Consciousness and the Two-Track Mind Chapter 3
Key Concepts • Awareness • Much of what our brain does is done without our conscious awareness. • Attention • Divided attention, selective attention • Sleep • Stages of sleep • Why do we sleep? • Dreams • What are dreams and why do we have them? • Disorders of Sleep • Hypnosis
Processing The unconscious mind processes information simultaneously on multiple tracks, while the conscious mind processes information sequentially. Much of what are brain does is done without our conscious awareness Conscious Mind Unconscious Mind
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Attentional Processes • Selective Attention • The ability to focus awareness on a single stimulus to the exclusion of other stimuli • Cocktail party phenomenon • Divided attention • The ability to distribute one’s attention and simultaneously engage in two or more activities
Daydreams • Imaginary scenes & events that occur while awake • When do they happen? • Possible functions: • Mental rehearsal • Mental arousal when bored • Problem solving (practical & creative) • Pleasure
Biological Rhythms • Periodic fluctuations in physiological functioning • Four cycles: • Yearly • 28-day • Circadian (24 hours) • 90 minutes (sleep cycle)
Circadian Rhythm • A 24 hour cycle of varying Arousal and awakeness. • Influences sleep & wakefulness • As well as: • Blood pressure • Hormones • Body temperature – rises close to Morning, peaks midday, drops Before sleep • Suprachiasmatic nuclei (SCN) part of the hypothalamus • Light tells the SCN to decrease melatonin from the pineal gland (morning) and increase it at night fall. • Drifting toward a 25 hour cycle because of technology
Other biological rhythms • Ultradian Rhythm – Those that occur more than once each day. Include cycles of appetite and hormonal release. • Infradian rhythm – those that occur once per month. • Annual cycles (see next slide)
Annual Cycles • On an annual cycle, geese migrate, grizzly bears hibernate, and humans experience seasonal variations in appetite, sleep, and mood. • Seasonal Affective Disorder (SAD) is a mood disorder people experience during dark winter months related to lack of sufficient exposure. • Almost no one who lives at the equator suffers from SAD • 1 percent of Florida residents • 4 percent of Washington, D.C., residents • 9 percent of Alaska residents.
Sleep IQ Test 1. During sleep your brain rests. 2. You can not learn to function normally with one or two fewer hours of sleep a night than you need. 3. Boredom makes you feel sleepy, even if you have had enough sleep. 4. Resting in bed with your eyes closed cannot satisfy your body’s need for sleep. 5. Snoring is not harmful, as long as it doesn’t disturb others or wake you up. 6. Everyone dreams at night.
Sleep IQ Test 7. The older you get, the fewer hours of sleep you need. 8. Most people don’t know when they are sleepy. 9. Raising the volume of your radio will help you stay awake while driving. 10. Sleep disorders are mainly due to worry or psychological problems. 11. The human body never adjusts to night shift work. 12. Most sleep disorders go away, even without treatment.
Sleep IQ Answers 1. During sleep your brain rests. False: While your body rests, your brain doesn’t. 2. You can not learn to function normally with one or two fewer hours of sleep a night than you need. True: Sleep need is biological. While children need more sleep than adults, how much sleep any individual needs is genetically determined. 3. Boredom makes you feel sleepy, even if you have had enough sleep. False: Boredom only unmasks sleepiness, but it doesn’t cause it.
Sleep IQ Answers 4. Resting in bed with your eyes closed cannot satisfy your body’s need for sleep. True: Sleep is as necessary to health as food and water, and rest is no substitute for sleep. 5. Snoring is not harmful, as long as it doesn’t disturb others or wake you up. False: Snoring may be a signal for sleep apnea (which can be fatal if untreated). 6. Everyone dreams at night. True: Every person dreams every night – it’s just that some of us can’t remember much of our dreams.
Sleep IQ Answers 7. The older you get, the fewer hours of sleep you need. False: Although we tend to sleep less, our need for sleep doesn’t decrease as we age. 8. Most people don’t know when they are sleepy. True: We are not very good judges of our biological need for sleep. 9. Raising the volume of your radio will help you stay awake while driving. False: The only short-term solutions are to pull over and take a nap or to have a caffeinated drink.
