States of Consciousness
Consciousness is not necessarily a state that
is fully distinct from unconsciousness.
There are varying degrees of consciousness.
It is a very fascinating topic to contemplate and
discuss.
It is a very difficult topic to investigate.
“Its meaning we know so long as no one asks us
to define it.
”
Module 10.1
Consciousness
Consciousness: The subjective experience
of perceiving one’s self and other entities.
Brain activity and consciousness are
inextricably related. Decreases in brain activity typically accompany declines in level of consciousness.
Not all neurological activity is conscious
though, such as reflexes and other essential activities originating in the spinal cord.
Consciousness
It is unclear whether consciousness is
defined by a certain threshold of brain
activity or is an all-or-nothing phenomenon.
Brain activity below a certain level is
unconscious – therefore it is a threshold
that once crossed produces a distinct sense of awareness.
Consciousness
We have the impression that we construct
our consciousness as it happens.
It seems though that our awareness
actually lags behind their presentation by a few microseconds, even though we feel as if we’ve been aware of them the whole time.
Studies of the phi effect – suggest that later
occurring stimuli retroactively change our conscious perceptions of previous ones.
Unconscious Processes
Studies of spatial neglect and blindsight
provide evidence of unconscious processing.
Spatial neglect is a tendency of persons
who have right hemispheric damage to
ignore information and sensations affecting the left side of the body.
Blindsight is found in individuals who suffer
from cortical blindness. They respond to visual stimuli though they will report not being consciousness of them.
Unconscious Processes
The phenomenon of readiness potential –
the increased motor cortex activity prior to the start of a movement - provides evidence that we begin our actions before we become aware of our intention to act.
Other Phenomena of
Consciousness
Deja vu is feeling of uncanny familiarity
with a strange person, new place or event.
Capgras syndrome is a condition in which
person insists that familiar individuals are actually impostors who resemble those
people.
These continue to pose challenges as we
attempt to determine their neurological origins.
The Role of Consciousness
The level of consciousness (if any) of
non-human animals is still a mystery to us.
The functions of consciousness are no
longer considered impossible to study.
But it still presents daunting scientific
Module 10.2
Circadian Rhythms
Circadian rhythms are cycles of activity and
inactivity generally lasting about one day (from the Latin circa = “about” and dies = “day”.)
Most people’s circadian rhythms, when allowed
to occur in an environment free of familiar time cues (like living in a cave for several months) stabilize at a little over 24 hours.
Your degree of alertness depends where you
Circadian Rhythms
Are you are morning person, or an evening
person?
Human beings seem to fall on a continuum:
morning people, evening people, or no distinct preference.
Where you fall on the continuum seems to have
Circadian Rhythms
Are you are morning person, or an evening
person?
Most young adults are evening people, or
neutral.
Most people over the age of 65 are morning
people.
This difference is even found in performance
differences in laboratory rats (Winocur & Hasher, 1999.)
Figure 10.7
Figure 10.7: If tested early in the morning, older persons perform as well as younger people on memory tasks. As the day progresses, young people improve and older people
Circadian Rhythms
Shifting sleep schedules
Mechanisms in the brain rely on light to reset
your body’s clock and keep it in step with the environment.
If you travel between time zones you will be
out of step for a while.
Jet lag is the period of weariness and
discomfort that occurs while your body clock adjusts to your new time zone. It is easier to adjust going east to west than west to east.
Figure 10.8
Circadian Rhythms
Shifting sleep schedules
Staying up late on the weekends (if this is not
one’s usual habit) can produce a jet lag type feeling – “Monday morning brain fog.”
Shift work is also problematic. “Graveyard”
and “rotating” shifts are very difficult.
Being awake at times when the body is primed
for sleep is hazardous to health (due to lapses in judgment and slow reflexes).
Figure 10.9
Figure 10.9 The graveyard shift is aptly named. Serious industrial accidents usually occur at night, when workers are least alert. As in jet lag, the direction of change is critical. Moving forward—clockwise—is easier than going backward.
Circadian Rhythms
Shifting sleep schedules
Transferring rotating shift workers to later
shifts may be less stressful and harmful than transferring them to earlier shifts.
Providing bright lights on the night shift can
also ameliorate some of the harmful effects of being awake when the body clock is set for
Concept Check
If you are a Los Angeles–based CEO, and you
need meet with an executive from New Delhi,
India, to negotiate a tough deal, should you try
to convince the executive in Europe or in
Japan?
Japan
Circadian Rhythms
Brain mechanisms
The circadian cycle of sleep and wakeful states
is governed by the suprachiasmic nucleus (“SCN”.)
This tiny structure at the base of the brain is
essentially your body’s “clock.”
