Abstract
Despite the extensive studies being done regarding the effects of background knowledge on reading comprehension, there is little research that investigates the relationships among background knowledge, L2 reading proficiency, and reading comprehension. The present study examines Japanese EFL learners' reading comprehension from this perspective, specifically if L2 reading proficiency has a stronger effect on reading comprehension than background knowledge does. The results indicate that when questions for a reading comprehension test are more difficult, L2 reading proficiency appears to be a stronger factor than background knowledge in reading comprehension. Weakening or reducing the background knowledge effect by adjusting the difficulty of reading comprehension tests is one implication of the findings, which may modify the conventional way of selecting text material for EFL reading tests.
