Spirituality and Western Psychology
Just as for their colleagues in the other sciences, most mainstream psychologists disavow anything that they can not readily measure or deal with. So the spiritual side of our nature is not a major research priority. Prospects are brighter here though, since many psychotherapists and psychiatrists have some interest in these things. Transpersonal Psychology and Humanistic Psychology are legitimate branches that openly include dealing with human spiritual experience as part of their helping practices. Beyond this, research by cognitive scientists into brain structure and function can help to shed modern understanding on some features of spiritual experience.

Humanistic and Transpersonal Psychology
Psychology has traditionally dealt with restoring imbalanced mental function to a more normal condition. It has paid very little attention to the idea of human potential--that is, to what humans can grow towards and become. In the last several decades, however, this narrow focus has shifted somewhat to also consider and support the psychological growth of people who are basically well-adjusted. In particular, the area now known as Humanistic Psychology has most thoroughly incorporated this attitude of the possibility for human actualisation into its practice. A classic presentation of these ideas is embodied in the following "hierarchy of needs" that was developed by the humanistic psychologist, Abraham Maslow.
1. Physiological
2. Safety
3. Belonging
4. Self-Esteem
5. Self-Actualization
6. Self-Transcendence
Each need builds upon its more basic neighbours. So, needs for safety can be adequately met only after one has met one's physiological needs such as food and sleep. Likewise, the wish to belong in a relation, a family, an organisation, a culture, or a society, necessarily requires that one has realised a level of safety. By adequately satisfying the demands of a level, we are more fully freed to pursue issues relating to higher levels of self-expression and communication. Self-esteem, the liking and acceptance of oneself by oneself, is a pivotal level in the enfoldment of human awareness. With it, we are enabled to weather the stormy seasons of daily life; without it, we are lost ships at sea. By believing in the basic goodness of ourselves, we can allow ourselves to grow and blossom. If we don't fundamentally accept our own spirit, then we shall have little cause to support activities that can help us. Once, the landmark of self-acceptance has been secured, a person can work to achieve interesting and meaningful goals. Such purposeful and consistent effort will, in time, be successful and result in self-actualisation, the shaping of one's life to accord with one's highest values and goals.
Humanistic Psychology substantially ends at the upper reaches of self-actualisation--a level which is assumed the summit of personal growth by most cultures. It is Transpersonal Psychology which continues this sequence by exploring what might lie beyond these socially constructed bounds. The subsequent level of self-transcendence encompasses the common mystical experiences of all the world's spiritual paths. Thus, these relatively new disciplines, see the human saga as one of natural enfoldment--one which reaches from solely personal achievements of well-being and success through to transpersonal achievements of universal wisdom and compassion, spiritual insight, and enlightenment.
Psychological Metaphors for Spiritual Reality
An abundance of research into brain function is available that can help to explain human spiritual experience in broad terms. Spirituality can be considered from three distinct views--personal subjective experience, the social forces and expectations that colour personal interpretation of events, and the brain structure and function that underlie mental and spiritual processes.
Subjective Experience
One of the key results from cognitive psychology is that our perception of life is subjective. We colour what we experience by the current state and mood that we are in. This result can be extended along metaphysical lines. Normally we take "subjective" to mean what we think and feel in our mind and body; similarly, "objective" means what happens outside the boundary of our body and what we can not experience in our mind. As a student reaches advanced levels of spiritual realisation it regularly happens that she or he finds the "subjective" expanding to include parts of the "objective". Many psychic phenomena such as telepathy, clairvoyance, psychokinesis, and faith healing can be included in this effect.
At very advanced levels attained by spiritual masters who include deep concentration in their training, the "subjective" becomes practically synonymous with the "objective". Such masters appear to suffer little hindrance in their access to "objective" information and control. In effect they have powers that religion and folklore normally associate with gods. Yet these masters, are simply people who have developed a special side of their innate human nature. And for all their amazing abilities, they still are aware of the normal distinction between subjective and objective, and they consistently honour that distinction for the benefit of those who still take the "objective" as being something wholly outside of themselves.
Social Forces Affecting Spiritual Experience
It is often the case that serious practitioners will have their mystical experiences flavoured by the religious and social conditioning that they have brought with them to their spiritual practices. For example, a Hindu ascetic might have a vision of Krishna or Shiva while in deep meditation, whereas a Christian monk might experience the presence of Jesus or Mary while in deep prayer. At beginning levels of practice this can be understood as an extension of normal subjectivity. But as the "subjective" becomes the "objective" for very advanced aspirants, the same multiplicity still seems to hold sway. This may imply that the deeper, associative levels of existence can accommodate multiple, overlapping "subjective" and "objective" realities. So for instance, instead of there being only one heaven and there being only one religion that is right, in fact there is a more subtle level that is basically neutral to opinion but amenable to concentrated levels of consciousness. And this level can be written upon by the mind of an advanced soul or the group mind of a people's beliefs. It is like the canvas that an artist uses to paint a picture on. In this way, the next more subtle level than this earthly level can house a multitude of heavens and other realms.
