When investigators of human development have written about “higher” or more adult stages of development they often indicate that such development is spiritual. (p. 3)

Whether we examine moral development, psychosocial development, or midlife individuation, the descriptions of phenomena at these higher stages often contain characteristics that can be interpreted as spiritual. It is as if developmental researchers are finding that human development “naturally” tends toward spiritual development. (p. 3)

If we agree that developmental psychology is a form of science, then we can conclude that science, in another form, has revealed an aspect of spirituality from a new perspective, as others have argued that the physical sciences are revealing truths known to wisdom literatures or cognitive science is uncovering truths long known to Eastern traditions or that psychoanalysis arrived as insights compatible with Zen Buddhism. (p. 4)

If researchers opt for an interactionist theory, and if they also elect to include increasing the depth as well as the breadth of their theoretical reach, then they might turn to a theory that postulates consciousness as the underlying structure that develops over the life span. Socialization is a part of that development, but as the shift of focus changes to the higher reaches of the life span, investigators will have to make room in their theories and models for phenomena that are by no means reducible to socialization. I believe that consciousness is a construct that might enable us to incorporate cognitive development, social development, and spiritual or religious development under one theoretical umbrella. (p. 6)

Irwin, R. (2002). Human development and the spiritual life: How consciousness grows toward transformation. New York: Kluwer Academic/Plenum Publishers.