C.4 Chapter 3
CONSCIOUSNESS AND THE TWO-TRACK MIND
Brain States and Consciousness
3-1 What is the place of consciousness in psychology’s history?
Since 1960, under the influence of cognitive psychology, neuroscience, and cognitive neuroscience, our awareness of ourselves and our environment—our consciousness—has reclaimed its place as an important area of research. After initially claiming consciousness as its area of study in the nineteenth century, psychologists had abandoned it in the first half of the twentieth century, turning instead to the study of observable behavior because they believed consciousness was too difficult to study scientifically.
3-2 What is the “dual processing” being revealed by today’s cognitive neuroscience?
Scientists studying the brain mechanisms underlying consciousness and cognition have discovered that the mind processes information on two separate tracks, one operating at an explicit, conscious level (conscious sequential processing) and the other at an implicit, unconscious level (unconscious parallel processing). This dual processing affects our perception, memory, attitudes, and other cognitions.
3-3 How does selective attention direct our perceptions?
We selectively attend to, and process, a very limited portion of incoming information, blocking out much and often shifting the spotlight of our attention from one thing to another. Parallel processing takes care of the routine business, while sequential processing is best for solving new problems that require our attention. Focused intently on one task, we often display inattentional blindness to other events and change blindness to changes around us.
Sleep is the periodic, natural loss of consciousness—as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation. (Adapted from Dement, 1999.)
3-5 How do our biological rhythms influence our daily functioning?
Our bodies have an internal biological clock, roughly synchronized with the 24-hour cycle of night and day. This circadian rhythm appears in our daily patterns of body temperature, arousal, sleeping, and waking. Age and experiences can alter these patterns, resetting our biological clock.
3-6 What is the biological rhythm of our sleeping and dreaming stages?
Younger adults cycle through four distinct sleep stages about every 90 minutes. (The sleep cycle repeats more frequently for older adults.) Leaving the alpha waves of the awake, relaxed stage, we descend into the irregular brain waves of non-REM stage 1 (NREM-1) sleep, often with hallucinations, such as the sensation of falling or floating. NREM-2 sleep (in which we spend the most time) follows, lasting about 20 minutes, with its characteristic sleep spindles. We then enter NREM-3 sleep, lasting about 30 minutes, with large, slow delta waves.
About an hour after falling asleep, we begin periods of REM (rapid eye movement) sleep. Most dreaming occurs in this stage (also known as paradoxical sleep) of internal arousal but outward paralysis. During a normal night’s sleep, NREM-3 sleep shortens and REM and NREM-2 sleep lengthens.
3-7 How do biology and environment interact in our sleep patterns?
Our biology—our circadian rhythm as well as our age and our body’s production of melatonin (influenced by the brain’s suprachiasmatic nucleus)—interacts with cultural expectations and individual behaviors to determine our sleeping and waking patterns.
3-8 What are sleep’s functions?
Sleep may have played a protective role in human evolution by keeping people safe during potentially dangerous periods. Sleep also helps restore and repair damaged neurons. REM and NREM-2 sleep help strengthen neural connections that build enduring memories. Sleep promotes creative problem solving the next day. Finally, during deep sleep, the pituitary gland secretes a growth hormone necessary for muscle development.
3-9 How does sleep loss affect us, and what are the major sleep disorders?
Sleep deprivation causes fatigue and irritability, and it impairs concentration, productivity, and memory consolidation. It can also lead to depression, obesity, joint pain, a suppressed immune system, and slowed performance (with greater vulnerability to accidents).
Sleep disorders include insomnia (recurring wakefulness); narcolepsy (sudden uncontrollable sleepiness or lapsing into REM sleep); sleep apnea (the stopping of breathing while asleep; associated with obesity, especially in men); night terrors (high arousal and the appearance of being terrified; NREM-3 disorder found mainly in children); sleepwalking (NREM-3 disorder also found mainly in children); and sleeptalking.
We usually dream of ordinary events and everyday experiences, most involving some anxiety or misfortune. Fewer than 10 percent of dreams among men (and less among women) have any sexual content. Most dreams occur during REM sleep.
