As for factors related to spiritual development per se, psychologists generally agree that the average child's religious and moral development progresses along a series of what appear to be universal stages, starting with individual predilections and culminating in abstract principles that apply to all peoples at all times. Such stages parallel cognitive growth in general. However, until wider and deeper sampling across non-Western societies is conducted, the question of the universality of such a series still remains open. It is during adolescence that many youth seek spiritual guidance to what they feel (and perhaps already know in a less sophisticated fashion) to be a transcendent entity. Such guidance may be supplied by teachers of religions practiced in cultures other than their own or by charismatic figures that have made an emotional impression on them. And this impression can be very strong, as we can see from the powerfully motivated, often self-sacrificial, behavior of many young religious adults politically active today on the world's scene.
In-depth and representative studies covering life-span development of spirituality in individuals still have to be done. Surely many clergy, spiritual masters, teachers, and parents interested in children's spiritual life possess a wealth of information that could aid us in better understanding such development. But this wealth of information has not yet been systematically documented and collated for scholarly examination.
Whatever understanding we now have, there is no question that spirituality has most likely been part of the human condition for as long as humans have existed. We can infer this from prehistorical burial remains and cave paintings. Despite the demanding physical conditions of Pleistocene life, our distant ancestors still managed to be concerned with things unseen. A good example of this is burial customs in which valuable material goods are placed in the graves of the deceased. The widespread existence of such customs is remarkable given that our primitive ancestors must have surely been aware of the fact that burial costs entail valuable resources and time, all of which have to be borne by members of their group. However, perhaps just because the world at the time was so demanding and perilous for early humans, imagining and hoping for a better life in some other place may well have made suffering and death more bearable. Clearly, wanting to make contact with the unseen and exploring the possibility of life after death- activities that net no known material advantage-has a unique place in a world dominated by material concerns. The universal presence of spirituality attests to a rather peculiar power inherent in the human mind, one which materialists can not wholly deny and which sages, saints, and seers have long known as a given of human nature. With care, this power could be cultivated (one would hope) into something of great value for individuals as well as for communities whose members share the same religious beliefs. While we have little evidence at present to justify hope for a successful cultivation of spirituality in all humans, we know for certain that spiritual insights can create inner peace (many saints and masters), help moderate social conflict (Gandhi), and, by virtue of the asceticism associated with them (St. Francis of Assisi), help preserve the physical world. One could argue that precisely because spiritual experiences strengthen human communities and do not exhaust the world's resources, spiritually guided families will increase in number and their genes will spread throughout increasingly more of humanity. If this happens at a widespread enough level, the world could become a more habitable place for everyone.