Download Consciousness & Its Variants

Consciousness & Its Variants
Psychology 2012 – Spring 2004
Consciousness
• Personal awareness of mental activities,
internal sensations, and the external
environment
– William James called it a “stream” of
consciousness
• Always changing, yet flowing in an unbroken
manner
Biological & Environmental
“Clocks”
• Circadian rhythm – a cycle that is roughly 24
hours long
• Examples of Human Circadian Rhythms
–
–
–
–
–
Peak mental alertness – around 9 AM & 9 PM
Peak physical strength – around 11 AM & 7 PM
Lowest sensitivity to pain – around 3 PM-5 PM
Highest sensitivity to pain – around 3 AM-5 AM
Peak degree of sleepiness – around 3 AM & 3 PM
Biological & Environmental
“Clocks”
•
Two mechanisms influence sleep
1. The suprachiasmatic nucleus (SCN) – a cluster of
neurons in the hypothalamus in charge of the timing
of the sleep-wake cycle and the mental alertness
cycle
2. Eyes detect a decrease in light, and melatonin
production is increased
•
Melatonin – hormone produced by the pineal gland that
makes us more sleepy and reduce our activity levels
–
–
Production of melatonin typically peaks between 1AM-3AM
Production of melatonin typically slows right before sunrise
Biological & Environmental
“Clocks”
• Free-running circadian rhythms – rhythms that are not
allowed to be affected by environmental cues like
sunlight and clocks
– People begin to move toward a 25 hour rhythm
– When sunlight and clocks are allowed back in, people
go back to a 24 hour rhythm within days
• Circadian rhythms and sunlight – what happens when
your internal clock is not matched up with environmental
cues?
– Jet lag may result
• Thinking, concentration, & memory get fuzzy
• Fatigue, depression, irritability, & disrupted sleep
Biological & Environmental
“Clocks”
• Why jet lag?
– Major reason = melatonin is out of alignment
with the environment
• 10 AM in London = 3 AM in Denver
– Instead of feeling refreshed, you feel groggy and sleepy
Sleep
• Electroencephalograph – device invented in the
1920’s that measures and records the brain’s
electrical activity
• REM sleep – type of sleep during which there is
rapid eye movements and dreaming, and
voluntary muscle movement is suppressed
– AKA active sleep or paradoxical sleep
• NREM sleep – quiet, usually dreamless sleep
divided into four stages
– AKA quiet sleep
The Onset of Sleep
• Beta brain waves – brain wave pattern associated
with alert wakefulness
• Alpha brain waves – brain wave pattern
associated with relaxed wakefulness
– Hypnagogic hallucinations – vivid sensory phenomena
that can occur during the onset of sleep
• Common = sensation of falling, often accompanied by a
myoclonic jerk
Stages of Sleep
• Stage 1 NREM – begins when beta brain waves begin to be
replaced by slower theta waves; lasts only a few minutes
– Easily awakened
– Often some images of normal, daily activities are reported
• Stage 2 NREM – represents the onset of true sleep; theta
waves w/ some delta waves (slower, larger waves)
– Characterized by short bursts of brain activity called sleep
spindles
• Last about a second or two
• Stage 3& 4 NREM – very similar; characterized by delta brain
waves
– Blood pressure, heart rate, breathing at their lowest levels
– Difficult to wake up if awoken during these stages
– AKA as slow wave sleep
Stages of Sleep
• REM sleep – visual and motor neurons in the
brain fire repeatedly just as they do when awake;
the sleeper’s eyes dart back and forth behind the
eyelids
– Voluntary muscle activity is suppressed
– After the first 90 minutes of sleep, REM periods
become longer and NREM periods become shorter
Changes in Sleep Patterns
Across the Lifespan
• Over the course of
our lives, the
quantity and quality
of our sleep changes
– Time spent sleeping
= decreases
– Time in slow wave
NREM sleep =
decreases
Why Sleep?
• Sleep deprivation studies – participants are not
allowed to sleep
– REM deprivation – participants are allowed to sleep,
but are awakened when REM sleep begins
• REM rebound – when allowed to sleep uninterrupted, the
amount of time spent in REM sleep increases
– NREM deprivation – participants are allowed to sleep,
but are awakened when stages 3&4 NREM sleep
begins
• NREM rebound – when allowed to sleep uninterrupted, the
amount of time spent in stages 3&4 NREM sleep increases
Sleep Theories
• Restorative theory of sleep – theory that sleep
promotes physiological processes that restore &
rejuvenate the body & the mind
– NREM – restores the body
– REM – restores mental and brain functions
• Adaptive theory of sleep – theory that sleep
patterns evolved over time to help promote
survival and adaptation to the environment
– AKA evolutionary theory of sleep
More Sleep Disorders
• Sleep bruxism – person grinds the teeth loudly
during sleep
• REM sleep behavior disorder – person acts out
his or her dreams
– May be caused by damage in the lower brain centers
that control physical & mental arousal during sleep
• Parasomnias – category of sleep disorders that
involve arousal or activation during sleep or sleep
transition
– Sleepwalking, night terrors, sleep bruxism, REM sleep
behavior disorder
Dreams and Mental Imagery
During Sleep
•
•
Sleep thinking – repetitive and uncreative
thoughts about real-life events during sleep
Dream – a storylike episode of mental imagery
during sleep
– J. Allan Hobson – dreams have 5 basic
characteristics
1.
