In my most recent article I look at the way in which shamanic influences show up in fairy tales, particularly the new TV shows Once Upon a Time and Grimm. That piece left shamanism as a more general phenonemon, but it might be helpful to do a little advanced parsing with some help from Ken Wilber's integral theory.
In Wilber's work there is the distinction between states of consciousness and structures (or stages) of consciousness. A great book of Wilber's on this subject is Up From Eden. Structures are, in part, major human epochs or worldviews. Jean Gebser had the pattern as: archaic, magical, mythic, rational, and (the coming) integral-aperspectival. States, on the other hand, are freely available at all times. There are also individual developmental structures of consciousness--as charted, for example, in developmental psychology.
In Wilber's work, there is the notion of four great states of consciousness: gross, subtle, causal, and nondual. For Wilber each of these states has a characteristic form of mystical awareness: gross is nature mysticism, subtle is deity mysticism, causal is formless mysticism, and nondual is Isness.
For Wilber (along with Alan Combs), the states are interpreted and embodied through the stages. This creates what they call the Wilber-Combs Matrix (or Lattice--pictured to the right).
Generally shamanism is categorized as a form of nature mysticism and arose during the magical structure of consciousness. And there's good reasons for doing so--though there are limitations to this approach as well. Namely that however much it is helpful to conceptually distinguish states from structures, the two are always enmeshed in each other in profound ways.
When we say nature mysticism, we mean mystically uniting with the waking world of experience. Shamans, in their journeys, use imagery drawn from this world: travelling to the underworld via canoe, climbing to the heavens via a tree, being led by a spirit animal, and so on. The tradition of shamanism in the Americas knew a version of what we would recognize as the chakra system from India. Usually people talk about 7 chakras (as pictured to the left), going from the root base of the body to the crown (top of the head). The 7th chakra, however, in some traditions is said to open up to another reality of many other phenomena and truths. In other words, the 7th chakra might be thought of as the source of the nature mysticism: it is the gateway between the waking world of normal consciousness and the subtle world of dreams and visions. This is how shamanism is normally seen, reaching the 7th chakra as the final point of mysticism in relation to the gross, waking world.
But as shaman and scholar Alberto Villoldo points out, he was taught a shamanic tradition of an 8th and 9th chakras. The 8th chakra, what his South American shamans called the wiracocha, was up above the top of the head, a good foot or so above the head. It is the place of halos (on saints) in religious iconography around the world. The 8th chakra is the home of subtle consciousness--it transcends the gross world of waking existence in visions. This is the realm of saints and mystics seeing visions of God, Angels, Buddha, or the Light. They may also hear subtle sounds. The 8th chakra, the wiracocha, is depicted in this South American shamanic tradition, as golden--again think halos.
The 9th chakra that Villoldo was taught by his shaman masters was said to be black. This is causal or formless mysticism. There are no more images--either from the mystical world of nature nor the heavenly world of the deity forms. The darkness is not the loss of consciousness as in "blacking out", but rather the entrance into super-consciousness. The causal is a form of consciousness so refined that there is no self there to register it. There is no self-consciousness then and therefore no sense of time or space--this is why the causal is said to be an experience of the Infinite and Eternal. The Christian mystic Dionysius called the causal, "luminous darkness" or "dazzling darkness."
So while shamanism is typically placed in the more nature (or gross) mysticism realm, Villoldo's work shows that shamanism has, at minimum, the capacity to reach into the causal realms. This is important because many of the causal spiritual traditions tend to deny the value of the gross and subtle forms of experience, so this system of the 9 chakras could be a very helpful way of developing through all three great realms: gross, subtle, and causal. This way we can see the value and limitations of each.
Last image is by Nicholas Hughes.