Leigh Dayton
Rock art evokes beastly echoes of the past
New Scientist, 28 November 1992, p. 14

Prehistoric artists chose sites with unusual acoustics for their paintings, claims an American scientist. This enhanced the impact of their work by giving the art a sound dimension.

Steven Waller of the American Rock Art Research Association recorded echoes at dozens of rock art sites in Europe, North America and Australia. He found that the subject matter of rock art is consistently related to the sounds that reverberate in the caves in which they are found.

Waller suspects that early artists used the caves' acoustics as a way to summon up the sound made by moving animals, and cites the percussive sounds created while making stone tools as an example of the type of sounds they could produce. He claims that when these are made in rock shelters, they evoke the sound of individual hooved animals running. On the other hand, similar sounds made in deep caves resemble those made by herds of animals such as bison, horses or bulls. "It's like the walls are alive," says Waller.

He told a recent conference in Cairns, Australia, that except where felines are depicted, echoes are key elements of every rock art site he has tested. Effective echoes can be made by yelling, clapping or making percussion noises.

At open air sites with paintings, Waller found that echoes reverberate on average at a level 8 decibels above the level of the background. At sites without art the average was 3 decibels. In deep caves such as Lascaux and Font-de-Gaume in France, echoes in painted chambers produce sound levels of between 23 and 31 decibels. Deep cave walls painted with cats produce sounds from about 1 to 7 decibels. In contrast, surfaces without paint are "totally flat'.

Waller has analysed data from 20 rock art sites in Western Europe. His preliminary measurements from North America and Australia indicate that the results will be similar But one difference has emerged. Waller says that Australian artists appear to have used rock shelters much like parabolic reflectors to focus echoes.

When Waller stood at 30 metres or more from a painted wall, he found that echoes seemed to emanate from the central images. But when he stood any closer, the echoes bounced back too quickly to be distinguished from the original sound. "It's almost spooky," he says. "Where they've drawn a person, and you yell at it, it's like the person is speaking to you."

According to Waller, the best way to appreciate the sophisticated art of our ancient ancestors is to make noise. Unfortunately most people walk right up to a painting and study it from inches away talking in hushed voices," he says. "They never step back and see, or hear, the forest for the trees."

[Note: The original article consistently misspells Waller's name as Wailer.]