CONCEPT I: Cyclical States of Consciousness

Generally, consciousness is defined as the awareness of the thoughts, images, sensations, and emotions that flow through one's mind. James described consciousness as a perpetually flowing stream. Early behaviorists thought the study of consciousness had no place in psychology since it could not be measured objectively. Most modern psychologists disagree, and instead believe it is one of the most important aspects of human experience.

Consciousness is related to brain activity in an interactive way, each influencing the other. Consciousness also has many modes, but all are characterized by distinctive awareness of perceptions, thoughts, and feelings.

Circadian rhythms describes the daily cycles of physiological changes. The sleep-wake cycle is part of these rhythms. Studies show that sleep is accompanied by elevated levels of certain neurotransmitters or other chemicals, but it is not clear that these chemicals cause sleep. The mechanism that brings on sleep remains unknown, but it is thought that sleep is controlled by specific neural circuits associated with the reticular formation.

Sleep research is usually conducted by connecting subjects to an EEG (electroencephalograph) and recording their brain waves as they drift into sleep. Different types of brain waves are typically recorded at different stages of sleep. Beta waves (14+ cycles per second) are fastest and are typical in a fully awake person. Alpha waves (8-12 cycles per second) are characteristic of relaxation. As a person falls asleep, theta waves (3-7 cycles per second) also become evident. As sleep becomes deeper, delta waves (1/2-2 cycles per second) become predominant, occupying 50 percent of the EEG in sleep's deepest stages. Delta sleep increases when a person is sleep-deprived or exhausted, and it has been associated with restoration of the skeletal muscles or the sensory system involved in controlling them. Although delta sleep is characterized by deep relaxation, this is the stage during which most episodes of sleepwalking, sleeptalking, and intense nightmares occur.

In a typical night's sleep, you progress from lighter sleep to deeper sleep and back about every 90 minutes. In these lighter stages, you are likely to enter REM (rapid eye movement) sleep, the stage of sleep associated with dreaming. You dream about four or five times each night. REM sleep differs greatly from non-REM sleep. The scanning hypothesis speculates that the eye movements in REM are due to the dreamer's "watching" the dream's activity. Most researchers, however, suspect that dreaming does not cause rapid eye movements, but rather both dreaming and REM are produced by the increased activity of the brain during this stage.

REM sleep is paradoxical in that it appears to be both a lighter stage of sleep (as indicated by EEGs and physiological measures) and a deeper stage of sleep (as evidenced by lack of muscle tone). The pons seems to be involved both in activating the brain and in inhibiting muscle movements in REM sleep.

If subjects are deprived of REM sleep, they will spend more time in REM sleep on the following night—the REM rebound. Several hypotheses have been proposed to explain the possible value of REM sleep. Perhaps it is the time the brain adapts to disturbing life events. Perhaps REM sleep plays a role in consolidating information into long-term memory, a hypothesis supported by the finding that people need less REM sleep as they grow older (newborns spend about 50 percent of their sleep in REM; old people, less than 5 percent). Finally, REM sleep may provide a means of reducing built-up energy when our biological needs go unmet. People who need little sleep have less REM sleep as well, and also tend to be energetic and aggressive. Some research suggests that REM-sleep deprivation may be an effective treatment for patients who are severely depressed, chronically tired, or apathetic.

By age 70, an average person will have had 150,000 dreams, most of which are dull and quickly forgotten.

Sigmund Freud believed that dreams have two levels of meaning: the manifest content is the story the dreamer remembers; the latent content is the deeper, underlying meaning of the dream, which can be analyzed to reveal unconscious psychosexual conflicts. Most psychologists (including the psychoanalyst Alfred Adler) who use dream analysis favor interpretation of the dream's direct meaning (manifest content). Some psychologists are working to develop "dream management" techniques, which will allow subjects to control their dreams. Stephen La Berge, for instance, has tried to increase his lucid dreams—dreams in which he realizes he is dreaming—as a means of reducing nighttime conflicts.