Structure of the Brain
There are various lanes available for understanding the interaction between brain and spiritual experience. Some of them are the left-right brain dichotomy, the functional layering of the brain, the visual system used as a hemispheric bridge, the sequential processing of perception, and the evolution of awareness.
Left and Right Brain
The brain can be taken as having two hemispheres, a right side and a left side. For most humans, the left side is tied to language and the right more to visual perception, imagery, and emotion. The left side of the brain specialised for language over the course of millions of years of evolution and some of its previous function is now basically operational on the right side. The main feature of the right--or earlier--side of the brain is its emphasis on holistic processing. That is, it shows marked superiority to the left side in many experiments that consider context more than detail. In essence, it handles the "big picture" much better than the left brain does. In contrast, the left side has specialised in detail. This extends, in fact, to partwise representation of images--the left side consistently scores better than the right side in tests where image detail is being measured.
There are many other differences between the sides as well. The left side, for instance, is the main side for all temporal processing. That is, it directs and coordinates our activities that stretch out over time. The left side is also more associated with positive emotions and perception of rhythm. The right side, has an advantage in spatial attention, visual rotation of images, and recognition of musical aspects such as melody, pitch, timbre, and harmony. Also, along with being more associated with negative emotions, the right brain seems to be the governor and have overall control of the emotions.
Three-Tiered Brain
The brain can also be taken as three-tiered. The most primal level resides at the bottom and deals with aggression, herd instincts, reproduction, and basic metabolic processes. In terms of evolution this part reaches up to the level of reptile development. The next major area is the middle tier, which houses the parenting instincts, the ability to play, judgements of pain and pleasure, and the emotions. It reaches to the level of mammals. Finally, the upper tier houses language, the sense of self ( ego ), the ability to take on other's viewpoints and understand their experiences, and the skills required to think and plan. This reaches up through the level of higher primates, such as the chimpanzee, to the level of humans.
Visual System
A third system to consider is the visual system which has two parts functioning somewhat in analog to the right ( old ) and left ( new ) split of the hemispheres. The ancient visual part detects motion; it does not recognise colour well; and takes in data from the periphery of the visual field. Some spiritual practices ( Dzogchen "big sky" meditation for example ) make use of this system to reach deep into the primal layers of the mind. The more recent visual function is that of analysing detail. It recognises subtle nuances of shade and colour and is oriented towards steady focus upon an object. Visual meditations that focus upon a symbol such as a yantra or mandala, directly use this newer system as their basis. Because the visual system tends to span both hemispheres, it is used in tantric practices to effect the integration of wisdom--the right brain experience of emptiness ( non-identification with the left brain ego ) and bliss--the left brain experience of deep concentration.
Five Skandhas from Buddhist Psychology
Several thousand years ago, Buddhist teachers first explained awareness in terms of five sequential mental operations. Modern research has tended to corroborate these early findings. The first step is contact with raw sensation such as tastes and sounds. These initial imprints are next decoded by the emotional centre in the middle tier of the brain. This centre decides whether a sensation is pleasurable or painful. The third step occurs in the upper tier when associative thinking further identifies the basic emotional signal. A pleasant touch, for example, might be correlated with some other memory: "Oh, what a good feeling, it reminds me of sitting on the porch when I was a child." The fourth stage, is the full-scale mental elaboration of the identified occurrence. This stage includes mental reflection, planning, and expression of personality. This level of thought bundled with feeling is the hallmark of personal identity and it is taken for granted by most of us that communication and expression at this level is what being human is all about. The fifth level is one of direct awareness--it does not include self-reflection in terms of thinking. This stage is similar to what is called bare awareness in the tradition of Vipassana meditation. It is simply an awareness of whatever comes into the field of one's experience. There is a subtle sense in which this awareness knows of itself, but it is different than the way the ego knows of itself through a combination of thoughts, emotions, and sensations. Rather, this awareness recognises itself via subtle energies and the associative nature of deeper levels of reality.
