Bishop and Cates (2001) provided a framework for thinking of instructional sound from a cognitive perspective (see Table 8.4). Although their primary goal was investigating the potential of sound in support of instructional software, the framework also is useful for considering the medium of sound in isolation. The three types of noise come from the work of Shannon and Weaver, which has been interpreted by Bishop and Cates (2001) from a cognitive instructional viewpoint. Acquisition noise interferes with the reception of an
instructional message. Processing noise refers to problems with understanding the message that has been received. Retrieval noise is a mismatch between an understood message and prior knowledge, experience, or attitudes.