The Big Picture: Chapter Overview
During much of the 20th century, consciousness was not considered for study in psychology and the focus of the science was mainly on observable behaviors. Consciousness is awareness of both internal and external stimuli or events, including the self and thoughts about personal experiences. Awareness occurs at various levels: higher-level consciousness (the most alert state), lower-level consciousness (automatic processing and daydreaming), altered states of consciousness (e.g., drug induced, hypnosis, fatigue), subconscious awareness (subconscious creativity, sleep, and dreams), and no awareness (unconsciousness). Current neuroscience theories about consciousness argue that rather than having specific parts of the brain associated with consciousness, it seems that different parts and systems of the brain work together simultaneously to produce consciousness.
We dedicate more time to sleeping than to any other activity in our life span; approximately one-third of our lives is spent sleeping. Biological rhythms, such as the circadian rhythm, influence the daily patterns of sleeping and awake time. The daily rhythm is synchronized by our nervous system based on information such as daylight. We need sleep because it helps us restore, adapt, grow, and enhance memory, all positive effects that contribute to adaptation to the challenges of the environment. Sleep deprivation has been associated with many negative effects among which are hallucinations, speech and movement problems, decreased brain activity, decreased alertness, impaired decision-making, and ineffective communication skills. Developmental stages have been associated with differences in sleeping patterns. In late adolescents (16-18 years old) the biological clock automatically changes and delays the time of sleepiness to approximately one hour later than it is for younger adolescents. Later in life, during middle age, the biological clock moves sleepiness back to an earlier time. The sleep stages correspond to electrophysiological changes that can be measured using the EEG, a measure of the brain's electrical activity. When a person is awake, the EEG shows beta waves, which are high in frequency and low in amplitude. During relaxed or drowsy state, the EEG pattern is alpha waves, which are more synchronous than beta waves. When we sleep, we pass through four stages, from light sleep in stage 1 to deep sleep in stages 3 and 4. Sleep stages form a type of cycle, in which we go from stage 1 thru 4 (non-REM sleep) and proceeds to a more wakeful state; however, instead of going back to stage 1, we go into a stage characterized by rapid eye movement, thus referred to as REM sleep. Most dreaming occurs in REM sleep. We complete several sleep cycles nightly. The amount of REM sleep changes over the life span, raising questions about the purpose of REM sleep. During REM sleep, the brain carries out complex processes. Sleep disorders include insomnia, sleepwalking, sleeptalking, nightmares and night terrors, narcolepsy, and sleep apnea.
Dreams have long been of interest and several theories have been proposed to explain them. According to Freud's view, dreams reflect wish fulfillment of unmet needs and have manifest content and latent content. The cognitive view holds that dreams are related to information processing, memory, and problem solving. According to the activation-synthesis view, dreams are the brain's way of making sense out of neural activity while we are sleeping.
Hypnosis is a psychological state of altered attention in which the individual is very receptive to suggestion. In the eighteenth century, Mesmer credited his success in curing his patients' problems to animal magnetism, but what was really occurring was a form of hypnotic suggestion. Hypnosis involves four steps: (1) minimization of distractions and comfort, (2) person is asked to concentrate on something specific, (3) expectations about the hypnotic state are shared with the person, and (4) suggestions begin with predictions of events that can be expected, such as "your eyes are getting tired," followed by suggestions that are then easily accepted by the person. That hypnosis is truly an altered state of consciousness has been challenged by the social cognitive behavior view of hypnosis, which argues that hypnotized people are basically acting as they believe hypnotized people act. Hypnosis is used in psychotherapy, medicine, and other areas in which having a person reach this level of relaxation and openness to suggestion could be of benefit for the person.
Psychoactive drugs are drugs that alter consciousness. Users of psychoactive drugs may develop tolerance, physical dependence, or psychological dependence. The three main types of psychoactive drugs are depressants, stimulants, and hallucinogens. Alcohol is an extremely powerful drug and is a depressant. Alcoholism, a disorder that involves long-term uncontrollable excessive use of alcohol, is influenced by both genetics and environmental factors. Barbiturates (e.g., sleeping pills), tranquilizers (e.g., Valium), and opiates (e.g., morphine, heroin) are other depressants that are abused. Stimulants are drugs that increase activity in the central nervous system. A group of widely prescribed stimulants is amphetamines. Cocaine is also classified as a stimulant and is associated with a rush of euphoria; crack is an intensified form of cocaine and is usually smoked. MDMA (Ecstasy) is an illegal synthetic drug that has both stimulant and hallucinogenic effects and causes brain damage. Two stimulants that are widely used are caffeine and nicotine. Hallucinogens are drugs that modify an individual's perceptual experiences. LSD and marijuana, which produces its effect by disrupting neurons and neurotransmitters, are examples of hallucinogens.
Addiction is characterized by an overwhelming involvement with using a drug and securing its supply. The disease model of addiction describes addiction as a lifelong disease characterized by loss of control and a requirement of treatment for recovery. Critics of this view see addiction as a habit and a source of gratification, not as a disease.