About a decade ago I was reading everything I could find on the subject of shamans - scholarship, ethnography, memoirs and journals, literary theory, criticism, archeology, history, new age spirituality, self-help and do-it-yourself manuals...
My conclusion was that, roughly - a shaman is a specialist - usually male - figure found in hunter-gatherer and some other nomadic and simple agricultural societies.
The 'ideal type' of a shaman is characterized by having experiences of contact with the spirit world, or some other unseen world, in states of altered consciousness. Shamans have various functions such as healing ('medicine men'), and providing advice, judgement, understanding.
Shamans seem to be a clear prototype of the creative person and his role in society.
The way that shamans are seemingly marked-out from an early age - chosen-by their nature for their particular role - may provide confirmation that creativity is part of a package of personality traits; such that creativity is something like an innate disposition, a way of relating to the world - and not a thing chosen or deliberately adopted.
Thus a person is a shaman, and shamanism is his destiny; by analogy a person is creative, and creativity is his destiny - and the shamanism/ creativity is a fact: true or not true; although of course each person can choose, and may choose differently, what they do about their nature and destiny.
Now, the category of shaman is a modern, Western conceptualization which unifies disparate figures found in a wide range of tribal situations and from different historical times.
The term was originally Siberian and this may link culturally to Amerindian examples (including among Eskimos/ Inuits, through classic 'Red Indians'/ Native Americans; to Amazonians and Patagonians); but shamans are also instanced among the Bushmen of the Kalahari desert in Africa and Aborigines in Australia; and indeed wherever there is an animistic, or simple totemistic, religion.
However, despite the many fair points made by revisions which tend to suggest that the whole area of shamans is so vague and confused that it would be better to dispense with the term; I believe it does have value.
The key point is that shamans were unexpected figures for anthropologists - found in some types of simple society; but apparently either completely absent from Western societies - or else hidden so deeply as to be undetectable by official investigators.
So anthropologists might expect to find priests, analogous to the already known priests of the Western, Middle Eastern and Far Eastern societies - but shamans are not priests. A new category was needed.
What do shamans do?
My overall impression is that they are called upon to deal with exceptional situations - situations where there is no traditional guidance, or where the traditional guidance has been tried and found to be ineffective.
Such situations could include some types of illness, when and where to move for better hunting, what to do about threats from predators or other tribes, 'legal' judgement in difficult cases - many types of advice and guidance, interpretation and prophecy.
To do this, shamans use altered states of consciousness - trance states of various types or visionary dreams - during which shamans contact the underlying spirit world for information and prediction, or to intervene and change things.
In a nutshell, shamans are believed to be able to come into contact with a deeper level of reality than the everyday - and that is the source of their abilities - and their societal role.
So, the impression from reading many accounts is that shamans are highly creative persons - and therefore I would expect that they would show the Psychoticism-like traits of high creativity; and this seems to be confirmed.
Shamans usually emerge from an early age of life - either childhood or teens; the shaman is either marked from an early age as being different, or else goes through a (typically) traumatic experience of illness, accident or some other stress, which changes them permanently. Thus shamans are flawed, damaged people who also (because of this, not despite it) have special gifts.
The shaman is usually a man - usually not socially integrated, usually lives somewhat apart, may be unfriendly - a person feared and respected rather than loved and cherished.
Often unmarried, without known children - someone who hands on his social role by apprenticeship rather than founding a lineage.
Someone who does not work, but is supported by payments for services and charity/ protection money - at least he does not do work as it applies to the rest of the tribe - hunting gathering, agriculture, warfare, child care...
It would obviously help if the shaman was more-than-usually intelligent as well as more-than-usually creative - but it is probable that these hunter gatherer, nomadic, simple hunter-gatherer societies have not been selected for higher intelligence over hundreds of years - as have some of the more stable and more complex agricultural societies.
So the actual intelligence of real life shamans may have been considerably below what we would consider average - just as the creativity of the average person in the societies they inhabit would be considerably above our average.
By this logic the creativity of a great shaman might have been something quite extraordinary - off the map of our modern, Western understasnding of the possibilities of creativity.
But it is not the exceptional intelligence that sets the shaman apart - rather it is the different cognitive style: the shaman approaches problems differently, or creatively as we would say - he does not apply the usual, traditional, high status or socially sanctioned rules or practices; but instead generates his unpredictable answers using quite different processes and procedures.
And this is something that the shaman cannot help doing: he is made that way, he is called to a role. Most of the time he is not wanted, scary, chaotic, nasty, a nuisance, a parasite - but there are situations when he is needed. and it is for these situations that the shaman is protected by the rest of the tribe.