Presentation on theme: "Variations in Consciousness"— Presentation transcript:
1Variations in Consciousness Chapter 5Variations in Consciousness
2Consciousness: Personal Awareness Awareness of Internal and External StimuliLevels of awarenessJames – stream of consciousnessFreud – unconsciousSleep/dreaming researchConsciousness, or our awareness of internal and external stimuli (including events, internal sensations, thoughts, etc.), is constantly changing. This was recognized by William James in 1902 when he discussed the “stream of consciousness”…an endless flow of ideas.Sigmund Freud was also interested in consciousness, particularly in what was going on just below the surface of the stream. He was one of the first theorists to recognize that consciousness is not an all or none phenomenon…rather there are levels of awareness.Sleep and dreaming researchers also showed that awareness is different during sleep and dreaming, but mental processes occur that are quite similar to waking thought and surprisingly sophisticated.
3The Electroencephalograph: A Physiological Index of Consciousness EEG – monitoring of brain electrical activityBrain-wavesAmplitude (height)Frequency (cycles per second)Beta (13-24 cps)Alpha (8-12 cps)Theta (4-7 cps)Delta (<4 cps)Mental state and cortical activity – correlation issue – F 5.1The electroencephalograph is an instrument used to measure brain electrical activity (brain waves) across large areas of the cerebral cortex. It is basically a physiological index of consciousness.Brain wave activity is divided into four different bands; beta waves, which are correlated with alertness and problem solving; alpha waves, which are correlated with resting and relaxation; theta waves, which are correlated with low alertness and sleep; and delta waves, which are correlated with deep, dreamless sleep.
5Biological Rhythms and Sleep Circadian Rhythms – 24 hr biological cyclesRegulation of sleep/other body functions – F 5.2Physiological pathway of the biological clock:Light levels -> retina -> suprachiasmatic nucleus of hypothalamus -> pineal gland -> secretion of melatoninMelatonin and circadian rhythmsPerformance effects – Recht et al. (1995) study of professional baseball – F 5.3Humans and other animals operate on a 24-hour biological cycle. These daily cycles are particularly important in the regulation of sleep, but also in the regulation of temperature, blood production, hormone production, and other bodily processes.Circadian rhythms vary from person to person, and different people may have different optimal times to fall asleep, have a good night’s sleep, etc.The pathway for regulation of the human biological clock appears to be based in light levels, which go from the eye to an area of the brain called the suprachiasmatic nucleus (in the hypothalamus). This nucleus tells the pineal gland to secrete melatonin, a hormone that adjusts biological clocks.Melatonin supplements are sold in the U.S. as nutritional supplements, but many researchers worry that people are taking too high doses of this substance, when long-term effects have not been tested. Melatonin is a regulated drug in Canada, Great Britain, and many other countries. Research shows that may be helpful in the treatment of jet lag, but timing is very important and hard to get right. Studies also show that melatonin may be useful as a mild sedative, more so in the daytime than at night, when melatonin levels are naturally higher.
6Sleep/Waking Research Instruments:Electroencephalograph – brain electrical activityElectromyograph – muscle activityElectrooculograph – eye movementsOther bodily functions also observedPsychologists who conduct sleep research use the following instruments a great deal: the EEG, which records brain electrical activity; the EMG, which records muscle activity and tension; and the EOG, which records eye movements.They may also record heart rate, breathing rate, temperature, etc., as well as videotape the person sleeping through a window. Believe it or not, people get used to the wires and cameras after only one night.
7Sleep Stages: Cycling Through Sleep Stage 1: brief, transitional (1-7 minutes) – see F 5.4alpha -> thetahypnic jerksStage 2: sleep spindles (10-25 minutes)Stages 3 & 4 : slow-wave sleep (30 minutes)Stage 5: REM, EEG similar to awake, vivid dreaming (initially a few minutes, progressively longer as cycle through the stages)Developmental differences in REM sleep – F 5.6How quickly one falls asleep, how long one sleeps, how one cycles through the various stages – F 5.5Varies from one person to the next – cultural differences – F 5.7Each of us has a signature sleep pattern mostly shaped by biological factors rather than personal habitsSleep researchers have discovered 5 distinctly different stages of sleep, based on physiological recordings.Stage 1 is a brief, transitional stage of light sleep that lasts between 1 and 7 minutes. The EEG moves from predominately alpha waves, when the person is just about to fall asleep, to more theta activity. Hypnic jerks, those brief muscle contractions that occur when one is falling asleep, occur in stage 1 sleep.Stage 2 is characterized by more mixed brain wave activity with brief bursts of higher-frequency brain waves, called sleep spindles.Stages 3 and 4 are characterized by low frequency delta waves.It takes about 30 minutes to reach stage 4, and usually people stay there for about 30 minutes. Then the cycle reverses. When stage 1 should be next in line in the cycle, something interesting happens…rapid eye movement (REM) sleep begins. REM sleep was accidentally discovered by Nathaniel Kleitman in the spring of 1952 – see chapter opening story.REM sleep is characterized by an EEG that looks awake and alert…and by rapidly moving eyes behind the lids, an irregular pulse and breathing rate, and loss of muscle tone. When someone is awakened from REM sleep, they report vivid dreaming.Infants spend much more time in REM than do adults. During adulthood, sleep changes continue with the percentage of slow-wave sleep declining and the percentage of time spent in stage 1 increasing.
