The Shamans used and still use a variety of techniques to achieve the trance state.
Among them were, prolonged dancing, fasting and chanting. This last, incidentally, was not ordinary chanting. A large choir of Russian Orthodox monks sounds like a tin whistle with the croup, in comparison with a Shaman in full voice.
There are a few sounds in the world, more unearthly then the vocal performance of a Siberian Shaman, as he prepares to leave the mundane world. Bizarre but distinct whistling come down from his sinuses, and out of his nose and mouth. While he uses and astonishing fundamental muscular control to produce a grim low rhythmic roaring from the diaphragm. On top of these various noises, he menages to produce a conventional human chant (or mantra) often of eerie beauty.
Shamans may use other ritual tools at the same time or separately to induce trance. They include exposure to extremes of heat or cold, and a range of more or less horrifying methods of inducing pain, and hence, sensory deprivation. Shamans may also use hallucinogenic plants, foods or smoking mixtures ('the peace pipe', had a number of applications, but the ultimate effect was usually very peaceful).
The hallucinogens that the Shaman's used are interesting because many of these drugs gave their user a strong impression of flying (hence., the nowadays implication of the word -'high' when ingesting or inhaling drugs).
Most of the people don't realize what is actually happening when we're hallucinating. The drugs affect the Pineal Gland, and from being calcified, it opens up, and goes totally wild, and uncontrollably produces it's hormones (DMT (Dimethiltryptamine), Melatonin and Serotonin...).
You can get more information on that in these previous posts:
One 19th century explorer into the South American interior, described how he felt himself going on an aerial journey, as a result of drinking Ayahuesaka, a potent Indian tincture made from a hallucinogenic vine. The mental imagery induced by drug use and trance became central to many tribes' art. Among the rock paintings in a Chumash, Indian Shrine, at Burro Flats , near Los Angeles, there is a series of geometric forms, dots, lines, crosses, circles and concentric rings. Similar patterns are found in rock art all over the world, and can be seen carved into the rock at many megalithic sites in Britain. The source of these patterns is the human brain. The Tukano Indians of Columbia in South America (who use trance inducing drugs in religious ceremonies) imploy similar imagery as a basis for the decorative work on their pottery and clothing, and freely admit that these are based on the colorful, but geometric forms (sacred geometry?) they see under the influence of drugs.
The San (Bushmen) of the Kalahari, too, make no secret of the fact that the patterns and motifs in their own rock paintings are based on what their Shamans see when in Trance. These patterns were probably the original inspiration for another enigmatic pattern found at endless numbers of sacred sites all over the world: the labyrinth, or maze.
Most significantly, the Shaman moved from normal awareness to the 'Otherworld' to the endless beating of a magic drum, which was covered in signs and symbols to protect him on his esoteric journey elsewhere. He called his drum - his Steed, or Canoe, on or in which he would travel to the Spirit Realm. One of the more intriguing discoveries made about these drums is that they produce sounds at extremely low frequencies. As few as four circles per second, these affect the - Theta brain wave frequencies - Frequencies of the brain, when the mind is in deep meditation/deep sleep. In the Siberian tribes, the shell of the Shaman's drum was said to be made from a branch of the 'world tree' (usually in fact, a birch). Because of this magical link a trough his hypnotic drumming, the Shaman is projected into the vicinity of the Tree.
In the tribes of central and northern Asia, the Shaman would actually climb a birch tree during his trance, to show his spectators that he was indeed ascending the axis of the world, and passing into the realm of spirit.
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