According to the book I’m reading, What Really Matters: The Search for Wisdom in America, many of the biofeedback pioneers viewed the early focus on training people to experience the alpha range of brain waves as a mistake. Elmer Green, biofeedback pioneer said,

Alpha is finally only an idling state. It’s ten times better than beta when you’re tense, but beyond a certain level of relaxation, it doesn’t have that much to offer by itself. If you want to truly grow, the only way you’re going to do that is through the deeper state of theta. That’s where you can interrogate the unconscious and even gain the ability to reprogram it. The true value of alpha is that it’s a necessary bridge between beta and theta.

Green did research on theta in the early 1970s. Neurofeedback studies of yogis and monks showed that as they moved into deep levels of meditation, alpha eventually gave way to long trains of theta waves. Zen masters have described this deep state as having access to some deeper level of truth or knowing.

The challenge is to learn how to experience theta without falling asleep. Our most common experience of a pure theta state is in those moments when we are falling asleep or awakening, when our minds let go of rational thought and often spontaneously form images.

We found theta to be associated with a deeply internalized state. The state of deep quietness of body, emotions, and mind…achieved in theta training seems to build a bridge between conscious and unconscious processes and allows usually “unheard” things to come to consciousness. It’s as if you have two radio signals. One is loud, the other is very soft and faint. To hear the faint one, you have to turn the loud one down. We go into theta to get this loud noise of normal waking consciousness turned off, so we can hear the softer voice underneath. And we do that because the breadth of our consciousness turns out to extend far beyond what we’re usually conscious of.

The book goes on to relate studies done by Green and associates where they trained themselves and others to relax the body, quiet the mind, let go of emotional tension, and increase theta while remaining awake enough to be aware of the imagery that arose.

College students so trained were able to recall rich imagery, including long-forgotten childhood events. After the studies, a significant percentage of students reported positive changes, including greater clarity, more energy, improved relationships, and better concentration and recall.

Green went to India to study brain wave patterns of advanced yogis and tested Ram Sharma, who could produce nearly pure theta waves on command while remaining fully conscious, unheard of in the West.

Green later said the value of theta training…

…is the relatively rapid development of a skill in shifting, without years of trial-and-error meditation, into a state of consciousness in which one comes face to face with one’s Self…. You can feel all the mental, physical, and emotional things going on around you and in you and yet not be identified with the individual pieces.

So how can you experience theta without a neurofeedback machine? I’ve experienced it when receiving cranio-sacral therapy, esoteric acupuncture, regular acupuncture, and massage, and also through meditation.

Once experienced, it becomes easier to re-experience.