10The Neural Bases of Sleep Brain Structures: - F 5.8Ascending reticular activating systemPons, medulla, thalamus, hypothalamus, limbic systemNeurotransmitters:Acetylcholine and serotoninAlso norepinephrine, dopamine, and GABAThe brain structure that is most involved in sleep appears to be the ascending reticular activating system. This is a system of afferent fibers running through the reticular formation that influence physiological arousal. When these fibers are cut, animals will sleep continuously. If they are stimulated, arousal and alertness result.Other brain structures are also involved in sleep, such as the pons (critical in generation of REM sleep), the medulla, thalamus, hypothalamus, and limbic system.The neurotransmitters that appear to be most influential in sleep are acetylcholine and serotonin, although norepinephrine, dopamine, and GABA are also involved in arousal and the course of sleep.Basically, no one center or chemical is at work; sleep is rather an interplay of many neural centers and neurotransmitters.
12Why Do We Sleep? Hypothesis 1: Hypothesis 2: Hypothesis 3: Sleep evolved to conserve organisms’ energyHypothesis 2:Immobilization during sleep is adaptive because it reduces dangerHypothesis 3:Sleep helps animals to restore energy and other bodily resourcesThere are three main hypotheses regarding the evolutionary significance of sleep. To conserve energy, to be immobilized (and therefore out of danger), or to restore energy and other resources used during waking hours.Of the 3, number 3 has the most evidence, but the issue is still hotly debated.
13Sleep Deprivation Complete deprivation 3 or 4 days maxMaximum duration?Partial deprivation or sleep restrictionimpaired attention, reaction time, coordination, and decision makingaccidents: Chernobyl, Exxon Valdez, bus crashes, airline crashesSelective deprivationREM and slow-wave sleep: rebound effect – F 5.9Sleep deprivation studies indicate that people can function surprisingly well when sleep deprived; although effects on mood and performance are present, these are modest. Effects would be more severe, except most people have a hard time going without sleep for more than 3 or 4 days max.Sleep restriction, or partial deprivation, occurs when people make do with less sleep than normal…very common…can cause negative effects, particularly in performance, with long-lasting, difficult, or monotonous tasks...can be very, very costly…Three Mile Island, Chernobyl, and the Exxon Valdez were all ecological disasters caused in part by sleep deprivation on the part of workers.When researchers wake subjects up whenever they go into REM sleep, thus depriving them of this one particular stage, they find that soon, the person will try to go back into REM faster. Pretty soon, the researchers have to wake them up almost constantly. The increasing frequency of movement into REM within the sleep cycle is termed REM rebound, and it suggests that the body, for some reason, needs REM. The same rebound effect has been found for slow-wave sleep.
15Sleep Loss and Health Sleep loss can affect physiological processes Sleep restriction appears to trigger hormonal changes that increase hungerStudies have found a link between short sleep duration and increased obesityMortality rates are especially high among those who consistently sleep over 10 hours – F 5.10
16Figure 5.10. Mortality rates as a function of typical sleep duration.
