of the obtained findings from Mann- Whitney U Test, it was found that there was no statistically significant difference in collocational knowledge score between the comparison and the experimental group. The study was concluded with implications as to the enhancement of the secondary school learners' vocabulary knowledge, and suggestions to improve the vocabulary instruction at secondary schools, and further research for the generalizability of the findings presented in the study. Key words: Explicit instruction, Implicit instruction, Collocations, Vocabulary retention