ROCK ART AND ACOUSTICS: INTENTIONAL, ACCIDENTAL, OR IRRELEVANT - PART 2?

Lithophones, Organ and Chimes,

Caverns of Luray, VA,

1906 postcard.

Last week I reported on Iegor Reznikoff's researches into the subject of acoustics of rock art sites. This week I am adding conclusions of a couple of other authors and other evidence.

In the acoustics of a cliff, cave, or rock shelter, there are essentially two types of sound that are considered: naturally occurring sounds such as water, wind, and animal noises, etc., and human-caused sounds (whether vocal or mechanical). Vocal human sounds would include speaking, singing, whistling, or imitating animal calls, etc. Mechanical human caused sounds include drums, flutes, whistles, bull-roarers, etc. - and lithophones. Lithophones are a human-caused sound as well but are often considered separately as a special type of musical instrument. A lithophone is a percussion instrument consisting of certain dense rocks that ring with musical notes when struck. Stalactites and stalagmite formations in many caves will do this as well as separate stones and boulders.

Concerning human-caused sounds Fazenda (et.al.) writes that "It is likely that both speech and music were part of the cultures that used the caves, given that speech evolved earlier and examples of musical instruments in the human cultures under study here have been reported in archaeological studies." (p. 1337)

While it is undeniable that some echoes or resonance effects will be produced in virtually any cave or rock shelter, or even open cliff rock art site it has to be remembered that although geologic time seems unchanging there are continuous changes and modifications to the shapes and surfaces of these sites.

"At the same time it must be recognized that the internal morphology and structure of the caves has undergone processes of modification (both human and natural) that inevitably affect their acoustics. Some areas of these caves may hence exhibit acoustic responses that have changed since prehistory. The most significant naturally occurring change to the architecture of the caves came about through the closing or sealing of their original entrances by rock-falls or by sediment accumulation." (Fazenda et al. 2017:1334-5)

This means that the acoustic effects being detected today may be different than any effects intended when the rock art was created, and basing scientific assumptions on conditions that may have changed seems to make little sense. Also, rock art sites can have wildly different acoustic properties; from amplified resonance, to diminished or muddled resonance.

Painted Canyon, Val Verde County, TX,

photograph Peter Faris, March 2004.

I have even been at a rock art site that acted as a whisper channel wherein a sound made at one point cannot be heard just a few feet away, but is legible again farther down the rock face. This was a cliff face with a slight overhang in a narrow canyon in Texas. The cliff face was pretty much evenly covered with small, delicate red-painted figures, just as many occurring in the null area where the sound was not heard as in the areas of sound receptivity. If acoustic properties governed the placement of rock art I would expect the null area to have many fewer red-painted figures than the areas of intensity. This site, at least, seems to go against the rock art/echoes assumptions.

In their rigorous and excellent 2017 study of acoustics in rock art sites Fazenda and his ten co-authors concluded: "Blesser and Salter (2009:74) observe that, "cave wall images are tangible, enduring manifestations of early humans," and that in contrast sound "has no enduring manifestation, nor of course could it have for any pre-technical peoples," meaning that as a result, "available data are too sparse to draw strong conclusions." In our work a statistical association has been established between acoustic response and the positions of Palaeolithic visual motifs found in these caves. Our primary conclusion is that there is statistical, although weak, evidence, for an association between acoustic responses measured within these caves and the placement of motifs. We found a statistical association between the position of motifs, particularly dots and lines, and places with low frequency resonances and moderate reverberation. Importantly, we must reiterate that the statistically significant association does not necessarily indicate a causal relationship between motif placement and acoustic response. In other words, our evidence does not suggest that the positioning of motifs can be explained simply through relationships with acoustics, and we are not suggesting that motif positioning was based solely on an appreciation of sound properties. Indeed, we also found that motifs are statistically less likely to be found further into the caves, away from its original entrance, and this result further illustrates the complex relationship between early human behavior and features of these caves." (Fazenda:1347)

Great Gallery, Horseshoe Canyon,

Canyonlands, Wayne County, UT,

photograph Don I. Campbell,

May 1984.

As an example of the above, probably the most remarkable correspondence of echo and rock art I have personally experienced is the Great Gallery in Horseshoe Canyon, Canyonlands, Utah. The cliff wall there seems ideal for rock art and it has inspired a considerable amount of great art there on it. It also casts what I remember as  a strong echo, but even while standing there in front of it and experiencing it I got no sense that the art and the echo had to be somehow connected by other than coincidence.

I know that I do not have the last word on a subject, and I feel that I always have to leave room for error in my assumptions, so I will say here that it is possible that all the claims made for sites that produce strong echoes were chosen for rock art as well because of those echoes. But I know of no way of proving that and, until we do, many of the current claims are unsupported and overblown. The same rock face that is desirable for rock art purposes, probably also is desirable for echoes or other acoustic effects, but that does not mean that the art and the sounds are interrelated in any way.

NOTE: Some images in this posting were retrieved from the internet with a search for public domain photographs. If any of these images are not intended to be public domain, I apologize, and will happily provide the picture credits if the owner will contact me with them. For further information on these reports you should read the original reports at the sites listed below.

REFERENCES:

Blesser, B., and Salter L.
2009 Spaces Speak, Are You Listening?:Experiencing Aural Architecture, MIT Press, Cambridge, MA.

Fazenda, Bruno, et al.
2017 Cave Acoustics in Prehistory: Exploring the Association of Paleolithic Visual Motifs and Acoustic Response, The Journal of the Acoustical Society of America, 142, (1332-49), https://doi.org/10.1121/1.4998721