Sleep IQ Answers 10. Sleep disorders are mainly due to worry or psychological problems. False: Sleep apnea is caused by relaxed muscles and narcolepsy appears to be genetic. 11. The human body never adjusts to night shift work. True: No matter how long you work a night shift, sleeping during the day remains a challenge because of our circadian rhythms that operate on the light/dark schedule. 12. Most sleep disorders go away, even without treatment. False: On average, sleep disorders do not disappear without treatment.
The Stages of Sleep • 5 stages, characterized by different brain activity • First four stages are non-REM • Fifth, and final, stage is REM • We pass through a cycle of the 5 stages about every 90 minutes, or about 4 to 6 cycles per night. As sleep continues the amount of time spent in each stage changes.
Awake and Alert • During strong mental engagement, the brain exhibits low amplitude and fast, irregular Beta waves (15‐30 cps). An awake person involved in a conversation shows beta activity.
Awake but Relaxed When you close your eyes but remain awake, brain activity slows to Alpha waves, large amplitude, slow and regular. • A meditating person exhibits alpha waves in their brain
Stage 1 • Light sleep lasting about 10 minutes • As you start this stage, brain waves go from beta to alpha to theta (by end of stage) • This is the transition from relaxed wakefulness to sleep • You can be easily awakened and may think you had not been asleep at all • May experience hallucinations (sensory experience with sensory stimulus) and hypnagogic sensations such as the sensation of falling or floating.
Stage 2 • About 20 minutes • More deeply relaxed but still light sleep (still showing theta waves) and can be easily awakened • Characterized by the appearance of Sleep Spindles • Bursts of rapid, rhythmic brain-wave activity • Sleep talking can occur.
Stage 3 and 4 • Stage 3 is transitional stage lasting a few minutes • Stage 3 and 4 together last about 30 minutes • Brain begins emitting big, slow delta waves in stage 3 and increasingly into stage 4. • Deep sleep • Sleepwalking and bedwetting occur toward the end of stage 4 • Nightmares, night terrors are also stage 4 sleep disorders
REM • Rapid Eye Movement • About an hour after falling asleep, you revert back through stages 3 and 2, and then enter REM sleep • Brain activity during REM resembles stage 1 but heart rate rises, breathing rate becomes rapid and irregular, and eyes dart around every half minute or so (mark beginning of a dream). • Marked by more vivid, detailed, and storylike dreams • We dream during all stages but these are more visual
REM • Approx. 4 to 6 cycles per night • The first time through the cycle, you only spend about 10 minutes in REM – this increases to 30 to 60 minutes by the last cycle • Called Paradoxical Sleep because the brain, including the motor cortex is active but the brainstem blocks its messages to the body – sleep paralysis Brain in Non-REM sleep, experiencing mild auditory stimulation Brain in REM sleep
90 Minute Sleep Cycles • With each 90‐minute cycle, stage 4 sleep decreases and the duration of REM sleep increases. • When deprived of sleep and then allowed to sleep, we experience REM Rebound
Question? What is it that makes us sleepy? Is it physical exertion or mental exertion?
Why do we sleep? • Sleep and Memory, Learning, and Creative thinking • Sleep and Growth • During sleep, the pituitary gland releases growth hormone • Older people release less hormone and sleep less • Restorative theories • Sleep rejuvenates us, helps restore brain tissue • Amount of slow wave sleep depends on how long we’ve been awake • Circadian theories • Evolutionarily, it has survival value, • Neural mechanism evolved over time to minimize exposure to predators and conserve energy. • This theory supported by the fact that there are species-specific differences in sleep patterns.
What happens When We Are Deprived of Sleep? • Fatigue and eventually death, if sleeplessness continues past as certain point • Impaired concentration/cognitive function • Emotional irritability. • Depressed immune system. • The hormones cortisol and ghrelin increase, and leptin decreases
Sleep and Accidents • Frequency of accidents increases with loss of sleep
What are dreams? • What are dreams? • Electrochemical events that involve the brainstem, areas of the cortex, and the eyes
What do we dream about? • Dream content • 8 out of 10 dreams have negative emotional content • Most common themes: falling, being chased/attacked, repeatedly trying but failing to do something • What influences the dreams we have • Concerns of your everyday life • External stimuli • Yourself • Lucid dreaming
Why do we dream? • Wish fulfillment (Freud) • Manifest content • Latent content • Activation-synthesis (Hobson & McCarley) • Activation: random neural signals firing in the brainstem that spread up to the cortex • Synthesis: the brain then creates images and stories in an effort to make sense out of these random signals • Information Processing • Dreams help sift through a days experience and fix it in our memory
Why Do We Dream? Physiological Function • Dreams provide the sleeping brain with periodic stimulation to develop and preserve neural pathways. • Neural networks of newborns are quickly developing; therefore, they need more sleep.
