Why It Matters: States of Consciousness

A painting shows two children sleeping.

Figure 1. Sleep, which we all experience, is a quiet and mysterious pause in our daily lives. Two sleeping children are depicted in this 1895 oil painting titled Zwei schlafende Mädchen auf der Ofenbank, which translates as “two sleeping girls on the stove,” by Swiss painter Albert Anker.

Our lives involve regular, dramatic changes in the degree to which we are aware of our surroundings and our internal states. While awake, we feel alert and aware of the many important things going on around us. Our experiences change dramatically while we are in deep sleep and once again when we are dreaming. Sometimes, we seek to alter our awareness and experience by using psychoactive drugs; that is, drugs that alter the central nervous system and produce a change of consciousness or a deep meditative state. Consciousness is an awareness of external and internal stimuli. As discussed in the module on the biology of psychology, the brain activity during different phases of consciousness produces characteristic brain waves, which can be observed by electroencephalography (EEG) and other types of analysis.

This module will discuss states of consciousness with a particular emphasis on sleep. You’ll learn about the different stages of sleep, sleep disorders as well as the altered states of consciousness produced by psychoactive drugs, hypnosis, and meditation.