Subject Announcements
pool credits [e-mail]
Pw: psychology o Assignments for psy major o Guide: http://bcs.worthpublishers.com/Psych2go/?uid=0&rau=0
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Mid-term exam
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Grades
Mean=70, max=99, min=22; Pass rate=70%
Mean(psy)=76; mean(non-psy)=63. Individual grades Tuesday afternoon
(B508-2)
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Makeup? Absence Cheating!
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Grade distribution
grades 50 45 40 35 30 25 20 15 10 5 0 20 30 40 50 60 70 80 90 grades
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Chapter 5: Consciousness
Li Yi Nov. 16, 2009
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Outline
Nature of consciousness Biological Rhythms Sleep and waking cycle Dreams Hypnosis Meditation Mind-Altering Drugs
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Consciousness: Personal Awareness
Awareness of external and internal stimuli
o o o o
A car is coming. My heart beats fast. I did not realized that a car is coming. William James stream of consciousness
Contents of consciousness are continually changing
Theories of awareness
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Sigmund Freud unconsciousness
Peoples feelings and behaviors are influenced by the UC needs & wishes.
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Levels of Consciousness
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Conscious level
A level of mental activities that people are aware of
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o o
Nonconsicous level
A level of mental activity inaccessible to conscious awareness Biological processes (e.g. pulse regulation)
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Preconscious level
Outside of awareness, but can easily be brought into awareness with attention o e.g. what did you have for dinner last night?
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o o
Unconscious (or subconscious) level
Mental activities are difficult to bring into awareness Can alter thoughts, feelings and actions.
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Research on Consciousness
Priming effect without awareness People remain aware of external events to some degree (Campbell, 2000; Evans, 1990)
e.g. New parents
Awake under anesthesia for surgery (Merikle, 2007)
Awake (2007)
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Consciousness & Brain Activity
The Electroencephalograph (EEG): A Physiological Index of Consciousness EEG () monitoring of brain electrical activity Brain-waves
o o
Amplitude (height) Frequency (cycles per second-cps)
Beta - (13-24 cps) Alpha - (8-12 cps) Theta- (4-7 cps) Delta- (<4cps)
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Figure 5.1 The correlation between mental states and electrical activity in the brain. As discussed in Chapter 2, correlations () alone do not establish causation. For example, there are strong correlations between drowsiness and a particular pattern of cortical activity, as reflected by EEG brain waves. But does drowsiness cause a change in cortical activity , or do changes in cortical activity cause drowsiness? Or does some third variable account for the changes in both? 25
Outline
Nature of consciousness Biological Rhythms Sleep and waking cycle Dreams Hypnosis Meditation Mind-Altering Drugs
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Biological Rhythms and Sleep
Circadian Rhythms 24 hr biological cycles Regulation of sleep/other body functions
fall asleep as body temperature drops and wake when ascending o blood pressure, urine production (), hormonal () secretion o Circadian rhythms generally7 persist even when external time cues are eliminated.
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Figure 5.2 Examples of circadian rhythms. These graphs show how alertness, core body temperature, and the secretion of growth hormone typically fluctuate in a 24-hour rhythm. Note how 28 alertness tends to diminish with declining body temperature.
Biological Rhythms and Sleep
Ignoring Circadian Rhythms (CR)
Sleep at unusual time Poor quality of sleep fatigued () sluggish () irritable () o Jet lag rule of thumb
o o
easier to fly westward (lengthen your day) than eastward (shorten it) readjustment process-one day per time zone when flying eastward 2/3 day per time zone when flying westward
readjustment melatonin () for jet lag, insomnia (), and other sleep disorders
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Figure 5.3 Circadian rhythms and jet lag. Jet lag can be assessed in a variety of ways. In a study of people flying between Detroit and London, which requires a 5-hour time shift, Nicholson et al. (1986) looked at the time it took travelers to fall asleep the night before their trip and the next five nights after their flight. As you can see, subjects who flew eastward had increased difficulty falling asleep, whereas subjects who flew westward showed no evidence of jet lag on this measure. The data are consistent with other findings that air travelers generally adjust more slowly after flying east (which shortens their day) than after flying west (which lengthens it). 30
Outline
Nature of consciousness Biological Rhythms Sleep and waking cycle Dreams Hypnosis Meditation Mind-Altering Drugs
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Sleep and waking cycle
Stages of sleep Age Trends in Sleep Culture and sleep Neural bases of sleep Sleep Deprivation Sleep disorders
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Sleep/Waking Research Instruments and index
o o o o
Electroencephalograph (EEG)
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brain electrical activity muscle activity and tension
eye movements
ElectromyographEMG-
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Electrooculograph EOG- Other bodily functions also observed
o o o o
Heart rate Breathing Pulse rate Body temperature
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Sleep Stages: Cycling Through Sleep
Feature o Onset is gradual--- no obvious transition points o Average 25 min o factors
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Sleep Stages: Cycling Through Sleep
Stages
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Stage 1: brief, transitional (1-7 minutes)
breathing, heart rate and muscle decline tension alpha -> theta hypnic jerks
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Stage 2: sleep spindles (10-25 minutes)
Respiration , heart rate, muscle tension and body temperature decline further Higher frequency brain wavessleep spindles
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Sleep Stages: Cycling Through Sleep
Stages o Stages 3 & 4 : slow-wave sleep (30 minutes) o High-amplitude, low-frequency delta waves
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Stage 5-REM(rapid eye-movement, ) EEG (beta waves) similar to awake high freq, low amplitude Deep, hard to awaken vivid and memorable dreaming irregular breathing and pulse rate, muscle tone extremely relaxed minimal body movement and virtually paralyzed ()
Sequence 1-2-3-4-1-5 ()/2-5 1 hour for stage 1-4 (non-REM, NREM)
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Figure 5.4 EEG patterns in sleep and wakefulness. Characteristic brain waves vary depending on ones state of consciousness. Generally, as people move from an awake state through deeper stages of sleep, their brain waves decrease in frequency (cycles per second) and increase in amplitude (height). However, brain waves during REM sleep resemble wide-awake brain 38 waves.
