Understanding Consciousness: Circadian Rhythm, Sleep Stages, Dreams, and Substances - Prof, Study notes of Psychology

Download Understanding Consciousness: Circadian Rhythm, Sleep Stages, Dreams, and Substances - Prof and more Study notes Psychology in PDF only on Docsity! 1 Consciousness and Its Variations Circadian Rhythm • Any rhythmic change that continues at close to a 24-hour cycle – EX: sleep and wakefulness Electroencephalogram (EEG) • Electrodes placed on the scalp provide a gross record of the electrical activity of the brain • EEG recordings are a rough index of psychological states EEG Waves of Wakefulness • Awake, but non-attentive: large, regular alpha waves 1 second Alpha waves Awake, nonattentive 1 second Beta waves Awake, attentive • Awake and attentive: low amplitude, fast, irregular beta waves Stages of Sleep • Sleep stage 1: brief transition stage when first falling asleep • Stages 2 through 4 (slow-wave sleep): successively deeper stages of sleep • Characterized by an increasing percentage of slow, irregular, high-amplitude delta waves Delta waves Sleep stage 1 1 second Sleep stage 4 Sleep stage 2 Spindlers (bursts of activity) 2 Stages of Sleep • Sleep stages progress 1-2-3-4-3-2-1-REM • The whole cycle takes about 90 minutes, then repeats • REM sleep is characterized by EEG patterns that resemble beta waves of alert wakefulness – muscles most relaxed, sleep paralysis – rapid eye movements occur – dreams occur • Four or five sleep cycles occur in a typical night’s sleep; as the person repeats the sleep cycle, less time is spent in slow-wave, more is spent in REM Functions of Sleep • Restoration theory—body wears out during the day and sleep is necessary to put it back in shape • Adaptive theory—sleep emerged in evolution to preserve energy and protect during the time of day when there is little value and considerable danger Sleep Deprivation • Has little effect on performance of tasks requiring physical skill or intellectual judgment • Hurts performance on simple, boring tasks more than challenging ones • Most reliable effect is sleepiness itself Individual Differences in Sleep Drive • Some individuals need more and some less than the typical 8 hours per night • Nonsomniacs—sleep far less than most, but do not feel tired during the day • Insomniacs—have a normal desire for sleep, but are unable to sleep and feel tired during the day Sleep Disorders • Insomnia—inability to fall asleep or stay asleep • Night terrors—sudden and intense fear accompanied by physiological reactions (e.g., rapid heart rate, perspiration) that occur during slow-wave sleep (usually stage 3 or 4). • Somnambulism—sleep walking • Sleep apnea—failure to breathe when asleep Dreams and REM Sleep •Dreams—vivid, detailed dreams consisting of sensory and motor sensations experienced during REM •Nightmares •Lucid dreaming