This article offers a detailed analysis of neurophysiological processes involved in altered states of consciousness. Cross-cultural hypotheses concerning altered states of consciousness are tested.

This article explores ecological, religious, and social correlates of human sacrifice and cannibalism in a cross-cultural sample. Support is found for associations between human sacrifice and population density, population pressure, war for land and resources, and a low hierarchical focus of religion. Human sacrifice among Aztecs is given particular attention.

This article examines shamans and other types of magico-religious healers. Agriculture and political integration are suggested to influence the transformation of shamans into shaman/healers, healers, or possession-trance mediums.

The author builds upon previous research (Winkelman 1998) to further elucidate the cross-cultural predictors of institutionalized human sacrifice. The author considers a range of ecological factors and political variables, particularly geopolitical dynamics and intra- and inter-group relations. Other factors were explored, including social complexity and social structures. The author identifies the lack of an effective superordinate political authority as a main determinant in similar behaviors contemporarily (e.g. suicide bombers, beheadings, public brutality in civil war).

This article offers a detailed analysis of neuropsychopsiological processes involved in altered states of consciousness (ASC) in order to design and evaluate a psychophysiological model of trance states. Cross-cultural hypotheses concerning ASC are tested.

The authors examine the relationship between magico-religious practitioner type and socioeconomic variables in order to present a typology of magico-religious practitioners. Three bases for magico-religious practitioners are discussed in terms of selection procedures and activities. Several hypotheses are empirically tested, and descriptive generalizations derived from analyses are presented.