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Psychology, 5/e Wortman, Loftus & Weaver | |||||
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Psychology, 5/e Wortman, Loftus & Weaver | |||||
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By studying the various abnormal states of consciousness, psychologists can gain deep insights into its broader and more conventional aspects (Theme 2). Generally, consciousness is defined as the awareness of the thoughts, images, sensations, and emotions that flow through one’s mind. William 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.
Circadian rhythms describes the daily cycles of physiological changes. The sleep-wake cycle is part of these rhythms.
There are two main theories about why we sleep. The recuperative theory states that sleep is a time for the body to repair and recover from the day’s activities. The circadian theory argues that organisms sleep at certain times because they are best adapted to sleep at one time and carry out activities during another.
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 participants to an electroencephalograph (EEG) 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 sleep becomes deeper, delta waves (1/2-2 cycles per second) become predominant, occupying 50% 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. The activation-synthesis hypothesis states that the often strange quality of dreams is caused by the brain trying to make sense of random, meaningless neural activity.
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.
Many sleep-inducing drugs inhibit REM sleep, as does alcohol. If participants are deprived of REM sleep, they will spend more time in REM sleep on the following night—the REM rebound. Researchers are not sure why we need REM sleep.
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). Rosalind Cartwright has studied the possibility of controlling dreams by conscious thought. Part of her studies have included trying to help participants resolve personal conflicts in their dreams.
The most common sleep disorder is insomnia, the inability to stay asleep or difficulty going to sleep. It affects as much as 20% 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.
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. Many people believe that drugs "know" which symptom the sufferer is hoping to relieve and that drugs can act on just that symptom. This is called the magic bullet myth.
Stimulants produce physiological and mental arousal and include drugs as mild as caffeine and nicotine or as powerful as cocaine and amphetamines. Caffeine, which is the most frequently used drug in the world, increases heart and respiration rates and raises blood pressure, enhancing alertness. Nicotine is another stimulant. It acts as an appetite suppressant, and, like caffeine, is addictive. Because nicotine is toxic, smoking causes cancer and is responsible for nearly half a million deaths per year.
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.
The effects of cocaine and amphetamines seem to result from activation of the reticular formation and regions of the forebrain. These drugs 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 with in seconds of being smoked. Crack is extremely addictive.
Alcohol is the most widely used psychoactive drug in the United States. Alcohol is a central nervous system depressant, which is a drug that suppresses nerve impulses and tends to reduce anxiety. 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%will relax inhibitions; levels of .3% to .4% may cause coma, and levels exceeding .5% 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 decreased 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% 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. Fetal alcohol syndrome afflicts children whose mothers drink excessively during pregnancy. Such children often suffer from mental retardation, deficient growth, and defects in the skull, face, and brain.
Opiates such as heroin, morphine, opium, and codeine are all derived from the poppy plant. Opiates are powerful painkillers, sometimes producing euphoria and drowsiness, and tend to be extremely addictive. Benzodiazepines, such as Valium and Xanax, are used to reduce anxiety, and can be somewhat addictive. Benzodiazepines also act as sleep aids. Like benzodiazepines, barbituates also induce sleep, but are more addictive and can be lethal at high doses. Mixing barbituates with alcohol is extremely dangerous.
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, because these characteristics often precede use, the long-term effects of marijuana use are difficult to specify.
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.
Through meditation, some individuals who practice yoga 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 participant 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 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 that 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 hidden observer phenomenon attempts to explain the paradox that hypnotized persons sometimes report feeling pain without showing signs of discomfort. Here, hypnotized participants experience a part of consciousness that remains hidden from another part of consciousness, the hypnotized self.
Hypnosis is difficult to define, and at present no clear explanation for the phenomenon exists. Most people (about 95%) 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 has been used to treat pain caused from battle injuries, severe burns, and childbirth. Although hypnosis has been used to help people break habits such as smoking, hypnosis alone has not proven to be an effective long-term treatment.
Great controversy exists over whether hypnosis can be used to recall psychologically threatening memories. Recent research has not supported the claim that hypnosis can do this. However, hypnosis does tend to increase the confidence with which hypnotized individuals report their supposed memories. These findings cast great doubt upon whether hypnosis can be used effectively in psychotherapy or in solving crimes that happened in the distant past.
Psychologists are very interested in the concept of dissociation, a separation of different aspects of consciousness and behavior. They believe that some sort of unconscious dissociation occurs in everyone (Theme 3). A great deal of knowledge about the human mind has been gained from studying dissociation (Theme 2). By studying dissociation, psychologists have learned that 1) some types of awareness might not require awareness to function, 2) that certain blind individuals have been able to exhibit behavior which suggests that they can see, a concept called blindsight, and 3) that the behavior of substance abusers and addicts may be influenced by the presence of certain drugs, even without the abusers’ awareness.
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