The most common sleep disorder is insomnia, the inability to stay asleep or difficulty going to sleep. It affects as many as 20 percent of all people at some time in their lives, and is usually caused by stress. Sleep apnea is the stoppage of breathing after falling asleep, which may then be followed by awakening and gasping for air. Narcolepsy is a disorder in which wide-awake people suddenly fall asleep, losing muscle control and often entering the REM period immediately.

A daydream is a train of thought that departs from the person's immediate situation and that causes a loss of touch with the outside world. Most people experience daydreams about every 90 to 100 minutes, a pattern similar to REM sleep. It is possible the same mechanism may underlie both processes.

CONCEPT II: Induced States of Consciousness

Drugs are substances that can alter the functioning of a biological system. Psychoactive drugs interact with the central nervous system and alter mood, perception, thinking, and behavior.

Alcohol is the most widely used psychoactive drug in the United States. Alcohol is a central nervous system depressant and suppresses nerve impulses. People sometimes feel elated when they drink a small amount of alcohol because it slows down the brain centers that normally control social inhibitions. With increased doses, other central nervous system functions deteriorate. Blood alcohol levels of .05 percent will relax inhibitions; levels of .3 percent to .4 percent may cause coma, and levels exceeding .5 percent cause death.

Expectations concerning the effects of alcohol play a significant role in altering behavior. Individuals given nonalcoholic drinks, but told they were consuming alcohol, behaved with less social inhibition.

Alcohol consumption affects the transfer of information from short-term to long-term memory. Alcoholic blackout is the loss of memory for events that occurred while drinking. About 10 percent of those seeking help for alcoholism have suffered chronic brain damage. Korsakoff's syndrome, a severe form of damage, results in virtually no memory for events occurring since the disorder's onset. Those who indulge in drinking binges run a greater risk of damaging their health than those who regularly drink in moderation.

Stimulants produce physiological and mental arousal and include drugs as mild as caffeine and nicotine or as powerful as cocaine and amphetamines. The effects of cocaine and amphetamines seem to result from activation of the reticular formation and regions of the forebrain. They also enhance the activities of norepinephrine and dopamine.

Cocaine, once an ingredient in Coca-Cola, is today illegal, although it is becoming increasingly popular in middle-class America. It can be "snorted," smoked, or injected. It produces euphoria. Users report that it elevates mood and improves performance, although users overestimate their abilities. Since energy is expended without replenishing the source, when the drug effects wear off the user "crashes" with exhaustion. Chronic heavy use damages the mucous membranes and can generally poison the system. Large doses can cause mental deterioration, agitation, paranoia, and hallucinations. One especially horrifying hallucination is the sensation of bugs crawling under one's skin. A new form, called crack, is exceptionally powerful, producing a rush within seconds of being smoked.

The amphetamines, such as Dexadrine and Benzedrine, were once prescribed to help people stay awake or lose weight. Under their influence, people feel wonderful and powerful, even though their competence does not actually increase. Extended use of amphetamines leads to tolerance, with increasingly larger doses needed to produce the same euphoria. Overuse can lead to paranoia, meaningless wandering of thought, and periods of sometimes serious depression when the drug wears off. Heavy users show symptoms similar to those of schizophrenia. These symptoms are believed to involve the dopamine pathways in the brain. Amphetamine abuse can cause brain damage.

Hallucinogens, or drugs that are capable of producing hallucinations, have been extracted from plants and used since earliest human history. Marijuana and hashish are often called minor hallucinogens because of the mildness of their effects compared to the major hallucinogens, which include mescaline, LSD, and PCP.

LSD (lysergic acid diethylamide) is much stronger than natural hallucinogens such as psilocybin and mescaline. LSD blocks the effects of serotonin (a neurotransmitter), but other drugs block serotonin without similar effect. LSD produces a series of dramatic hallucinations and feelings of increased awareness and knowledge. In fact, LSD impairs thinking ability as measured by performance on simple tasks. Panic reactions sometimes occur.