2.
3.
4.
5.
Emotions are intense
Content and organization are typically illogical
Sensations can be strange
Strange details are accepted without question
Images are often difficult to remember
Dreams and Mental Imagery
During Sleep
•
The brain during REM sleep – brain activity is
different than when awake or when in NREM
sleep
–
Primary visual cortex and frontal lobes are shut
down
•
–
This cuts people off from information about the external
world and from centers of rational thought
Amygdala and hippocampus are highly active
•
Structures in the limbic system involved with emotion &
memory
Dreams and Mental Imagery
During Sleep
•
REM & memory consolidation – studies have
shown that REM sleep increases after learning a
new task
–
•
And that disrupting REM sleep after training disrupts
learning
What do we dream about?
–
Researcher Calvin Hall states that dreams often
reflect the daily concerns of the dreamer
– Certain dream themes, such as falling, being chased,
and being attacked are common themes across
cultures
Dreams and Mental Imagery
During Sleep
•
Why don’t we remember our dreams?
–
Making remembering more likely
1. We are more likely to remember our dreams if we wake up
during them
2. The more vivid, bizarre, or emotionally intense a dream is,
the more likely we will remember them
3. Distractions upon awakening interfere with our ability to
recall dreams
– It is difficult to remember any experience during
sleep, not simply dreams
Dreams and Mental Imagery
During Sleep
• The significance of dreams – there are
many theories regarding dreams
– Sigmund Freud – founder of psychoanalysis;
thought that dreams were symbolic
representations of unconscious wishes and
urges
• Two components of dreams
1. Manifest content – the actual dream images
2. Latent content – the disguised meaning of the dream
images
Dreams and Mental Imagery
During Sleep
• Another theory regarding dreams
– The activation-synthesis model of dreaming –
dreaming is our subjective awareness of the
brain’s internally generated signals during
sleep
• Dreaming is due to activation of the brain stem,
which activates more sophisticated brain areas
– The brain then synthesizes the internally generated
signals into a dream
» Brain synthesizes memory fragments, emotions,
and internal sensations
Dreams and Mental Imagery
During Sleep
•
Another theory regarding dreams
–
The Gestalt Therapy approach – dreams are
“messages” that only you can interpret accurately
•
The role of the therapist = help the client to make rational
sense of the dream and decode the message
–
–
Decoded dreams can help clients become aware of more
information about themselves
The meaning of dreams – interpretation of dreams
may tell more about the interpreter than about the
meaning of the dream
Hypnosis
•
An unusual state of awareness in which a person
responds to suggestions with changes in perception,
memory, and behavior
–
–
Best candidates for hypnosis = those with positive, receptive
attitudes regarding hypnosis
Effects of hypnosis
• Sensory and perceptual changes – such as hallucinations,
temporary blindness, deafness, or loss of sensation in an
area
• Posthypnotic suggestions – a suggestion made during
hypnosis that the person carry out a specific instruction
following the hypnotic session
Hypnosis
•
Hypnosis and memory – hypnosis can affect
memory in many ways
Posthypnotic amnesia – memory is suppressed by a
hypnotic suggestion
2. Pseudomemories – hypnosis can greatly increase
confidence in false memories
3. Hypermnesia – claims have been made that
hypnosis can improve memory
1.
–
There is currently no proof that hypnosis improves memory
Hypnosis
•
Explaining hypnosis – psychologist Ernest
Hilgard believes that the hypnotized person
experiences dissociation
–
–
The splitting of consciousness into two or more
streams of mental activity
The neodissociation theory of hypnosis
•
•
Hypnotized person consciously experiences the hypnotist’s
suggestions and
Another stream of consciousness is dissociated and
processing unconscious information
–
“Hidden observer”
Meditation
•
One of a number of concentration techniques
that focus attention and heighten awareness
–
Two basic categories
1.
Concentration techniques – focusing your awareness on
something
•
2.