The SCN controls the sleep-wake cycle in part
by regulating the secretion of the hormone melatonin by the pineal gland.
Figure 10.10
Figure 10.10 The suprachiasmatic nucleus, a small area at the base of the brain, produces the circadian rhythm. Information from the optic nerves resets the circadian rhythm but is not necessary for its generation.
Why Do We Sleep?
Several benefits
Sleep saves energy
Mammals and birds lower their body temperature. Animals decrease muscle activity.
People conserve energy in times of famine by
sleeping longer and lowering their body temperature.
Why Do We Sleep?
Sleep helps restorative functions in the brain
Sleep deprivation leads to irritability, impaired
attention, and weakened immune system
But some people need less sleep than others
• Evolutionary theory: Animals have evolved to only sleep as much as is safe and doesn’t interfere with their needs (birds don’t sleep during migration)
– Lions sleep about 20 hours a day while gazelles sleep much less.
– Gazelles are on the menu for lions. They need more time to eat, and must run away quickly.
“The lion and the calf shall lie down together, but the calf won’t get much sleep.”
-- Woody Allen
Why Do We Sleep?
Sleep strengthens learning and memory.
Applies to motor skills and language-related
tasks
Areas in brain specialized for motor tasks are
active during sleep after learning new motor task
Figure 10.11
Figure 10.11 Predatory mammals sleep more than prey mammals. Predators are seldom attacked during their sleep, but prey species need to arouse quickly from sleep to avoid being attacked. (Based on data from Zepelin & Rechschaffen, 1974)
Stages of Sleep
The discovery of REM
Sleep research was jump-started in the late
1950’s when researchers in the United States and France independently discovered REM activity during sleep.
REM stands for rapid-eye movement because the
sleeper’s eyes are moving rapidly around under the closed eyelids.
Stages of Sleep
The discovery of REM
It is also referred to as paradoxical sleep because
there is physiological and brain wave activity almost indistinguishable from the waking state.
Yet the large muscles of the sleeper are so relaxed
Stages of Sleep
REM and dreaming
People tend to report vivid dreams when
awakened during REM sleep.
But complex dreams have also been reported
during non-REM sleep, especially the Stage II NREM sleep that occurs at the end of the
night.
Researchers are now questioning the close
Stages of Sleep
Sleep cycles during the night
Researchers use an electroencephalograph
(EEG), a machine that measures electrical activity on the scalp that is associated with
activity in the brain combined with a device to measure eye movements.
This combined machine is called a
polysomnograph.
It is used to track the changes in the sleeper’s
Stages of Sleep
NREM stages
When first dozing off, the sleeper enters Stage
1 NREM.
There is little eye movement, and a fair amount
of brain activity (“desynchronized” activity.)
Stage 2 NREM follows, in which a gradual
transition begins into the synchronized, slow wave states.
Stages of Sleep
NREM stages
Stages 3 and 4 NREM feature long, slow
synchronized waves.
These waves indicate decreased brain activity. The eyes remain relatively inactive during
these slow-wave stages.
The sleeper gradually moves back through
stages 3 and 2 and then has the first brief REM episode of the night.
Stages of Sleep
Pattern of stages across the night
This first episode of REM ends the first cycle of
the night.
A healthy adult has 90-100 minute sleep cycles
all during the night.
After the first cycle, REM replaces stage 1. Stages 3 and 4 decrease during the night.
The last sleep cycles of the night are usually
comprised of alternations between stage 2 and REM.
Stages of Sleep
Patterns of dreaming
Adults report dreams 85-90% (REM) and
50-60% (NREM) of the time on awakening.
Adults who claimed that they don’t dream
report dreams when awakened during REM in a sleep laboratory.
Children < 5 y.o. rarely report any dreams. Dreams follow REM in length – 1 minute of
REM produces a brief dream, longer periods produce more complex dream stories.
Concept Check
Are dream less likely to be reported towards
the beginning or the end of the night?
The beginning
There is proportionally less REM sleep and brain activity during the first four hours of the night.
Stages of Sleep
The functions of REM sleep
When people are deprived of only REM sleep,
their brains will produce more and more of it.
They will also become quite irritable, anxious
and distracted.
People deprived of REM sleep will experience a
Stages of Sleep
The functions of REM sleep
Over the life cycle, patterns of REM sleep
change.
Infants get more REM sleep than children, and
children get more than adults.
We infer from this that REM has some role in
Figure 10.16
Figure 10.16 Newborns’ sleep alternates between wakefulness and naps throughout the day. Within a few months, infants consolidate most of their sleep into one longer period at night, although they continue having one or two naps during the day. As people grow older, the amount of sleep per day decreases. (Based on Kleitman, 1963)
Stages of Sleep
The functions of REM sleep
Species that sleep more get more REM.
