While the above can account for a great deal, we are left, nevertheless, with some interesting questions. For one thing, when and why did so many of the Bantu groups abandon P/B style for the type of vocal interaction now most common among them today, what is usually referred to as "call and response"? I don't think the change in musical style could have coincided with the separation from the "founding" group, because there are still certain Bantu tribes that do in fact still vocalize in P/B style -- some with yodelling as well (see map). It seems likely, therefore, that there must have been a split among the Bantu at some point after their separation from the founding group.
Why am I talking in terms of a "split," which implies a rather sudden occurrence, rather than a more gradual "evolutionary" process? Here, it seems to me, we come across a problem of fundamental importance to an understanding of history, both musical and otherwise. Let's assume that, after the initial separation from the "founder" group, the Bantus remained intact as a single unit over a very long time, and that during this time all sorts of gradual changes could have occurred, including musical ones, leading step by step to the replacement of P/B by call-and-response. Then, after the latter style had been established, the original Bantu population began to break up into the smaller units we are familiar with today, the groups that eventually spread throughout Africa during the "Bantu expansion."
This might seem reasonable until we ask ourselves 1. why the Pygmy and Bushmen groups did not also gradually evolve away from P/B style? 2. why Bantu vocal music ceased to evolve after the call-and-response style had been established, prior to the Bantu expansion? Everything we know about the music of traditional peoples tells us that they have a very strong tendency to maintain their traditions intact, from one generation to the next; and since the generations overlap, in some cases at intervals as short as 15 years or less, there is little opportunity for any sort of fundamental change to become established.
It seems to me, therefore, that there must have been a split at some point, something rather sudden, that divided the Bantu into two groups, those that maintained the original P/B style and those that for some reason were not able to maintain it. This is in line with an approach to evolution generally that's come into prominence in recent years, known as "punctuated equilibrium," very close in theory to the notion being promoted nowadays among the geneticists, the "population bottleneck." What's implied is that some small part of an originating population becomes isolated from the main group, possibly as a result of a dispute, or warfare, or some natural catastrophe, etc.
For example, let's say that a small group of very young children from one tribe are captured by a rival tribe and then abandoned in a remote area of a forest, and left to die -- but some survive. As they have never been fully assimilated into the prevailing traditions, the survivors will not be in a position to maintain such traditions in their original complexity, but will be forced to simplify. And if their descendents manage to survive and multiply, then the simplified versions of the old traditions will suddenly become established as new traditions, which will in turn be passed on intact from generation to generation. This is, of course, only one of many possible scenarios, but the general idea is the same -- what could be called, by analogy with the "population bottleneck" of the geneticists, a "cultural bottleneck," leading to so-called "founder effects" that produce new cultural variants, including new musical styles (or sub-styles). Thus, the call-and-response polyphony now so common among so many Bantu groups, could have had its origin in some relatively sudden event now lost to history, that produced a new type of population with a somewhat different cultural outlook from its predecessor. The new outlook could also have led to new types of complexity along different lines, such as the proliferation of the many different instrumental traditions now found among so many Bantu groups, but not Pygmies and Bushmen.
Since I'm operating on three different tracks here, I'll move on now to the second. Where we left off was with the table I provided, listing all the groups in New Guinea and Island Melanesia Cantometrically coded as exhibiting vocal interlock (see the previous post). I'll add one more group to the list, from the Bosavi region of New Guinea, as recorded by Steven Feld. While most of our sample from this region was not coded as interlocked, there is in fact a performance possibly not in the original sample that does exhibit both interlock and yodel, a recording of a men's work group.
Before examining the table in detail we need to consider some background issues. There are two large language families in greater Melanesia: Austronesian and so-called "Papuan." The former is generally regarded as much more recent than the latter, associated with groups that originated somewhere in SE Asia and spread during the last 4,000 years or so, first to Melanesia and then to Polynesia. Most of these newer populations settled along the coast of New Guinea, and also in various parts of Island Melanesia. "Papuan" is the name given to the languages of the people thought to be more properly "indigenous" to the area, who were presumably already living there when the Austronesians arrived. The "Papuan" languages are actually a group of apparently unrelated language families, along with several languages regarded as unaffiliated "isolates."
One might assume that one could differentiate between the indigenous peoples and the more recently arrived groups on the basis of language, but the picture is in fact much more complicated than that, because in many cases Austronesian languages have been adopted by the original groups, who no longer speak any version of "Papuan." A better measure of "indigenousness" is provided, at least in New Guinea, by location. According to most ethnologists and linguists, strongly reinforced by the most recent genetic findings, the highland regions of New Guinea are populated by indigenous groups, generally thought to have lived there for anywhere from 40,000 to over 60,000 years ago. The picture for Island Melanesia is unfortunately far more complex, linguistically, geographically and genetically.
With the above in mind, what is truly remarkable about the table I've presented is the fact that out of 11 (12 if we include the Bosavi example) groups in New Guinea coded as interlocked, all are from the highlands, with only a single exception, the Kovai, who live on an island off the northern coast. Additionally, all these groups, including the Kovai, speak Papuan languages. I'll have more to say about the meaning of this correlation in my next post.
More now on our puzzler, this time courtesy of Phillip Tagg (http://www.tagg.org/xpdfs/origins3.pdf):
According to the Lu Shih Chun Qiu or Lu Buwei the foundation tone of music is huang zhong, which literally means ‘yellow bell’. ‘This was conceived simultaneously as a sacred eternal principle, the basis of the state and a note of definite pitch in music. Lu Buwei attributes it to the mythical Emperor Huangdi (third millennium BP) who sent the equally mythical Ling Lun (‘Music Ruler’) to the western boundaries of the kingdom where, in a mountain valley, he cut a node of bamboo in such a way as to give the foundation tone — the pitch of a man’s voice when he spoke without passion. It was considered important to find the correct pitch for each dynasty, or political disorder would be likely to ensue’... ‘From the foundation tone, other higher notes were derived by taking a tube of length one third less than the first, then a tube one third more than the second and so on, that is, tubes alternately two-thirds and four-thirds the length of each preceding one. The resulting sounds thus have alternately vibrations of 3/2 and 3/4 times the frequency of the preceding, which gives’… ‘alternating series of ascending fifths and descending fourths. It will be seen from this that the vibration frequencies in the Chinese system are all based on powers of the numerals 2 and 3’. The Yueji ( ‘Memorial of Music’) and Liji ( ‘Record of Rites’, both c.450 BP) put these figures in cosmic perspective. ‘Music expresses the accord of Heaven and Earth’. ‘Since 3 is the numeral of Heaven and 2 that of the Earth, sounds in the ratio 3:2 harmonise as Heaven and Earth.’
If we posit the note f as the huang-zhong foundation tone of Chinese music theory, the first five notes in the series of pipes just described will be f-c-g-d-a. (fig.9a, p.16). Scalar rearrangement of these pitches produces f-g-a-c-d (fig.9b), the Chinese five-note scale identical to the European major- or doh-pentatonic scale. This system already existed in melodies from the time of the Zhou dynasty (1050- 255 BP) and Chinese texts from the fourth and third centuries BP call the five notes gong, shang, jiao, ji and yu. Any of these five might serve as centre for a new mode of the scale and each mode would be characterised by this note as its principal and final . . . In other words, the procedure described thus far rationalised the origin of the ‘five notes’, establishing a physical theory of the major pentatonic mode and of modes deriving from any of its constitutent pitches.