<P> Their return into psychology began with Wiliam James' interest into a variety of altered states, such as "mystical experiences and drug - induced states". James' investigations into first - person - subjective - experience contributed to the reconsideration of introspection as a valuable research method in the academic community . </P> <P> The social change of the turbulent 1960s has decisively led to a change of the scientific perspective to the point that introspection as a scientific method and ASCs as valid realms of experience became more widely accepted . Foundations for the research have been laid out by various scientists such as Abraham Maslow, Walter N. Pahnke, Stanislav Grof and Charles Tart . They focused on seemingly beneficial aspects of ASCs such as their potential to "promote creativity or treat addiction". Rather oppressive states such as dissociation from trauma were neglected . </P> <P> The findings of the famous Good Friday Experiment by Pahnke suggest that mystical experiences can be triggered by psilocybin . Later investigations by Rick Doblin found that participants valued those experiences as "spiritual high points of their lives". </P> <P> In the midst of the rise of new - age subculture Stanislav Grof and others formed the new field of transpersonal psychology, which emphasized "the importance of individual human experience, validity of mystical and spiritual experience, interconnectedness of self with others and the world and potential of self - transformation". </P>

Alternate states of consciousness (ascs) can be achieved in which of the following ways