CHAPTER 9
Consciousness
outline
I.ANALYZING CONSCIOUSNESS
Scientists who study consciousness sometimes call their work cognitive science or cognitive neuroscience. Today, three questions dominate the study of consciousness: What is the relationship between the mind and the body? What processes are outside of awareness and how do they affect conscious processes?
A.Some Functions of Consciousness
Consciousness produces the best current interpretation of sensory information in light of past experience and makes this interpretation available to the part of the brain that plans voluntary actions and speech.
B.Levels of Consciousness
Mental activity that you are aware of occurs at the conscious level of experience. However, mental activity can occur outside of consciousness at the nonconscious, or cognitive unconscious, levels. At the nonconscious level, physiological processes that you cannot consciously monitor without the aid of biofeedback occur. The cognitive unconscious includes the preconscious and unconscious levels. The preconscious level contains everything that can easily be brought into consciousness. Other mental activities that can alter thoughts, feelings, and actions but that are more difficult to bring into awareness are said to be in the unconscious.
C.Mental Processing Without Awareness
Research on priming indicates that many important mental operations, such as learning, can occur without awareness.
D.Focus on Research Methods: Subliminal Messages in Rock Music
To investigate whether backward masked messages could be perceived, understood, and influence behavior when music plays forward, researchers recorded readings of the 23rd Psalm and Jabberwocky. The researchers then played them backwards. Participants were unable to discern messages in the backward versions, and no evidence was found to show that backward masked messages could influence behavior. Research should now focus on why the myth of backward masked messages influence on behavior persists.
E.The Neuropsychology of Consciousness
Brain damage can impair consciousness. Documented cases include prosopagnosia and anterograde amnesia.
F.States of Consciousness
State of consciousness refers to the characteristics of consciousness at any particular moment. Possible states range from deep sleep to alert wakefulness, with many gradations in between. Significant changes in behavior and mental processes are characteristic of altered states of consciousness. The value of altered states of consciousness varies from culture to culture.
II.SLEEPING AND DREAMING
Early researchers thought that sleep was a time of mental inactivity. Modern research shows, however, that sleep is actually a very active, complex state.
A.Stages of Sleep
1.Slow-Wave Sleep. Stages 1 through 4 are progressively deeper stages of non-REM sleep. The last two stages—3 and 4—are slow-wave sleep. Each stage has an EEG pattern characterized by slow brain waves and accompanied by deep breathing; calm, regular heartbeat; and reduced blood pressure.
2.REM Sleep. REM (rapid eye movement) sleep, or active sleep, is a paradoxical state in which brain waves and other physiological functions resemble those of a person who is awake, but muscle tone resembles that of paralysis.
3.A Night’s Sleep. Most people travel through the five stages of slow-wave and REM sleep four to six times each night. REM sleep is most frequent during the second half of the night. The amount of time spent in stages 1 to 4 and REM sleep varies with age.
B.Sleep Disorders
1.Insomnia, fatigue resulting from little sleep or difficulty falling asleep, is the most common sleep disorder and is correlated with mental distress. Relaxation training, biofeedback, and sleep restriction therapy are all approaches that can decrease insomnia.
2.People with narcolepsy fall, without warning, into REM sleep from an active waking state.
3.Sleep apnea is a disorder in which people stop breathing momentarily while they sleep. Apnea episodes can occur hundreds of times per night, thus leaving the victim feeling tired during the day.
4.Sudden infant death syndrome (SIDS) is a disorder, affecting primarily infants two to four months old, in which a baby stops breathing and dies. Doctors now recommend that babies sleep on their back to keep them from accidentally suffocating in soft bedding.
5.Nightmares are frightening dreams that can occur during REM sleep. Night terrors occur during stage 4 and are characterized by horrific images, screaming upon wakening, and difficulty in calming down afterward.
6.Sleepwalking, which is most common among children, is walking during non-REM sleep. REM behavior disorder, a condition similar to sleepwalking, occurs during REM sleep. In this condition, the normal paralysis that occurs during REM sleep is absent, and the person acts out his or her dreams.
