Auditory Illusion

An auditory illusion is an illusion of hearing, the aural equivalent of an optical illusion: the listener hears either sounds which are not present in the stimulus, or "impossible" sounds. Shamans are known for their ability to create unusual auditory phenomena. According to Scottish percussionist Ken Hyder, who has studied with Siberian shamans, "Shamans tend to move around a lot when they are playing, so a listener will hear a lot of changes in the sound ... including a mini-Doppler effect. And if the shaman is singing at the same time, the voice will also change as its vibration plays on the drumhead."1 The Doppler effect can be described as the effect produced by a moving source of sound waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching and an apparent downward shift in frequency for observers from whom the source is receding.

Furthermore, in a recent ethnographic study of Chukchi shamans in northeastern Siberia, it was found that in a confined space, shamans are capable of directing the sound of their voice and drum to different parts of the room. The sounds appear to shift around the room, seemingly on their own. Shamans accomplish this through the use of standing waves, an acoustic phenomenon produced by the interference between sound waves as they reflect between walls. Sound waves either combine or cancel, causing certain resonant frequencies to either intensify or completely disappear. Sound becomes distorted and seems to expand and move about the room as the shaman performs. Moreover, sound can appear to emanate from both outside and inside the body of the listener, a sensation which anthropologists claimed, "could be distinctly uncomfortable and unnerving."2

1. Ken Hyder, Shamanism and Music in Siberia: Drum and Space. Tech. 11 Aug. 2008. Web. 28 Feb. 2012.

2 .Aaron Watson, 2001, “The Sounds of Transformation: Acoustics, Monuments and Ritual in the British Neolithic,” In N. Price (ed.) The Archaeology of Shamanism. London: Routledge. 178-192.