Figure 5.5 An overview of the cycle of sleep
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Age Trends in Sleep
New born
o 6-8 times everyday; > 16 hrs o REM longer (50/% in the first
3-5 months then 40%, 30%-20% in 3-5 years) sleep declines and Stages 1
Adult
o Slow-wave
increases o average time in sleep declines
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Figure 5.6 Changes in sleep patterns over the life span. Both the total amount of sleep per night and the portion of sleep that is REM sleep change with age. Sleep patterns change most dramatically during infancy, with total sleep time and amount of REM sleep declining sharply in the first two years of life. After a noticeable drop in the average amount of sleep in adolescence, sleep patterns remain relatively stable, although total sleep and slow-wave sleep continue to decline gradually with age. (Adapted from Roffwarg, Muzio, & Dement, 1966; revised by authors since publication) 41
Figure 5.20 Variation in sleep needs. Based on data from a variety of sources, Webb (1992b) estimates that average sleep length among young adults is distributed normally, as shown here. Although most young adults sleep an average of 6.5 to 8.5 hours per night, some people need 42 less and some people need more sleep.
Culture and Sleep
No much difference across culture in psychological and physiological experience of sleep
Average time of sleep Time it takes to fall asleep
Co-sleepingis more common in east Nap and siesta ()
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Figure 5.7 The ascending reticular activating system (ARAS)
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The Neural Bases of Sleep
Brain Structures: o Ascending reticular activating system (ARAS, ) o Pons -REM, o medulla , thalamus , hypothalamus , limbic system Neurotransmitters: o Acetylcholine (Ach ) o serotonin (5-) o norepinephrine (NE ), o dopamine, o GABA (r-) no sleep center and no sleep chemicals
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Launch Video
Figure 5.7 The ascending reticular activating system (ARAS). A number of brain areas and structures interact to regulate sleep and waking. Particularly important is the ARAS (represented by the 46 white arrows), which conveys neural stimulation to many areas of the cortex.
Sleep Deprivation
Complete deprivation
3 or 4 days max
Partial deprivation or sleep restriction
o o
Less sleep than normal for a period of time impaired attention, reaction time, motor coordination , and decision making
Selective deprivation
REM and slow-wave sleep deprivation: rebound effect o Memory consolidation
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Figure 5.8 Effect of sleep deprivation on cognitive performance. Experimental subjects in the Pilcher and Walters (1997) study underwent 24 hours of sleep deprivation prior to taking the WatsonGlaser Critical Thinking Appraisal. As you can see, their performance on this cognitive test was clearly inferior to that of the control subjects, who had not experienced sleep deprivation. 48
Sleep Problems
Insomnia
difficulty falling sleep initially (young) Difficulty in remaining asleep (elder) Early-morning awakening (elder)
Narcolepsy falling asleep uncontrollably during waking period
Wakefulness---REM Uncommon 0.05%; causes not clear
Sleep Apnea frequent & reflexive gasping for air that awakens a person and disrupts sleep.
Accompanied by loud snoring
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Sleep Problems
Nightmares anxiety-arousing dreams REM
Recall vivid dreams, difficult to fall asleep again Associated with daily stress 10% adults
Night Terrors intense arousal and panic
NREMstage 4 Do not recall dreams; easy to return to sleep
Somnambulism sleepwalking
15% children and 3% adults First 3 hours of sleep; slow-wave sleep
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Figure 5.12 Sleep problems and the cycle of sleep
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Figure 5.11 The vicious cycle of dependence on sleeping pills
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The vicious circle of anxiety and sleep difficulty. Anxiety about sleep difficulties leads to poorer sleep, which increases anxiety further, which in turn leads to even greater difficulties in 53 sleeping.
Thoughts and emotions associated with insomnia. This graph depicts the percentage of insomniacs and control subjects reporting various presleep feelings and thoughts. Insomniacs tendency to ruminate about their problems contributes to their sleep difficulties. (Based on data from Kales et al., 1984)
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