Sleep and Dreams. Sleep and Dreams. Brain Waves and Sleep Stages Typical Nightly Sleep Stages. Chapter 7 States of Consciousness

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1 Chapter 7 States of Consciousness States of Consciousness Consciousness our awareness of ourselves and our environments Fantasy Prone Personality imagines and recalls experiences with lifelike vividness spends considerable time fantasizing Sleep and Dreams Biological Rhythms periodic physiological fluctuations Circadian Rhythm the biological clock regular bodily rhythms that occur on a 24 hour cycle wakefulness body temperature Sleep and Dreams REM (Rapid Eye Movement) Sleep recurring sleep stage vivid dreams paradoxical sleep muscles are generally relaxed, but other body systems are active Sleep periodic, natural, reversible loss of consciousness Brain Waves and Sleep Stages Typical Nightly Sleep Stages Alpha Waves slow waves of a relaxed, awake brain Delta Waves large, slow waves of deep sleep Hallucinations false sensory experiences Sleep stages Awake REM Hours of sleep 1

2 Sleep Deprivation Effects of Sleep Loss fatigue impaired concentration immune suppression irritability slowed performance accidents planes autos and trucks Sleep Disorders Insomnia persistent problems in falling or staying asleep Narcolepsy uncontrollable sleep attacks Sleep Apnea cessation of breathing often associated with snoring repeatedly awakes sufferer Night Terrors and Nightmares Night Terrors occur within 2 or 3 hours of falling asleep, usually during Stage 4 high arousal- appearance of being terrified Nightmares occur towards morning during REM sleep Sleep Walking walking or carrying our behaviors while asleep Dreams Mental activity that takes place during sleep 8 out of 10 dreams involve negative emotions Incorporate everyday events Do not occur in a split second correspond to a realistic time scale Sleep Talking Dreams- Freud Sigmund Freud- The Interpretation of Dreams (1900) wish fulfillment discharge otherwise unacceptable feelings Manifest Content remembered story line Latent Content underlying, uncensored meaning Why Dream? As Information Processing helps consolidate day s memories stimulates neural development As Physiological Function Provide sleeping brain periodic stimulation 2

3 Drugs and Consciousness Psychoactive Drug a chemical substance that alters perceptions and alters mood Physical Dependence physiological need for a drug marked by unpleasant withdrawal symptoms Psychological Dependence a psychological need to use a drug for example, to relieve negative emotions Dependence Tolerance need for progressively larger doses to achieve same effect Withdrawal discomfort and distress with discontinued use Psychoactive Drugs Psychoactive Drugs Depressants drugs that reduce neural activity slow body function alcohol, barbiturates, opiates Stimulants drugs that excite neural activity speed up body function caffeine, nicotine, amphetamines Hallucinogens psychedelic (mind-manifesting) drugs that distort perceptions and evoke sensory images in the absence of sensory input LSD Psychoactive Drugs Near Death Experiences Drug Type Pleasurable Effects Adverse Effects Alcohol Depressant Initial high followed by Depression, memory loss, organ relaxation and disinhibition damage, impaired reactions Heroin Depressant Rush of euphoria, relief from Depressed physiology, pain agonizing withdrawal Caffeine Stimulant Increased alertness and Anxiety, restlessness, and wakefulness insomnia in high doses; uncomfortable withdrawal Metham- Stimulant Euphoria, alertness, energy Irritability, insomnia, phetamine hypertension, seizures Cocaine Stimulant Rush of euphoria, confidence, Cardiovascular stress, energy suspiciousness, depressive crash Nicotine Stimulant Arousal and relaxation, sense Heart disease, cancer (from tars) of well-being Marijuana Mild Enhanced sensation, pain relief Lowered sex hormones, disrupted hallucinogen distortion of time, relaxation memory, lung damage from smoke Near Death Experience an altered state of consciousness reported after a close brush with death often similar to drug-induced hallucinations 3

4 SENSATION AND PERCEPTION Sensation and Perception Sensation: Receiving Messages About the World Sense organs See, hear, taste, smell, touch, balance, and experience the world Sensory receptor cells transmit sensation Perception interpreting information and forming images Stimulus Sensation and Perception Sensory Limits: How Strong Must Messages Be? Threshold lower limits Absolute threshold smallest to be detected 50% of time Difference threshold smallest difference between 2 stimuli to be detected 50% of time Sensory adaptation one s sensitivity to a stimulus varies from time to time Fatigue, inattention, repeated exposure Sensory Thresholds A candle flame seen at 30 Vision mi. on a clear, dark night Hearing Taste Smell Touch The tick of a watch under quiet conditions at 20 ft. One teaspoon of sugar in 2 gallons of water 1 drop of perfume diffused into the entire volume of a 3 room apartment The wing of a bee falling on your cheek from a height of 1 cm Color Blindness Kinesthesis This is the sense of bodily movements. Its receptors are nerve endings found in muscles, tendons, and linings of joints. Equilibrium This is also called as the Static Sense. Two kinds of receptors give information about movements of the head and permit a sense of balance of the body. Semicircular canals and the Vestibular canal. Both are located in the inner ear next to cochlea. 1

5 PERCEPTION The organization of sensory input into meaningful experiences. Meaning? The brain receives information from the senses and organizes and interprets it into meaningful experiences. Gestalt The experience that comes from organizing bits and pieces of information into meaningful wholes ORGANIZATION IN PERCEPTION Figure and ground when we perceive an object, usually one part tends to stand out while the rest seems to remain in the background. The part which stands out is called the figure and the rest of the stimulus pattern is called the ground. Figure and Ground Grouping we are concerned more with the figure than with the ground. *The principles of similarity stimuli which are similar tend to be perceived as forming a group. 2

6 Similarity *The principle of proximity there is a tendency to perceive stimuli which are near one another as belonging together. *The principle of closure when fragmentary stimuli form enough of a familiar figure, we tend to perceive the whole figure, ignoring the missing part of parts. *The principles of continuity stimuli which from a continuous pattern are perceived as a whole, the pattern they make generally appears as a figure apart from the ground. ATTENTION AND PERCEPTION Perception is selective. The direction of perception toward selected objects is called attention. A number of stimulus conditions help determine the direction of attention DEPTH PERCEPTION This is the ability to see threedimensional space and accurately judge distances. A study of perception would be incomplete without considering perceiving the third dimension- distance and depth. 3

7 Perception - Depth Perception ERRORS IN PERCEPTION Illusion a perception which is common but usually considered mistaken. This is an error which dependsd on stimulus conditions and occur in normal individuals. Hallucinations are false perceptions that occur under abnormal conditions. 1.Illusions based on relative size. 2. Illusions based on intersecting lines. 3. Ponzo illusion. 4