C.Why Do People Sleep?
1.Sleep as a Circadian Rhythm. Humans have a built-in biological clock that is linked to light and dark environmental cues. Jet lag and its accompanying symptoms of fatigue and irritability are examples of what happens when the sleep-wake cycle is interrupted. Human circadian rhythms are “clocked” in a part of the hypothalamus called the suprachiasmatic nucleus.
2.The Functions of Sleep. Sleep is necessary for resting and restoring the body. REM sleep may help maintain the activity of neurons that use norepinephrine. It may also be a time for developing, checking, and expanding the brain’s nerve connections. Finally, REM sleep may help consolidate what has been learned during the day.
D.Dreams and Dreaming
Dreams are storylike sequences of images, sensations, and perceptions. Lucid dreamers know when they are dreaming. Some theories suggest that dreaming helps mammals process and consolidate information of great personal significance or survival value. Psychodynamic theory suggests that dreams express unconscious wishes. The activation-synthesis theory suggests that dreams represent efforts to make sense of random signals sent to the cortex.
III.HYPNOSIS
Hypnosis is an altered state of consciousness brought on by special techniques and characterized by responsiveness to suggestions for changes in perceptions and behavior.
A.Experiencing Hypnosis
1.Procedures for inducing hypnosis focus people’s attention on a restricted, often monotonous, set of stimuli while asking them to shut out everything else as they imagine certain feelings. Hypnotically susceptible people are more imaginative, have a tendency to fantasize, can focus their attention for long periods, and are able to process information quickly and effortlessly.
2.Under hypnosis, people respond to suggestions and can appear to forget their names or even display age regression. Posthypnotic suggestions affect behavior after hypnosis has ended. Some people experience posthypnotic amnesia, which is an inability to remember what happened under hypnosis. Hypnotized people exhibit reduced planfulness (the ability to initiate action on their own), redistributed attention, increased ability to fantasize, reduced reality testing, and enhanced ability to role play.
B.Explaining Hypnosis
Three major theories attempt to explain hypnosis. According to role theory, subjects under hypnosis merely act in accordance with the hypnotized role. They are not in a special state; they simply comply with the hypnotist’s directions. According to state theory, hypnotized people experience an altered state of consciousness. According to dissociation theory, which is a blend of role and state theories, hypnotized subjects dissociate, or split, various aspects of their behavior and perceptions from the “self” that normally controls these functions. When hypnotized, these subjects are sharing some of this control with the hypnotist.
C.Applications of Hypnosis
Hypnosis has been used to decrease pain from surgery, childbirth, headaches, and cancer. More controversially, it has been used in attempts to enhance memory.
D.Linkages: Meditation, Health, and Stress
Meditation is an altered state of consciousness characterized by inner peace, calmness, and tranquility. Most types of meditation share common characteristics, including a method for focusing, a quiet environment, a comfortable position, a mental device to organize attention, and a passive attitude. Physiological effects include decreases in respiration rate, heart rate, muscle tension, blood pressure, and oxygen consumption, along with the appearance of alpha-wave activity. People who meditate regularly report experiencing decreases in stress-related problems such as anxiety and high blood pressure.
IV.PSYCHOACTIVE DRUGS
Psychoactive drugs cause psychological changes by altering the functioning of the brain. Psychopharmacology is the study of psychoactive drugs.
A.Psychopharmacology
Psychoactive drugs or substances influence the interaction between neurotransmitters and receptors. These drugs get into the brain through the blood supply when they pass the blood-brain barrier. Drugs that act as agonists mimic the effects of neurotransmitters, whereas those acting as antagonists prevent neurotransmitters from binding with receptors and inhibit neurotransmitter activity.
B.The Varying Effects of Drugs
Substance abuse is the self-administration of drugs in ways that deviate from either medical or social norms. Psychological dependence occurs when a person continues to use the drug to gain a sense of well-being even when the drug produces adverse consequences. Physical dependence or addiction exists when there is an altered physiological state in which continued use of the drug is required to prevent the onset of withdrawal syndrome. Tolerance may develop with prolonged use of a drug.
