A new research has suggested that auditory illusions influenced the prehistoric art as there are several ways in which virtual sound images and absorbers can appear supernatural.
Researcher Steven J. Waller said that ancient mythology explained echoes from the mouths of caves as replies from spirits, so the ancestors may have made cave paintings in response to these echoes and their belief that echo spirits inhabited rocky places such as caves or canyons.
Just as light reflection gives an illusion of seeing oneself duplicated in a mirror, sound waves reflecting off a surface are mathematically identical to sound waves emanating from a virtual sound source behind a reflecting plane such as a large cliff face, which can result in an auditory illusion of somebody answering from within the rock.
Waller added that many ancient cultures attributed thunder in the sky to "hoofed thunder gods," so it makes sense that the reverberation within the caves was interpreted as thunder and inspired paintings of those same hoofed thunder gods on cave walls.
Waller continued that this theory is supported by acoustic measurements, which show statistically significant correspondence between the rock art sites and locations with the strongest sound reflection.
He added that sound, which is invisible and has complex properties, can easily lead to auditory illusions of the supernatural, which in turn, leads to the more general question: what other illusions are people living under due to other phenomena that they are currently misinterpreting.