Abstract
The present study investigated how background knowledge and vocabulary knowledge held by Japanese readers affect reading comprehension of a science text written in English. In Experiment 1, three tests were administered to 175 Japanese high school and college students : a cloze test (to measure language skill), a vocabulary knowledge test, and a background knowledge test. The participants read a text written about the heart and blood circulation to answer text-based questions and inference questions measuring 'text-base' and 'situation model', theoretical concepts proposed by van Dijk and Kintsch (1983). Path analysis indicated that vocabulary knowledge causally affected 'text-base', which further showed inter-causal relations with 'situation model'. Background knowledge independently and causally influenced 'situation model' (see details in Figure 2). In Experiment 2,134 high school participants were divided into high-(n=37) and low-groups (n=45) of vocabulary knowledge. It was showed that participants with high vocabulary knowledge performed better in free recall and text-based questions than those with low vocabulary knowledge, whereas no significant differences were found in inference questions and text summarization. In Experiment 3,134 high school participants were divided into high-(n=34) and low-groups (n=36) of background knowledge. It was showed that participants with high background knowledge performed better in text-based and inference questions, and text summarization than those with low background knowledge while no significantdifference was found in free recall. The results of Experiment 2 suggest that although vocabulary knowledge leads to an increase in the numbers of micro propositions, this does not affect the construction of macro proposition. The results of Experiment 3, in contrast, suggest that although background knowledge does not affect the numbers of micro propositions, it contributes to the construction of macro proposition. As a result, background knowledge contributes to enhance the quality of both 'text base' and 'situation model'.
