15 Consciousness

Some people report feeling as though they are floating weightlessly above the bed during the hypnagogic period.

How do different levels of consciousness function?

• During minimal consciousness, we only dimly perceive the environment and might respond to a stimulus without full awareness of it (for example, during sleep).
• During full consciousness, we are aware of our environment and of our own thoughts and mental state.
• Self-consciousness is the highest level of consciousness; it enables us to reflect on our own identity.

How does consciousness change while we sleep and dream, and why?

• The body’s circadian rhythm controls sleep patterns.
• The sleep cycle consists of several stages. Stage1 is a very short period characterized by slow breathing and irregular brain waves, Stage 2 is a brief period characterized by burst of brain activity, and Stages 3 and 4 are longer periods of deep sleep.•Meditation is a process by which people can achieve a state of deep mental calm through concentration or mindfulness.
• After we complete Stage 4 sleep, we cycle back through Stage 3 and 2 sleep and enter REM sleep, in which heart rate and breathing increase and brain waves become fast and irregular.
• This cycle occurs every 90 minutes throughout the night. Stage 3 and 4 sleep periods decrease in length and eventually disappear, while REM sleep periods lengthen over the course of the night.

How can hypnosis and meditation alter consciousness?

• Hypnosis is an altered state of consciousness achieved through social interaction. It may cause dissociation, a split in consciousness that allows some simultaneous thoughts and behaviors to occur separately from others.
• Meditation is a process by which people can achieve a state of deep mental calm through concentration or mindfulness.