3-11 What functions have theorists proposed for dreams?
There are five major views of the function of dreams. (1) Freud’s wish-fulfillment: Dreams provide a psychic “safety valve,” with manifest content (story line) acting as a censored version of latent content (underlying meaning that gratifies our unconscious wishes). (2) Information-processing: Dreams help us sort out the day’s events and consolidate them in memory. (3) Physiological function: Regular brain stimulation may help develop and preserve neural pathways in the brain. (4) Neural activation: The brain attempts to make sense of neural static by weaving it into a story line. (5) Cognitive development: Dreams reflect the dreamer’s level of development.
Most sleep theorists agree that REM sleep and its associated dreams serve an important function, as shown by the REM rebound that occurs following REM deprivation in humans and other species.
3-12 What are substance use disorders, and what roles do tolerance, withdrawal, and addiction play in these disorders?
Those with a substance use disorder may exhibit impaired control, social disruption, risky behavior, and the physical effects of tolerance and withdrawal. Psychoactive drugs alter perceptions and moods. They may produce tolerance—requiring larger doses to achieve the desired effect—and withdrawal—significant discomfort accompanying attempts to quit. Continued use may lead to addiction, which is the compulsive craving of drugs or certain behaviors (such as gambling) despite known adverse consequences.
3-13 How has the concept of addiction changed?
Psychologists debate whether the concept of addiction has been stretched too far, and whether addictions are really as irresistible as commonly believed. Addictions can be powerful, and many with addictions do benefit from therapy or group support. But viewing addiction as an uncontrollable disease can undermine people’s self-confidence and their belief that they can change. The addiction-as-disease-needing-treatment idea has been extended to a host of excessive, driven behaviors, but labeling a behavior doesn’t explain it. The concept of addiction continues to evolve, as psychiatry’s manual of disorders now includes behavior addictions such as “gambling disorder” and proposes “Internet gaming disorder” for further study.
3-14 What are depressants, and what are their effects?
Depressants, such as alcohol, barbiturates, and the opiates, dampen neural activity and slow body functions. Alcohol tends to disinhibit, increasing the likelihood that we will act on our impulses, whether harmful or helpful. It also impairs judgment, disrupts memory processes by suppressing REM sleep, and reduces self-awareness and self-control. User expectations strongly influence alcohol’s behavioral effects.
3-15 What are stimulants, and what are their effects?
Stimulants—including caffeine, nicotine, cocaine, the amphetamines, methamphetamine, and Ecstasy—excite neural activity and speed up body functions, triggering energy and mood changes. All are highly addictive. Nicotine’s effects make smoking a difficult habit to kick, yet the percentage of Americans who smoke has been dramatically decreasing. Cocaine gives users a fast high, followed within an hour by a crash. Its risks include cardiovascular stress and suspiciousness. Use of methamphetamines may permanently reduce dopamine production. Ecstasy (MDMA) is a combined stimulant and mild hallucinogen that produces euphoria and feelings of intimacy. Its users risk immune system suppression, permanent damage to mood and memory, and (if taken during physical activity) dehydration and escalating body temperatures.
3-16 What are hallucinogens, and what are their effects?
Hallucinogens—such as LSD and marijuana—distort perceptions and evoke hallucinations—sensory images in the absence of sensory input. The user’s mood and expectations influence the effects of LSD, but common experiences are hallucinations and emotions varying from euphoria to panic. Marijuana’s main ingredient, THC, may trigger feelings of disinhibition, euphoria, relaxation, relief from pain, and intense sensitivity to sensory stimuli. It may also increase feelings of depression or anxiety, impair motor coordination and reaction time, disrupt memory formation, and damage lung tissue (because of the inhaled smoke).
3-17 Why do some people become regular users of consciousness-altering drugs?
Some people may be biologically vulnerable to particular drugs, such as alcohol. Psychological factors (such as stress, depression, and hopelessness) and social factors (such as peer pressure) combine to lead many people to experiment with—and sometimes become addicted to—drugs. Cultural and ethnic groups have differing rates of drug use. Each type of influence—biological, psychological, and social-cultural—offers a possible path for drug misuse prevention and treatment programs.