This is a mouthful. But it is true. And it poses one of the biggest problems for all sciences. One can make a good argument for the case that studying the developing human is more difficult than studying the formation of the universe. Major elements of the universe are in every human, but put together in such a complex (one could say miraculous) way, it is possible we will never know completely how humans come to be what they are. Fortunately, psychologists such as Piaget and Erikson have contributed valuable ideas and observations on how religious ideas (not necessarily spirituality) develop over time. Their insights as well as those of William James and Fowler are among the first to investigate the true nature of this dynamic interaction.
We assume that this interaction begins in the first days of life. At present, we cannot say for certain, however, when a child first becomes spiritual. Most newborns appear conscious of persistent or sudden, novel stimulation such as gastrointestinal pain or a loud noise. Some months after birth, the repeated speech sounds and behavior made by others appear to have a cumulative impact upon the infant's consciousness as indicated by observable signs of awareness and expectation in the infant.
During toddlerhood, children begin talking about unseen entities (monsters, ghosts, scary people), entities that they have probably heard about from adults and siblings. It is conceivable that these experiences are the developmental forerunners of later beliefs in spiritual beings. As for possible general cognitive mechanisms responsible for such experiences, child psychologists agree that toddler and preschooler assimilate what they hear from others to their own thoughts. Young children often talk about God and ghosts, say prayers with gusto, and not infrequently ask questions about things not seen.
Developmental psychologists have discovered that the thought of school-age children rapidly becomes enriched as a result of both formal instruction and everyday experience. With age, moral and religious beliefs become more cognitively elaborated and abstract. While cognitive growth during the school years is directly affected by outside influences, children also react on the basis of personal preferences and experiences-some listen eagerly to religious talk, some not at all; and some distort whatever is said to them. As many adults, children tend both to absorb what they hear and read by way of their preferences and recently acquired idiosyncratic filters. Unlike many adults, though, they also tend to faithfully mimic the words and behavior of those around them. They can often memorize prayers and perform simple religious rituals seemingly without effort. Whether spiritual thoughts and feelings accompany such behavior is another matter.
For certain, spirituality in late adolescence and early adulthood is influenced greatly by education and by religious and spiritual models. For many adolescents (at least in most Western cultures), questioning religious and moral norms is frequently undertaken in earnest. Many seek more elaborate reasons about why they should believe or not believe what they have learned when they were younger. Once again reactions to these answers are contingent not only on earlier cultural experiences, but also on the child's innate as well as learned interests and prejudices.