4.10 CHAPTER REVIEW

KEY POINTS

• Consciousness refers to your immediate awareness of mental activity, internal sensations, and external stimuli. Most psychologists today consider consciousness an important area of research, as did early psychologists.

• Circadian rhythms are regulated by the suprachiasmatic nucleus (SCN), the “master clock” located in the hypothalamus of the brain. In response to light detected by special photoreceptors, the SCN reduces the production of melatonin by the pineal gland. Increased melatonin makes you sleepy.

• In the absence of environmental time cues like sunlight, human circadian rhythms drift toward a 24.2-hour day. Circadian rhythms become disrupted when environmental time cues are out of sync with the body clock. Symptoms of jet lag can be produced by travel across time zones or by rotating shift work.

• The invention of the electroencephalograph, which produces an EEG or electroencephalogram, and the discovery of rapid eye movements (REM) changed scientific views about sleep. The two basic types of sleep are REM sleep and NREM sleep.

• When we are awake and alert, the brain generates beta brain waves. As brain activity gears down and drowsiness sets in, alpha brain waves are generated. Hypnagogic hallucinations can occur during this drowsy, presleep phase.

• Each sleep stage is characterized by a specific pattern of brain activity. In the first 90 minutes of sleep, four different stages of NREM sleep are followed by a brief episode of REM sleep. Stage 2 of sleep is defined by the appearance of sleep spindles and K complexes. Throughout the night, episodes of REM sleep become progressively longer and NREM episodes become shorter.

• As people age, periods of REM sleep and deep sleep become shorter, and more sleep time is spent in stage 2 NREM.

• Sleep is important in maintaining immune function, learning and memory, mood regulation, and other physiological processes. Sleep patterns vary among species and may be the result of evolutionary adaptation. Sleep deprivation studies and the phenomenon of REM rebound demonstrate the biological need to sleep.

• Sleep thinking occurs during NREM sleep. A dream is a story-like, unfolding episode of mental images that typically occurs during REM sleep but can also occur during NREM.

• During REM sleep, the brain is cut off from external stimuli. The frontal lobes and primary visual cortex are inactivated, but the hippocampus, amygdala, and other visual centers are highly active.

• Most dreams reflect everyday concerns and include familiar people and settings. Changes in brain chemistry and functioning that occur during sleep probably contribute to the inability to remember dreams. There are individual differences in dream recall. Nightmares are unpleasant anxiety dreams.

• Sigmund Freud believed that dream images are symbols of unconscious wishes. According to Freud, dreams are composed of manifest content and latent content. The activation-synthesis model of dreaming proposes that dreams reflect our subjective awareness of brain activation during sleep. According to the neurocognitive model of dreaming, dreaming cognition is similar to waking cognition.

• Sleep disorders are serious disturbances in the normal sleep pattern that interfere with daytime functioning and cause subjective distress.

• Dyssomnias, such as insomnia and obstructive sleep apnea (OSA), involve interruptions in the amount, quality, or timing of sleep. The symptoms of narcolepsy, including cataplexy, are experienced during the day. Narcolepsy may be associated with low levels of hypocretins. Parasomnias involve undesirable physical arousal, behavior, or events during sleep or sleep transitions; examples include sleepwalking, sleep terrors, sleep-related eating disorders, and sleepsex.

• Hypnosis is an unusual state of awareness, defined as a cooperative social interaction in which the hypnotic participant responds to suggestions made by the hypnotist. Changes in perception, memory, and behavior may be produced. People vary in hypnotic susceptibility.

• Under hypnosis, profound sensory and perceptual changes may be experienced, including pain reduction and hallucinations. Posthypnotic suggestions influence behavior outside the hypnotic state. Hypnosis is used in habit control, but its effectiveness varies. Hypnosis can produce posthypnotic amnesia. Although hypnosis does not increase the accuracy of memories, it does increase confidence in memories and can produce false memories. Hypnosis cannot be used to make people perform behaviors that are contrary to their morals or values.

• The neodissociation theory of Ernest Hilgard explains hypnosis as involving dissociation and a hidden observer. Some psychologists believe that hypnosis is not a special state of consciousness but can be explained by social and cognitive processes.

• Meditation techniques induce a state of focused attention and heightened awareness. Two forms of meditation are focused awareness and open monitoring.

• Early research on meditation emphasized stress relief and relaxation. Research today studies meditation’s effects on the brain and basic psychological processes, including attention, memory, cognition, and emotion. Meditation techniques are also used in psychotherapy.

• Psychoactive drugs can alter arousal, mood, thinking, sensation, and perception. Many psychoactive drugs are addictive, producing physical dependence and drug tolerance. The physically dependent person who stops taking a drug experiences withdrawal symptoms, which often include the drug rebound effect.

• Psychoactive drugs affect brain activity by influencing synaptic transmission. Drug effects can be influenced by the person’s weight, gender, race, metabolic rate, and the presence of other drugs. Personality characteristics, mood, expectations, experience with the drug, and the setting in which the drug is taken also affect the drug response.

• Drug abuse (formally called substance use disorder) refers to recurrent substance use that involves impaired control, disruption of social, occupational, and interpersonal functioning, and the development of craving, tolerance, and withdrawal symptoms.

• Depressants are physically addictive drugs that inhibit central nervous system activity. Depressants include alcohol, barbiturates, inhalants, and tranquilizers. Psychologically, alcohol lessens inhibitions, but its effects vary, depending on the person’s environment and expectations. Barbiturates and inhalants produce relaxation and reduce inhibitions.

• Opioids are addictive drugs, chemically similar to morphine, that relieve pain and produce feelings of euphoria. The opiates include opium, morphine, codeine, heroin, methadone, and prescription painkillers. Opioids relieve pain by mimicking the effect of endorphins in the brain.

• Stimulants include caffeine, nicotine, amphetamines, and cocaine. The stimulants increase brain activity, and all stimulants are addictive. Prolonged use of amphetamines or cocaine can lead to stimulant-induced psychosis.

• Psychedelic drugs include mescaline, LSD, and marijuana. The psychedelics create perceptual distortions, alter mood, and affect thinking. Although psychedelic drugs are not physically addictive, they can cause a variety of harmful effects.

• The “club drugs” are synthetic drugs used at dance clubs, parties, and “raves.” These drugs include MDMA (ecstasy) and the dissociative anesthetics PCP and ketamine.

KEY TERMS

KEY PEOPLE