Evolution of Consciousness
Combining the tiered and left-right models gives the following sketch. Our distant ancestors used mostly implicit forms of cognition. These were instinctual and habitual patterns of action that enhanced their chances for survival. Actions and mannerisms that succeeded in this task, were perpetuated and hence, accentuated. Since then, humans have gradually evolved from dealing only with such basic survival issues to more abstract social problems. This reflects the ascendancy of the left brain. Its ability to represent discrete episodes and events produced the needed fuel for language and civilisation to spring forth. As a species, we are now captives of our thoughts. Our cultures and values revolve around the self or ego which is a by-product of left brain function. And the left-brain runs riot with thoughts. It is constantly generating both wanted and unwanted thoughts and ideas which in turn key in their corresponding emotions and sensations. Early in human evolution this may have been a useful skill for survival. By having the mind ever on the move, it would have been easier to remain alert for changing conditions in the surroundings such as the approach of a tiger.
The self, or ego, results from the self-reference of this endless torrent of thought. What we commonly hold as our sense of self is, upon closer inspection, found to be groupings or bundles of thought, feeling, and sensation. That is, the ego is a temporal effect of the left-brain's ability to think about itself. At any given moment, the ego is a collection of present and recent mental, emotional, and sensory cues to oneself. Metaphorically what happens is this, the ego needs to know that it is still ok and intact so it says to itself "I think and feel this about that", and then it waits listening. The next instance certain emotions and thoughts naturally arise in response to the comment. The ego hears and feels them and says, "Ah, good, good, I'm still here and things are about the same as they were just a little while ago." These bundles of feedback to the ego are rather like smeared or blended groupings of experience. It is the constant rush of these signals of "its ok, I'm still thinking, feeling, and moving about", that constitutes the ego. In effect the ego is a left-brain artefact.
To summarise, mental function rides on a sea of incessant, random thought. Normally, we have very little control over this tumult and hence are prey to its chaotic nature. Our subjective experience of this is filtered or smoothed somewhat so that we experience a more stable mental climate. But a certain level of this noise spills over into our mentality. It is an open question whether this is good or bad, but the actual track record of human culture throughout history shows that personal consciousness which progresses no further than this level is, on average, at best a lead-in to instability and harm at the social level. The endless wars, crimes, misery, and misunderstanding that are our inheritance are ample witness to this fact.
Tests with split brain patients have shown that both sides of the brain can have separate consciousness. A further step in human evolution is the reintegration of the older right-brain wisdoms into our thoroughly left-brain saturated society. This harmonisation of left and right brain activity leads to a balanced human perspective which upholds the needs of both individual and group. In metaphysical circles an even further step is the reintegration of spirit ( the soul ) with the body, heart, and mind.
In fact, Buddhism has observed for millennia that normal, adult psychology and behaviour only partially fulfils its potential. The ability to move beyond the limited bounds of personality and ego has been scarcely acquiesced, much less attempted, by the average person. It is just as hard, though, to lead a partially fulfilled life as it is to steer to one that is mostly self-actualised. This amazing fact results from the power of unconscious conditioning. A power that sets the course for all of our actions.
The Unconscious Mind
Modern academic psychology recognises two distinct types of memory and action, explicit and implicit. Explicit activities are those that we can consciously experience and direct. In contrast, implicit activities are more automatic and do not interact with the ordinary waking mind. Popular psychology takes this one step further and posits the existence of a semi-autonomous unconscious mind that in part is responsible for much of human implicit behaviour. Mostly in agreement with this popular notion, mystical teachings do, however, vary on the amount of emphasis they place on the autonomy of the unconscious mind. Nevertheless, they all underscore the great importance of learning to harness its power. Habits are prime examples of implicit actions. It is no exaggeration to say that they can easily make or break a person's chances for happiness in this life. Thus, mystic teachings are in accord with pop psychology in stating that much of the decision for the outcomes in one's life rests on one's own shoulders. What we think, say, and believe do have enormous pull in shaping the course of our lives.
The preliminary stages of all spiritual traditions are primarily oriented toward reworking the way in which an aspirant thinks and believes. In short, their goal is to remove bad mental habits such as anger, fear, greed, and dullness, and instill better ones such as consideration, courage, equanimity, and determination. All these mind states are simply habits that have been etched into the implicit ( unconscious ) mind through the force of repetition. That is, when something occurs again and again, it becomes ingrained into our nature. And as we all know, once a habit is in place, it takes some real work to change it. The key to such change is knowing that habits are impersonal. That is, they were developed through a mechanistic process and so they can be reworked or overwritten through just the same mechanistic process.
The unconscious mind ( as well as the deeper layers of reality ) does not play favourites. This means that we, as individuals, are responsible for our own well-being and the well-being of others. All mystical teachings emphasise this fact. A secular catchword from the Hindu tradition goes: "Your efforts count for 25%, your spiritual teacher's efforts on your behalf count for 25%, and God's gracious acceptance of you counts for 50%." This is a classic spiritual attitude. It accepts that without the Divine, nothing can happen, but that we also have responsibilities to act in a mature fashion.