Transcript Consciousness

Consciousness
&
Altered States of Consciousness
Consciousness
Sleep
Hypnosis
Drugs
Definitions of Consciousness
Allow Its Empirical Study
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Subjectivity and “qualia”
– How do we know that your idea of red and my idea of red
are the same idea?
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Access to Information
– We have access to some information in our minds (i.e., our
consciousness), but we don’t have access to other
information in our minds (i.e., our unconscious)
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Unitary Experience
– The outputs of our sensory systems are unified into a
phenomenal experience that is continuous over time
Manipulating objects with the mind
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Implant small electrodes in the frontal and parietal
lobe of a monkey
Record electrical activity in those areas while the
monkey is using a joystick to manipulate a robotic arm
Create an “index” for the robotic arm, such that
certain patterns of brain activity indicate certain
movements
Unplug the joystick and make movement of the
robotic arm completely dependent on brain activity
Within days, the monkey was able to control the
robotic arm with only it’s thoughts
Variations in conscious experience
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Automatic vs. controlled processing
– Typically, automatic processing is fast and is done without
much conscious effort (e.g., driving on a dry highway
without much traffic)
– Typically, controlled processing is slower and is done with
conscious effort (e.g., driving on a wet highway with a lot of
traffic)
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Comas: vegetative to minimally conscious
– Brain imaging can help determine the nature of the coma
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Thalamic stimulation
The Corpus Callosum
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Millions of myelinated
axons connecting the
brain’s hemispheres
Provides a pathway for
communication between
the hemispheres
If surgically severed for
treatment of epilepsy,
hemispheres cannot
communicate directly
Visual Processing
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Both eyes send
information to
both hemispheres
Right half of the
visual field goes
to the left
hemisphere
Left half of the
visual field goes
to the right
hemisphere
Sperry’s Split-Brain Experiment
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Split-brain subjects
could not name objects
shown only to the right
hemisphere
If asked to select these
objects with their left
hand, they succeeded
but they could not say
why
The right side of the
brain doesn’t control
speech
The interpreter
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The left
hemisphere
likes to
construct a
world that
makes sense.
– It may even
seek patterns
that might
not exist.
Unconscious Processing
Influences Awareness
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The case for unconscious influence:
– Subliminal perception (see next slide)
– Freudian slips
– Priming
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The smart unconscious
– Incubation effects
– Verbal overshadowing
Blindsight
 Global workspace model of consciousness
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Subliminal Perception
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Priming is quicker retrieval
of words related to
previous stimuli
Priming works even if
previous words are
presented subliminally
– That is, the words are
presented in such a way that
the subject claims not to
have perceived them.
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This is more evidence for
the influence unconscious
processing on awareness.
Sleep and Dreams
Measuring Sleep
Stages of Sleep
Why Do We Sleep?
Dreams
Sleep Disturbances
Measuring Sleep
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Electrodes measure
– eye movements
– EMG
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Electromyogram
– EEG
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Electroencephalogram
A camera may also
record body movements
Stages of Sleep
A Typical Night’s Sleep
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Typically 4-5
episodes of REM
sleep per night
– Later episodes are
longer and farther
apart
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Most “deep sleep”
(stages 3 & 4)
occurs early
Sleep disorders
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Insomnia
– Pseudoinsomnia
– Worrying
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Cognitive-behavioral therapy can help
Sleep apnea
 Narcolepsy
 Sleepwalking (somnambulism)
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Why do we sleep:
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Restoration
– Sleep allows the body to repair itself.
– Sleep deprivation
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Microsleeps
Can cause problems with mood and cognitive performance
Circadian Rhythms
– Keep animals quiet and inactive during the most dangerous
part of the day (night for humans)
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Consolidation
– Neuronal connections that serve as the basis for new
learning is strengthened during sleep.
Who Sleeps How Much?