PCP (phencyclidine), also called angel dust, is another powerful hallucinogen. It tends to produce depersonalization, mental confusion, insomnia, delusions and hallucinations, and the urge to act violently. PCP molecules bind to receptor sites in the limbic system, but researchers do not yet understand exactly how the drug works.

Although use of marijuana is a fairly recent development in the United States, it has been used as an intoxicant in other cultures for centuries. About 50 million Americans have used marijuana; 10 to 15 million are regular users. Cannabis sativa, a common weed, is dried to produce marijuana. Hashish is made from the flowers of the cannabis plant. Both contain THC (tetrahydrocannabinol) as their active ingredient and can be smoked or eaten. Although the effects of marijuana vary from person to person, they typically include heightened sensory experiences, elation, an enhanced sense of meaning, and time distortion. Drug experiences with marijuana can be pleasant or unpleasant.

Marijuana elevates mood, often heightening moods and feelings that exist prior to taking the drug. A decrease in the ability to direct thoughts may also occur. Studies indicate that marijuana, like alcohol, impairs transfer of learning from short-term to long-term memory. It seems to reduce the release of acetylcholine in the limbic system, most likely in the hippocampus. Marijuana users generally do more poorly in school than nonusers, but, since these characteristics often precede use, the long-term effects of marijuana use are difficult to specify.

Research on the relationship between drug usage and creativity is inconclusive. Although users often feel more creative, drugs usually produce a diminished capacity for logical thought and for self-criticism.

Through meditation, yogis are able to achieve the state called samadhi, in which awareness is separated from the senses. This and similar experiences in meditation and biofeedback differ from dreaming and hypnosis, since the subject regulates his or her own state of consciousness.

Meditation is a retraining of attention that induces an altered state of consciousness. Some form of meditation has been used in every major religion, although there are large differences in the ways meditation can be practiced. Most forms involve focusing attention on a single stimulus and greatly restricting sensory input. Although the particular physiological changes that result vary depending on the type of meditation, generally they resemble deep relaxation, with lowered metabolic rates and an increase in alpha and theta wave output. Supporters of meditation claim it reduces stress, increases happiness, and enriches life.

Hypnosis is difficult to define, and at present no clear explanation for the phenomenon exists. Most people (about 95 percent) can be hypnotized to some degree if they so desire. Several scales or tests, including the Stanford Scale, have been devised to measure hypnotic susceptibility. People who are highly susceptible to hypnosis tend to have histories of daydreaming, imaginary companions, and absorption in their activities.

Hypnosis is used to reduce the experience of pain, to treat certain behavior problems such as smoking, and to improve memory recall. However, the improvement in memory hypnosis seems to produce is very difficult to demonstrate in controlled laboratory conditions. Reports of improved memory under hypnosis may be due to confabulation or to hypermnesia, the improved recall due to repeated tries; therefore caution should be exercised in using information recalled during hypnosis because it may not be accurate.

Hilgard's dissociation view says that in hypnosis a split occurs in consciousness, allowing certain thoughts, feelings, and behaviors to operate independently of one another. The cognitive role enactment view argues that hypnosis is not an altered state of consciousness, but merely a state of compliance with the hypnotist's suggestions. This role enactment view suggests that the hypnotist's function is to define clearly the role the subject is to play. It further argues that there exists no difference between feats accomplished under hypnosis and what can be accomplished by unhypnotized subjects; thus hypnosis is like any other special state of concentration.

The hidden observer phenomenon has been a focal point in the controversy between the dissociationist view and the role enactment view. Here, hypnotized subjects experience a part of consciousness that remains hidden from another part of consciousness, the hypnotized self. The dissociationists argue that there are two separate parts to the self in these cases, which supports their view of hypnosis as a splitting of consciousness. The role enactment view claims that the hidden observer is yet another role suggested by the hypnotist. Supporting evidence exists for both interpretations, and a full understanding of hypnosis will probably require some sort of combination of both perspectives.