Hypnagogia is the collective term for the hallucinations (sights, sounds and other sensations) we experience during the transition between wakefulness and sleep. It occurs at the threshold of consciousness, and is responsible for the onset of lucid dreams, hallucinations, out of body experiences and sleep paralysis. You can deliberately induce hypnagogic hallucinations as you fall asleep in order to have a Wake Induced Lucid Dream or OBE.
Like dreams, hypnagogic hallucinations can be quite random in nature. Here are some of the most common types you will probably have experienced yourself at some time:
The beginnings of visual hallucinations occur as phosphenes - seemingly random speckles, lines or geometric patterns that may float around or remain still behind your closed eyelids. When deeply immersed, you can control these patterns at will. First, just focus on changing the direction of the lines. Then ask for specific shapes and movements. After that it's not difficult to have the phosphenes form a familiar face or animal. By learning to interact with your visual hypnagogia, you should find it easier to transition the visuals into whole imagined scenes which then become lucid dreams.
Occasionally you will experience an auditory hallucinations. The intensity can vary greatly, from faint impressions to loud buzzing noises frequently reported at the onset of an OBE. Auditory hypnagogia range from hearing someone call your name, to hearing the phone ring or snippets of speech appearing to come from very nearby.
I find this kind of hallucination is more transitory and I will only hear a brief few words or have a memory of hearing something just a moment ago. Unlike the visual stuff, the sounds can't really be controlled (in my experience) simply because they're so fleeting. However it may be worth experimenting if you hear drawn out sounds such as music to see if it can be controlled.
This is a truly bizarre feature of hypnagogia, where you feel the sensation of acting out a repetitive activity from the day before.
When I worked on a supermarket checkout, I used to have the frustrating sensation that I was scanning food items over and over in my hypnagogic state. Similarly, waiters and waitresses report having "Server Dreams" where they restlessly wait tables as they fall asleep. Chess players claim to see the checkered black-and-white chess board, and boaties have the sensation of being at sea when they go to bed on solid ground.
Remember, though, this is not a dream state; the brain is using a variety of sensory memories to hypnotize you into a sleep state, where the real dreams can begin.
Although unusual, both lucid dreamers and regular dreamers can experience sleep paralysis at any time. It involves the sensation of being paralyzed (though really we are all paralyzed as we sleep at night to prevent us acting out our dreams) and this natural bodily process is called REM atonia. In this instance however, you are aware of the paralysis and it can be quite scary.
The phenomenon usually passes in a few minutes as you return to full wakefulness or deepen the sensation and step your mind into a lucid dream. Sleep paralysis can be accompanied by loud humming, roaring and buzzing noises (just like OBEs) and in severe cases includes visual hallucinations.
The effects of hypnagogia don't end there. Some people report fleeting sensations of taste, smell, heat and other tactile feelings as they fall asleep. It's also normal to have changes in perceived body size, or floating limbs; sometimes as I fall asleep or meditate I feel as though my arms are in a totally different positions to reality. And we have all experienced the Hypnic Jerk - a sudden jolt back to reality from the verge of sleep, usually accompanied by a vision of tripping or falling (Inception called this The Kick).
There may also be a form of synasthesia at play during the hypnagogic state. Hearing a real-life sound may result in seeing a flash of white light due to some funny cross-wiring in the brain. It's actually thought that we all have some degree of synasthesia in waking life; while most of us may have a spacial recognition of the days of the week in our mind's eye, extreme synasthesiasts see numbers as colors, or taste different foods when they hear certain words.
If you're reading this page and wondering what the heck I'm on about, then you must fall asleep before the onset of your hypnagogia. This means you don't consciously observe it and so you won't have any memory of it at all.
Don't worry. Some nights, I go straight to sleep without giving it a second thought and I still have spontaneous lucid dreams later on the same night. However, it can be helpful to induce conscious hypnagogia for two reasons:
First, go to bed at your usual time and relax.
This will bring on the hypnagogic state, provided you don't fall asleep first. To ensure your brain stays consciously alert, try focusing your awareness as you breathe in, and then relaxing your body further as you breathe out. You body really must be relaxed, so actively relieve all tension by squeezing and then releasing all muscle groups.
If you feel the urge to roll over, good! This is your brain sending a signal to your body: are you asleep yet? Resist that urge and stay relaxed, and you should begin to experience some serious hypnagogia. Do not worry about sleep paralysis. Most of the time I don't feel it because my awareness is directed well away from my body. If you do feel the paralysis rolling up your body, just go with it deeper, and start to visualize your next lucid dream. You are so close to attaining full lucidity inside the dream world!
If you lay still for about 15 minutes and still can't see any blobs of color or twinkling lights, then your brain is probably too active and alert to sleep. Listen to some brainwave entrainment to achieve an alpha and then theta state of awareness and you will be guaranteed to experience some hypnagogic magic. I experience visual and sensory effects every time I listen to my entrainment MP3 and it leads me into a deep meditation, from which point I am ready to launch my lucid dreams and OBEs at will.