Dreams
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Recalling dreams is rare, but dreaming isn’t
– A normal person may dream 150,000 times in their lifetime
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People report dreams 80% of the time during REM
sleep, but less than 50% of the time during other
stages
– REM dreams are more bizarre; non-REM dreams are often
boring
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People have less REM sleep with age
– In newborns, 50% of sleep is REM
– In the elderly, about 20% of sleep is REM
What Do We Dream About?
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64% of dreams associated with
sadness, fear, or anger
– Aggressive acts outnumbered friendly acts
by 2:1
18% of dreams were happy or exciting
 29% of dreams were in color
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Dream Theories
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Sigmund Freud believed that dreams expressed
wishes, often disguised
– Manifest Content
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Conscious dream content that is remembered after awakening
– Latent Content
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The unconscious, uncensored meaning of a dream
Alan Hobson activation-synthesis theory
– Random activation from the pons and the amygdala activate
visual systems and memory systems and the mind attempts
to interpret these random patterns
Sleep Disturbances
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Insomnia
– Inability to fall asleep, stay asleep, or get
enough sleep to function during the day
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Hypersomnia (Narcolepsy)
– A type of; irresistible, sudden attacks of
drowsiness during the day
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Parasomnia (Sleep disturbance)
– Apnea: Repeated cessation of breathing
during sleep
Hypnosis
Hypnosis
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Hypnotic induction
– Attention-focusing procedures in which changes in a
person’s behavior or mental state are suggested
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Hypnotic Susceptibility
– The extent to which an individual is
characteristically responsive to hypnosis
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Posthypnotic suggestion
– A suggestion made to a subject in hypnosis to be
carried out after the induction session is over
Can Hypnosis Enhance
Eyewitness Testimony?
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Participants saw
videotape of a staged
bank robbery
Half were then
hypnotized
Re-intervivew mentioned
robber wore a mask
– There was no mask
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In highly hypnotizable
subjects, 63% had false
memories
The Hidden Observer
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Subjects held a
hand in ice water
and reported pain
Hypnotized subjects
reported lower pain
Hypnotized subjects
reported a “hidden
observer” that was
aware of the pain
How Do Drugs Affect
Consciousness?
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People Use—and Abuse—Many
Psychoactive Drugs
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Alcohol Is the Most Widely Abused
Drug
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Addiction Has Psychological and
Physical Aspects
People Use—and Abuse—
Many Psychoactive Drugs
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Marijuana
– most widely used illegal drug
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Stimulants
– Cocaine and amphetamines (speed, meth, etc.)
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improve mood
cause restlessness and disrupt sleep
MDMA (“ecstasy”)
– similar effects as stimulants, with slight hallucinations
Opiates
– Heroin, morphine, codeine
– Highly addictive due to dual activation of dopamine and
opiate receptors
Alcohol Is the Most Widely
Abused Drug
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Alcoholism is the third largest health problem,
following heart disease and cancer
– Currently 5% of all Americans are active alcoholics
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Another 3% are addicted to other drugs
– Lifetime prevalence is 10-20%
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Americans have a love/hate relationship with alcohol
– On the one hand, moderate drinking is an accepted aspect
of normal social interaction and may even be good for
health.
– On the other hand, alcohol is a major contributor to many of
our societal problems, such as spousal abuse and other
forms of violence.
Alcohol Is the Most Widely
Abused Drug
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Expectations
– alcohol reduces anxiety
– alcohol increases social skills, sexual pleasure,
confidence, and power
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Reality
– large doses of alcohol result in negative moods and
focus on problems and anxieties
– Alcohol impairs motor processes, information
processing, mood, sexual performance
– Learned beliefs about intoxication influence behavior
Addiction Has Psychological
and Physical Aspects
Addiction
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a physiological state in which failing to ingest a substance leads to
symptoms of withdrawal, a state characterized by anxiety, tension, and
craving
Physical dependence
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associated with tolerance, so that a person needs to consume more of
the substance to achieve the same subjective effect
Psychological dependence
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habitual and compulsive engagement despite the consequences
people can be psychologically dependent without showing tolerance or
withdrawal
individuals can be psychologically dependent on behaviors like
gambling, shopping, exercising, or internet use