1.Expectations and Drug Effects. People who think they have taken a drug but really have not may display the effects of the drug because they expect to be affected by it. The learned expectations regarding a drug’s effect vary from culture to culture.
C.Depressants
Depressants reduce central nervous system activity. Many depressants increase GABA neurotransmitter activity.
1.Alcohol. Alcohol has an impact on the dopamine, norepinephrine, serotonin, endorphin, and GABA neurotransmitters. Genetics influences people’s tendency toward alcohol dependency.
2.Barbiturates. Also called downers or sleeping pills, barbiturates cause relaxation, some euphoria, and diminished attention, among other effects.
3.GHB. GHB is a naturally occurring substance similar to GABA and has recently become a popular “club drug.”
D.Stimulants
Stimulants increase behavioral and mental activity.
1.Amphetamines. Commonly known as uppers or speed, amphetamines increase the release of and decrease the removal of norepinephrine and dopamine at synapses, resulting in increased receptor activity. Amphetamines stimulate the brain and sympathetic nervous system, raising heart rate and blood pressure and constricting blood vessels. In some extreme cases, abuse of these drugs produces symptoms very similar to paranoid schizophrenia.
2.Cocaine. This drug’s effects are similar to but more rapid than those of amphetamines. Additionally, the effects of cocaine are short-lived, which may help explain why this drug is especially addictive both psychologically and physiologically.
3.Caffeine. This drug decreases drowsiness, makes thought more rapid, increases physical work capacity, and raises urine production. Caffeine can cause physical dependence.
4.Nicotine. This drug stimulates the autonomic nervous system. Regular nicotine use can cause psychological and/or physiological dependence.
5.MDMA. Also called Ecstasy, MDMA is similar to both stimulants and psychedelics. It increases the activity of dopamine neurons. Although MDMA does not appear to be physically addictive, it does cause permanent brain damage and can lead to panic disorder.
E.Opiates
Opiates, which include opium, morphine, heroin, and codeine, cause sleep and pain relief. These drugs are quite addictive and act as agonists for endorphins.
F.Hallucinogens
Hallucinogens, sometimes referred to as psychedelics, cause a loss of contact with reality and induce changes in emotion, perception, and thought.
1.LSD. Lysergic acid diethylamide (LSD) is one of the most powerful psychedelics. LSD is not addictive, but tolerance does develop.
2.Ketamine. Ketamine is used in veterinary medicine, and has hallucinogenic properties when used in humans. Its use can lead to enduring memory impairment.
3.Marijuana. The active ingredient in cannabis sativa is tetrahydrocannabinol (THC).
G.Thinking Critically: Is Marijuana Dangerous?
Some say marijuana usage is dangerous, illegal, and wrong. Others contend that marijuana should be decriminalized and used for medicinal purposes.
What am I being asked to believe or accept?
Marijuana is a dangerous drug. It is addictive, it leads to “hard drug” use, it endangers the user and others, and if used long term, it has adverse effects on health and behavior.
What evidence is available to support the assertion?
Some people become at least psychologically dependent on marijuana. One study indicated a possibility of addiction. Marijuana interacts with the same receptors as heroin, suggesting that it could lead to the use of more addictive drugs. Marijuana disrupts memory formation and motor coordination. One study showed that long-term use impairs intellectual functioning.
Are there alternative ways of interpreting the evidence?
The studies referred to earlier provide inaccurate or incomplete information. The same receptors activated by marijuana and heroin are also activated by sex and chocolate. The correlation between marijuana use and hard drug use could be due to the environment more than to properties of the drug. Studies of long-term effects on memory and reasoning are correlational. There is no evidence of a cause-effect relationship.
What additional evidence would help evaluate the alternatives?
More definitive evidence on marijuana’s short- and long-term effects is needed.
What conclusions are most reasonable?
There is no hard evidence that marijuana is any more harmful than alcohol or tobacco. But though less dangerous than cocaine or heroin, marijuana is not totally harmless, and it is illegal. Scientists must objectively study all of marijuana’s effects—positive and negative.