2. Review of Literature
Listening has long been the neglected skill in second language acquisition, research, teaching, and assessment. However,
in recent years there has been an increased focus on L2 listening ability because of its perceived importance in language
learning and acquisition. Few empirical studies have explored the potential relationship between prior knowledge and
listening comprehension. Mueller (1980) investigated the effects of background knowledge on listening comprehension
of locus of contextual visuals for different levels of aptitude of beginning college German students. The aptitude
variable consisted of two levels (high and low) determined by the participants' grades in the preceding German course.
He found that the students who had the contextual visual before hearing the passage scored significantly higher on the
recall measure than those in the visual-after and the no-visual groups.