17Sleep Deprivation effects 43 % of adults are chronically sleep deprivedMood shifts, decreased socialization & sense of humorDecreased motor and cognitive performanceReduced ability to concentrate and decision skillsReduced ability to handle complex tasksIncreased risk taking behavior and accidents (driving)Decreased efficiency of immune systemDecreased functioning of frontal lobesIncreased “microsleeps” and daytime sleepiness (43%)
18Sleep NeedsOn average, adults sleep 6 hours and 54 minutes during the workweek – recommended 8 hoursYounger adults (i.e., year-olds) sleep an average of 6 hours and 48 minutes during the week and an hour longer on the weekendAdolescents need 9.25 hours of sleep – 20 % fall asleep in schoolYounger children require 10 or more hours of sleep“Power Nap” minutes of duration“Power Sleep” – strategies for better sleepTakes about four weeks to stabilize sleep cycle
19Sleep ProblemsA majority of adults in the U.S. (62%) experienced a sleep problem a few nights per week or more during the past year. (Sleep Ominbus Survey 2000)Insomnia – difficulty falling or staying asleep - (58%) – F 5.11, F 5.12Narcolepsy – falling asleep uncontrollablySleep Apnea – reflexive gasping for air that awakens - (10%) – current estimates: 21 million in US and 470 million in the worldNightmares – anxiety arousing dreams - REMNight Terrors – intense arousal and panic - NREMSomnambulism – sleepwalkingSleep disorders are quite varied. The most common, however, is insomnia.Insomnia occurs in 3 different patterns…trouble falling asleep, trouble remaining asleep, and persistent early morning awakening. Difficulty falling asleep is most common among young people, while early morning awakening and trouble staying asleep are more common among middle-aged and elderly people.Estimates of the prevalence of insomnia vary, but it appears that about 34-35% of adults report problems with insomnia and about 15-17% have severe or frequent insomnia. The prevalence increases with age and is 50% more common in men than in women. Some people think they have insomnia, when they really have sound patterns of sleep – pseudoinsomnia or sleep state misperception.Narcolepsy is marked by sudden and irresistible onsets of sleep during normal waking hours. Interestingly, the person with Narcolepsy goes directly into REM sleep.Sleep apnea involves frequent, reflexive gasping for air that periodically occurs, waking the person who has it. With sleep apnea, the person literally stops breathing for 15 to 60 seconds…can cause heart and lung damage.Nightmares usually occur in REM sleep and are anxiety-arousing dreams.Night terrors are associated with non-REM sleep and are characterized by intense autonomic arousal and feelings of panic…more common in children…not indicative of emotional disturbance.
21Figure 5.13 – Sleep problems and the cycle of sleep
22Dreams and Dreaming: Content and Significance Dreams – mental experiences during sleepContent usually familiarCommon themes – F 5.14Waking life spillover – day residueWestern vs. Non-Western interpretationsFreud – wish fulfillment – manifest content and latent content – F 5.15Hobson & McCarley – activation – synthesis hypothesis – F 5.15Dreams are conventionally defined as mental experiences during REM sleep that are often based in vivid imagery, have a storylike quality, are often bizarre, and seem real to the dreamer. Many recent theorists have, however, questioned almost every aspect of this definition. We know now that people dream in non-REM too, although the dreams are less story-like and vivid in imagery. Also, recent research shows that content is usually not bizarre, and that dreamers are often aware that they are dreaming. Thus, the scientific conceptualization of dreaming is changing.Research shows that the content of dreams is usually familiar. Common themes in dreams include things like falling, being pursued, trying repeatedly to do something, school, sex, being late, eating, being frightened, etc. Children’s dreams appear to differ from those of adults, with preschool children reporting bland images with no story lines when awoken from REM sleep (if they recall dreaming at all – children under the age of 9-11 report dreaming only 20-30% of the time when awoken from REM sleep, as opposed to an adult’s 80% of the time). Between 5 and 8, children begin to report dream narratives, but these are not well developed. Adultlike dreams develop at around 11-13, suggesting that dreaming is a cognitive ability that develops gradually.Freud said that the contents of waking life tend to spill into dreams; he called this day residue.People in Western cultures pay little attention to dreams as meaningful messages in their lives, while people from many non-Western cultures are likely to view dreams as important information about themselves, the future, or the spiritual world.
24Hypnosis: Altered State of Consciousness or Role Playing? Hypnosis = a systematic procedure that increases suggestibilityHypnotic susceptibility: individual differences – F Stanford Hypnotic Susceptibility ScaleHilgrad’s neural disassociation (hidden observer)and Barber’s role theoryEffects produced through hypnosis:AnesthesiaSensory distortions and hallucinationsDisinhibitionPosthypnotic suggestions and amnesiaHypnosis is a systematic procedure that typically produces a heightened state of suggestibility as well as relaxation, narrowed attention, and enhanced fantasy.People differ in how easily they can be hypnotized…this is termed hypnotic susceptibility…10% of people are especially easy to hypnotize, 10% especially difficult…can be reliably measured with the Stanford Hypnotic Susceptibility Scale.Susceptibility linked to higher levels of absorption in a task and in a person’s imaginativeness…greatly depends on expectations. Research shows that people who are highly susceptible to hypnosis are just as responsive to suggestion without being hypnotized – Kirsch and Braffman (1999) call this imaginative suggestibility and argue that future research should focus on this broader trait.Phenomena that can be produced through hypnosis are many, including experiences such as anesthesia during medical or dental procedures, hallucinations (seeing, hearing, feeling, tasting, or smelling something that is not there), disinhibition (doing things you would normally be more inhibited about doing, like taking off your clothes in public), and posthypnotic suggestions and amnesia- influences of suggestions made during the hypnosis session on subjects’ later behavior (“you will remember nothing that occurred during your hypnotized state”).Researchers argue about whether hypnosis is really an altered state of awareness or if it is simply people doing what they think they are supposed to do when they are hypnotized…the dissociation hypothesis holds that hypnosis splits consciousness into two streams…divided consciousness.