Sleep Disorders • Insomnia • Chronic problems in getting good sleep • Difficulty in falling asleep, staying asleep • Causes • Stress, depression, health problems • Solutions • Sedatives aren’t always effective and should never be a long-term solution • Don’t take naps during the day • Avoid caffeine and don’t exercise close to bed time • Practice good sleep hygiene
Sleep Disorders • Hypersomnia • Being sleepy during the day and sleeping too much at night • Narcolepsy – overpowering urge to fall asleep that may occur during walking or standing or be triggered by stress • Parasomnias • Sleep apnea – breathing stops during sleep and the person is repeatedly awakened by oxygen deprivations • Nightmares • Night terrors – sudden arousal from sleep with intense fear, mostly in children • Sleepwalking (somnambulism)
Hypnosis • A social interaction in which one person suggests to another that certain behaviors, perceptions, feelings or thoughts will spontaneously occur. • Ernest Hilgard - Hypnosis involves social influence and a state of dissociation – a split between levels of consciousness • Two stages of hypnosis • Induction • suggestion
Hypnotic Susceptibility • Hilgard’s Stanford Hypnotic Susceptibility Scale • Roughly 10% highly hypnotizable • Roughly 10% not hypnotizable at all • Effects of hypnosis • Perceptual effects • Altering smells • Pain relief • Cognitive effects • Hypermnesia vs. psuedomemories • Behavioral effects • Posthypnotic suggestion – Suggestion carried out after the person is no longer hypnotised • Posthypnotic amnesia – supposed inability to recall what one experienced while hypnotised
Is hypnosis an altered state of consciousness? Social Influence Theory: • Hypnotic subjects may simply be imaginative actors playing a social role. Divided Consciousness Theory: • Hypnosis is a special state of dissociated (divided) consciousness (Hilgard,1986, 1992). Hilgard, 1992
The Third Man Factor • There have been stories of people at the very edge of death, often adventurers or explorers, who experience a sense of an incorporeal being beside them who encourages them to make one final effort to survive. • Is this hallucination? A form of self hypnosis? An extreme coping mechanism? • One study of cases showed that the largest group of people who have experienced it involved climbers, followed by solo sailors and shipwreck survivors, followed by polar explorers. • Is this at all related to childhood imaginary friends?
Third Man Factor • Shared phenomenon: Sir Ernest Shackleton (second from left) and his team all sensed another person with them while on a treacherous Antarctic expedition
Chemically Altered Consciousness • Psychoactive drugs • Induce changes in thinking, perception & behavior by affecting neuronal activity in the brain • Four general categories • Depressants • Stimulants • Hallucinogens • Opiates
Dependence & Addiction • Continued use of a psychoactive drug produces tolerance. With repeated exposure to a drug, the drug’s effect lessens. Thus it takes greater quantities to get the desired effect.
Expectations • The effect that any drug has on mood or behavior is also influenced by a person’s expectations of how that drug will effect them.
Withdrawal & Dependence • Withdrawal: Upon stopping use of a drug (after addiction), users may experience the undesirable effects of withdrawal. • Dependence: Absence of a drug may lead to a feeling of physical pain, intense cravings (physical dependence), and negative emotions (psychological dependence).
Depressants Depressants are drugs that reduce neural activity and slow body functions. They include: • Alcohol • Barbiturates • Opiates
Alcohol Alcohol affects motor skills, judgment, and memory…and increases aggressiveness while reducing self awareness.
Barbiturates Drugs that depress the activity of the central nervous system, reducing anxiety but impairing memory and judgment. Nembutal, Seconal, and Amytal are some examples.
Opiates Opium and its derivatives (morphine and heroin) depress neural activity, temporarily lessening pain and anxiety. They are highly addictive.
Stimulants Stimulants are drugs that excite neural activity and speed up body functions. 1. Caffeine 2. Nicotine 3. Cocaine 4. Ecstasy 5. Amphetamines 6. Methamphetamines