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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.’