The definitions of knowledge as well as knowledge acquisition have been greatly influenced by the changing views of the human mind offered by psychologists and philosophers in the twentieth century. In the 1960s members in music profession sought to identify what was to be taught and what was to be included in the contents of music education. These concerns reflected the influences of the behavioral psychologists, including Thorndike, Hull, Osgood and Skinner. The examples of this pursuit were shown through Yale Seminar, Juilliard Repertory Project, and early concerns of Contemporary Music Project. The curricular implementation of San Diego Project, one of pilot projects conducted under the auspices of Contemporary Music Project, is illustrated in this research. In the 1970s music educators endeavored to clarify how students exhibit their understanding of music through the concept of Comprehensive Musicianship (CM). This view was influenced by the cognitive psychologists. In CM this how was to translate into such basic musical activities as performing, analyzing and creating. One example of CM classes for elementary school students is demonstrated here. Gardner`s theory of multiple intelligences and schemata theory advocated by some of cognitive psychologists have had great influence on the concerns and practices of music education since the 1980s. Especially Gardner`s theory provided such an impetus to re-think about the traditional assessment practices as producing an alternative mode of assessment which is based on mastery-standards and process-oriented. An example of the alternative assessment experienced by Gardner through Arts Propel project is presented in this study. Also the schemata theory has influenced music educators to focus on high level thinking such as creativity, critical thinking, problem-solving and meta cognition. A lesson plan designed to enhance these kinds of high level thinking for elementary school students is demonstrated here. All of these cognitive psychologists since the 1980s has agreed that music is specific area of knowledge, valuing it as the unique contribution to human learning and life. With the advent of cognitive psychology, more and more psychologists and music education scholars are compiling a body of scientific literature that support this claim.