Culturally and historically the banjo is a mediator among African and European American cultures. Significantly, this mediation is fraught with a history of racism, classism, sexism, and erasure. The outline of that story may be followed in the history of minstrelsy, the attempted class and gender elevation of the banjo in the late nineteenth century, its subordination to the guitar and other instruments in jug bands, ragtime, and jazz in the twentieth century, its resurgence in the old-time and bluegrass musical revivals beginning in the mid-twentieth century, and its African American reclamation in the contemporary string band music of groups such as the Carolina Chocolate Drops and the Ebony Hillbillies, the Black banjo gathering, and the vigorous, current exploration of its African roots and historical connections in the Americas. The banjo is also a mediator experientially. In its role in the old-time string band, the banjo is a melodic and rhythmic mediator, as the banjo player attempts to interact with the fiddler and guitarist in a musical way that is constructive, integrative and creative, not merely expressive.
As a musical instrument,the best banjo mediates elements of the African musical bow, a one-stringed instrument formed like the bow that shoots an arrow, and other African stringed instruments which use a shell resonator such as a gourd or part of an animal, covered by an animal skin. The earliest African banjo-like instruments attached these resonators to sticks, not necks and fingerboards as on New World banjos. Strings were tied with loops, not tuning pegs, although pegs and fingerboards are found in banjos in the Caribbean in the 1600s. A fifth string (the one that sounds the lowest pitch and what modern players call the fourth string) was added in the nineteenth century and, later, frets as on the guitar were added to the fingerboard. The modern banjo is constructed out of wood and metal with its round pot over which is stretched the plastic or skin head that gives a percussive sound to the music that it plays. In effect it is a drum with a neck and strings. Four-string banjos (without the drone string) gained in popularity early in the twentieth century, when many variants were produced, chiefly by attaching different necks and fingerboards to the pot with a skin head: the banjo uke, the banjo mandolin, and the six string banjo-guitar being the most prominent. Evidently the pot was the sine qua non, the identifying characteristic of these banjo hybrids.
In the Sachs-Hornbostel classification of musical instruments, the banjo is usually regarded as a plucked lute, or chordophone. But a good argument may be made on the grounds of its drum head that it is also a membranophone. Although part of its sound comes from the chordophonal vibration of its strings, another part of its sound and timbre arises from the resonance it receives from its vibrating membrane, or head. In evading easy classification the banjo collapses the foundation of the most generally accepted system of musical instrument taxonomy. An organologist’s nightmare or delight, depending on how one looks at it, the banjo is the most changeable of instruments, the consummate hybrid, both fact and symbol of structural mediation, or ambiguity if one is inclined to interpret it that way.
Second, the banjo is a mediator in American cultural history. Scholars of American music have long proclaimed that the ragtime and jazz of the turn of the twentieth century was the first American music, in the sense that it was the first to escape European dominance and thus to reflect American cultural hybridity, and a gift to the world that revolutionized popular music in the twentieth century. But by this criterion, the first American music came a century or so earlier: the fiddle and fiddle/banjo dance music that resulted from Black-white musical interchanges in the nineteenth century, an exchange in which Native Americans also were involved. One of the popular forms arising from this exchange, minstrelsy, became a craze in America and Europe prior to the Civil War. Ragtime and jazz arose decades later as manifestations of that interchange.
Excerpted from http://folkloreforum.net/2012/06/28/music-mediation-sustainability-a-case-study-on-the-banjo/