Dr. Clare Graves, whose research was foundational to the formation of Spiral Dynamics, writes, "What I am proposing is that the psychology of the mature human being is an unfolding, oscillating, spiraling process, marked by progressive subordination of older, lower-order behavior systems to newer, higher-order systems as [a human's] existential problems change."  Graves posited, in the words of Don Beck, that the "deeper patterns in the evolution of human consciousness . . . reflect different activation levels of our dynamic neurological equipment." 
I'll own that I am out of my league here, trying to explain neuroscience! But if you'll bear with me, I will give you a layman's summary of what I've learned about "our dynamic neurological equipment." I am fascinated by recent studies of the brain that support Graves' idea that the evolution and growth of the human brain affects our level of consciousness. We need every angle we can find to try to understand ourselves, and even what is happening in history, which often feels so hopeless.
Much of what I'll be sharing about brain research comes from Joseph Chilton Pearce and his book, The Biology of Transcendence. The study of neuroscience and brain development indicates that we are wired for transcendence, for the ever bigger picture, but it is all highly dependent on being exposed to living models and personal nurturance as we move from one stage to the next. Fowler and Kohlberg said the same thing: We all need living models. How important we are for one another! This is a good argument for some form of church community--to gather enlightened, transformed, loving people together so they rub off on one another. Beyond models, we also need nurturing: mothering and fathering, loving, and partnering at the critical stages of brain development, which are almost all in the first twenty-five years of life.
Throughout childhood and adolescence, the individual regions of the brain and the pathways connecting them are still under development. Between the ages of fifteen and the early twenties, excess gray matter and unused neural pathways are pruned to make the brain more efficient. A myelin sheath--like electrical insulation--forms around a nerve to increase the speed of electrical communication between neurons that are being used. In this way, the brain's regions are stabilized and prior brain developments become permanent. It appears that the pruning occurs starting at the back of the brain, moving forward. The prefrontal cortex is the last section to undergo myelination. The prefrontal cortex helps you inhibit impulses, make decisions, make plans, think long-term, achieve goals, and evaluate rewards and risks. Research shows that our human brain is not fully developed until around age twenty-five.
Teens are much more sensitive to peer approval than they were as children or will be as adults. We often see this in teenagers as a desire to do something wonderful, to be someone great, to connect with something momentous. It's actually transcendence they are searching for. But because there aren't living models around them of saints, of mystics, of people who've got the big picture, they settle for rock stars, movie stars, or professional athletes. That's the only greatness offered to them in a secular culture. They will try to become rich or famous, which looks like greatness, and yet it is still inside what I call the false or small self. It is not yet the fully connected self, the Great Self, the God Self.
If, between the ages of fifteen and twenty-five, the young person has both models and enough nurturance (and maybe even an experience of initiation), the visionary, idealistic worldview takes off for the rest of his or her life. That's why such a person is never satisfied and keeps searching for more transcendence, yearning for closer connection with God, with others, and with the universe. I hope you know such a person. They are the prime movers for all of us.
If during this early period there are no strong models or wisdom elders, the prefrontal cortex does not keep the neural pathways for transcendence active and accessible. The young person becomes just the opposite: cynical and negative, with a deep, cosmic disappointment that this greatness will not happen to them. "I'm not part of something momentous," he or she concludes. "I'm just dumb old me." So to give oneself significance they may compete on a music or dance show or even join ISIS--anything big and noisy. Pearce says this is what we see in many Western teenagers today, because we haven't offered them anything greater or deeper--or within.
Pearce suggests many young people even revert to earlier levels of brain development because their disappointment is so great. Some revert to the reptilian brain where they only react to life in terms of freeze, fight, or flight. That type of person divides the world into simplistic good guys and bad guys. We call this dualistic thinking, or "all or nothing thinking." There is no ability to subtly read the soul. This is the character of many politicians, preachers, and people attracted to a kind of religion that affirms their good buy/bad guy worldview and takes away their inner anxiety.
Hopefully life and God bring new opportunities--through experiences of great suffering and great love--to "rewire" our brains even if we have not experienced the nurturing and guidance we needed at key stages.