Our lives involve regular, dramatic changes in the degree to which we are aware of our surroundings and our internal states. While awake, we often feel alert and aware of the many important things going on around us. Our experiences change dramatically while we are in deep sleep and again when we are dreaming. Some people also experience altered states of consciousness through meditation, hypnosis, trances, or by using alcohol and other drugs.

This chapter will discuss states of consciousness with a particular emphasis on sleep. The different stages of sleep will be identified, and sleep disorders will be described. The chapter will close with discussions of altered states of consciousness produced by hypnosis, meditation, drugs, and trance-like states.

Learning Objectives

• Describe what is meant by consciousness
• Explain how circadian rhythms are involved in regulating the sleep-wake cycle, and how circadian cycles can be disrupted
• Discuss the consequences of having a sleep debt and who is most likely to have them
• Describe areas of the brain and the hormones involved in sleep
• Describe theories aimed at explaining the function of sleep, and why we dream
• Describe the different stages of sleep
• Explain the role that REM and non-REM sleep play in learning and memory
• Describe the symptoms and treatments of insomnia
• Differentiate between the parasomnias
• Describe treatments for different types of parasomnias
• Describe how psychoactive substances affect consciousness
• Differentiate between hypnosis, meditation, and trance
• Discuss the use of altered states of consciousness in different world cultures