26Sensory Deprivation and Meditation McGill University sensory deprivation study “Psychology of Boredom” – problems with participation and altered statesMeditation = practices that train attention to heighten awareness and bring mental processes under greater voluntary control – F 5.18Yoga, Zen, transcendental meditation (TM)Potential physiological benefitsSimilar to effective relaxation proceduresMeditation is an ancient discipline which has recently become an area of growing interest.Some of the most widely practiced forms of meditation are listed here. All three of these are rooted in Eastern religions; however, many who meditate do so separately from religious practice.Effects of meditation include decreased heart rate, respiration rate, etc., and a relaxed EEG, with predominant theta and alpha rhythm patterns. New research using the CT scan to track blood flow in the brain in experienced Tibetan Buddhist meditators shows high activity in the prefrontal cortex (an area important for focused attention) and low activity in parts of the parietal lobe that are known to process information about the body’s location in space…this may explain some of the transcendent experiences reported by many meditators.Meditation results in a potentially beneficial physiological state whereby bodily arousal is suppressed, but it is unclear how meditation differs from other systematic relaxation training procedures which produce very similar effects.
27Principal Abused Drugs and Their Effects ■ 6 categories of psychoactive drugs – Table 5.2Narcotics (opiates) – pain relieving - OxyContinSedatives – sleep inducing – effects GABAStimulants – increase CNS activity – effects on dopamine – F 5.19, methamphetamineHallucinogens – distort sensory and perceptual experienceCannabis – produce mild, relaxed euphoria – F 5.21Alcohol – produces relaxed euphoria, decreases in inhibitionsMDMA – “Ecstacy” produces a warm, friendly euphoria – problems of temperature regulation – effects serotoninBrain reward pathways – dopamine and limbic system – Figure 5.20Drug dependency and tolerance – physical and psychological – Table 5.3Psychoactive drugs: modify mental, emotional, or behavioral functioning…Recreational drug use: pleasurable alterations in consciousness.The 6 categories of drugs listed on the slide are frequently used recreationally.Narcotics include heroin, morphine, codeine, Demerol, and methadone…high doses produce an overwhelming sense of euphoria… a “who cares” quality.Sedatives include barbiturates…downers…used in higher doses than are prescribed for medical purposes.Stimulants include mild drugs such as caffeine and nicotine, as well as much stronger drugs such as cocaine and amphetamines. Cocaine and amphetamines have similar effects, except amphetamines last longer. The euphoria created by these drugs is very different from a “who cares,” very relaxed state - more like an “I can conquer the world,” very alert state of being.Hallucinogens such as LSD, mescaline, and psilocybin have similar effects including producing euphoria, increasing sensory awareness and a distorting sense of time. These experiences may be pleasant, but they can also produce nightmarish feelings of anxiety and paranoia…a bad trip.Cannabis is the hemp plant from which marijuana, hashish, and THC are derived. THC, the active chemical ingredient, causes a mild,relaxed euphoria and enhanced sensory awareness. Unintended effects can be anxiety, sluggish mental functioning, and memory impairment. New research shows that long-term marijuana use may impair some aspects of cognitive functioning, even when users are no longer high.Alcohol is the most widely used psychoactive drug. When people drink heavily, the effect is a relaxed euphoria that temporarily boosts self-esteem and decreases inhibitions.MDMA (ecstasy) is a compound drug related to both amphetamines and hallucinogens – became popular in US in the 1990s at raves and dance clubs. Research shows that ecstasy use may have long-term cognitive and emotional effects, but more research is needed.
30Figure 5.19 – Stimulant drugs and neurotransmitter activity Figure 5.20 – The “reward pathways” in the brain
31Questions about Sleeping and Dreaming Variations in length of sleep – F 5.22Suggestions on improving quality of sleep – F 5.23Anxiety and sleep difficulties – F 5.24 – possible classical conditioningThinking and insomnia – F 5.25Alcoholism a disease ?Malfunctions as a result of acoholism – F 5.26Genetic basisLearned behaviorsProblems with a definition of a “disease”
32Figure 5.26 - Physiological malfunctions associated with alcoholism