–
Your breath, a word, a visual image
Opening up techniques – paying attention to the present
moment without judging it in any way
Effects of meditation – there are many effects of
meditation
•
Lower physiological arousal
–
Lower blood pressure, decreased heart rate, changes in brain
waves (alpha brain waves)
Psychoactive Drugs
• Drugs that alter consciousness, perception,
mood, and behavior
– Common properties of psychoactive drugs
• Addiction – a state of feeling psychologically
and/or physiologically compelled to take a specific
drug
Psychoactive Drugs
• Common properties of psychoactive drugs, continued
– Physical dependence – a condition in which a person’s body and
brain have adapted to the drug
• Tolerance – a state of needing more of the drug in question in order
to achieve the original effect of the drug
• Withdrawal symptoms – unpleasant physical reactions to the lack of
a drug, along with intense craving for the drug
– Drug rebound effect – withdrawal symptoms that are opposite
of the drug’s original effect
» E.g., stimulating drugs = fatigue and depression; depressant drugs
= excitability and nervousness
• Drug abuse – recurrent drug use that results in disruptions
in academic, social, or occupational functioning
– Or in legal or psychological problems
Psychoactive Drugs
• Alter consciousness by influencing
neurotransmitters
• Many illegal, or legal only for
medical uses
Drug Categories
• Depressants
• Stimulants
• Hallucinogens/Psychedelics
• Narcotics
Depressants
• Slow down the Central Nervous
System (CNS)
– alcohol
– barbiturates
– tranquilizers (benzodiazapines)
– sedatives
Alcohol Effect
#
D
R
I
N
K
S
•
•
•
•
•
•
Death
Unconsciousness
Loss of motor control
Clouded judgement
Reduced motor skills
Reduced inhibitions
Alcohol
• 14 million Americans have alcohol problems
– 7 million considered alcoholic
• Low level of dependence = certain withdrawal
symptoms
– Disrupted sleep, anxiety, tremors
• Higher level of dependence = more severe
withdrawal symptoms
– Confusion, hallucinations, severe tremors/seizures,
even death
• Delirium tremens “DTs”
Barbiturates
• Death (overdose is easy)
A
m
o
u
n
t
• Unconsciousness
• Loss of motor control
• Clouded judgement
• Slowed reactions
Tranquilizers
• Mild CNS depressants
• Rarely used recreationally
• Can be fatal if used with alcohol
How Depressants Work
Barbiturates, sedatives
Attaches to
GABA
receptors
Slows firing of
CNS neurons
Stimulants
• Speed up the CNS
– amphetamines
– cocaine
– nicotine
– caffeine
Amphetamines
High
Doses
Paranoia, confusion,
damage to brain
capillaries
Low
Doses
Reduced fatigue,
increased energy,
reduced appetite
Cocaine
High
Doses
Paranoia, irregular
heartbeat, death
Low
Doses
Intense,
short-term euphoria
Nicotine
• Mildly stimulating, quite addictive,
highly toxic
• Associated with a wide variety of
illnesses
Caffeine
High
Doses
Causes hostility,
anxiety, “jitteriness”
Low
Doses
Mild stimulant.
Increase alertness.
More Psychoactive Drugs
• Stimulants
– Caffeine – increases mental alertness &
wakefulness
• Found in coffee, tea, cola, chocolate, and many
over-the-counter drugs
• Most widely used psychoactive drug in the world
– Nicotine – increases mental alertness and
reduces fatigue
• Found in tobacco products
How Stimulants Work
Cocaine, amphetamines
Reduced
dopamine
reuptake
Pleasurable
sensations
Reduced
norepinephrine
reuptake
Alertness,
activity
Hallucinogens/Psychedelics
• Cause sensory distortions, hallucinations
– LSD
– PCP
– mescaline
– marijuana
LSD
• Causes marked visual hallucinations, sensory distortions
• Induces powerful emotional feelings
• Negative hallucinations and emotions can lead to suicide, panic, or
dangerous actions
• Flashbacks (a return of the hallucinations) may occur days, months, or
years later
Marijuana
• Relieves anxiety, inhibitions
• Reduces memory performance
PCP
High
Doses
Tactile hallucinations,
magnification of senses
Low
Doses
Mild euphoria
Narcotics
• Derivatives of the opium poppy
• Reduce pain, cause euphoria
– heroin
– morphine
– opium
– codeine
Heroin
• Produces powerful euphoria, deadens
pain
• Highly physiologically addictive
• Attaches to endorphin sites
• Causes death in large doses
Morphine & Codeine
• Highly effective pain killers
• Addictive when used recreationally,
not highly addictive when used just
to relieve pain
How Narcotics Work
Heroin, morphine
Attaches to
endorphin
sites
Slows firing of
pain neurons