Humans who sleep 9 hours or more get more
REM sleep than those who sleep 6 hours or less.
New research suggests that REM sleep may
help to improve memory for difficult new tasks.
It may also help to improve memory for motor
Stages of Sleep
The functions of REM sleep
The original purpose of REM may not have
been to help storage of memories for complex tasks.
REM might have developed to help oxygenate
the corneas during sleep.
As computers were invented for mathematical
calculation, and became much more diverse, so REM may also have acquired more complex
Abnormalities of Sleep
Insomnia
Insomnia means “lack of sleep.” It is hard to
define insomnia by number of hours because there’s a wide range of normal sleep lengths.
Insomnia is better defined by complaints of
feeling poorly rested due to lack of sleep.
Many adults have occasional insomnia.
Serious or chronic insomnia is often associated
with medical or psychological disorders such as depression.
Abnormalities of Sleep
Sleep apnea
One possible cause of insomnia is sleep apnea. People with sleep apnea may fail to breathe for a
minute or longer, and wake up gasping for breath, or die.
Snoring is closely associated with this disorder. Many sufferers from sleep apnea are obese
middle-aged or elderly men.
Other cases of sleep apnea are associated with
Abnormalities of Sleep
Narcolepsy
Sudden attacks of extreme and irresistible
sleepiness during the day is known as narcolepsy.
Associated with these attacks are muscle
weakness or paralysis and vivid dreams.
It is as if they are having a sudden burst of
Abnormalities of Sleep
Parasomnias
Other unsettling occurrences during sleep
include:
Sleep talking, which is not a symptom of any
psychological disorder.
Sleep walking, usually found in children during
stage 4 sleep. It is perfectly safe to wake a sleepwalker.
Abnormalities of Sleep
Parasomnias
Other unsettling occurrences during sleep
include:
Nightmares, or unpleasant dreams that are
reported by almost everyone at some time.
Night terrors, which involve awaking during
slow-wave sleep in an extreme panic, more common in children than in adults.
Abnormalities of Sleep
Leg movements while trying to sleep
Prolonged “crawly” sensations, accompanied
by strong repetitive leg movements that wake the sleeper are part of a condition called
periodic limb movement disorder (“restless leg syndrome”).
These symptoms usually occur during the first
half of the night. Caffeine, stress and fatigue are thought to aggravate it.
Abnormalities of Sleep
Hypersomnia: Too much sleep?
Hypersomnia: excessive sleep that is not refreshing. Example: a person who gets over 8 hours a day
during the week, and then needs to “catch up” by getting over 15 hours per day on the weekend and still reports feeling groggy, confused, and poorly rested.
Otherwise there is no such thing as “too much
The Content of Our Dreams
It was once believed that dreams foretold the
future.
But we now are certain that this is only by
coincidence.
The major controversy in psychology is
whether or not the dream tells us anything
about the dreamer.
The Content of Our Dreams
Freud’s approach
Sigmund Freud, the founder of the
psychoanalytic school, maintained that dreams reveal the dreamer’s unconscious thoughts and motivations.
He referred to the surface content of the dream as
“manifest” content.
He called the hidden content, represented only in
The Content of Our Dreams
Freud’s approach
The only way an analyst can discover the
meaning of the latent content is to determine the dreamer’s personal associations to the
details of the manifest content.
This approach to dream analysis was very
popular for many years.
But it’s not scientific – there is no to be certain
what a dream means, or to test this approach empirically.
Concept Check
What would Sigmund Freud think of popular
books that purport to interpret any reader’s
dream symbols – what pens, cars, or handbags
mean to any dreamer?
Not much
He believed that you needed to know the dreamer’s associations to the content.
Theories of Dreaming
The Activation-Synthesis theory
This theory of dreams proposes that input from
the brainstem (the pons) activates the brain during REM sleep.
The cerebral cortex tries to make sense of the
random activity by imposing a story on the stimuli that activate the sense organs during this process.
Theories of Dreaming
The Activation-Synthesis theory
The meaning is not a cause, as in Freud’s
approach, but rather a by-product.
This theory does not make clear, testable
Theories of Dreaming
The Neurocognitive theory
This theory assumes that dreaming is thinking,
occurring under special conditions.
The conditions include: persistent activity of
the cortex, reduction of sensory stimulation, and loss of self-control of thinking.
REM is not necessary for dreaming, but the
emotional arousal created by REM tends to intensify dreams.
Theories of Dreaming
The Neurocognitive theory: Evidence
Dreaming seems to require some degree of
cognitive maturity (dreams are rarely reported by children under 5.)
The stronger the imagination of the person
when awake, the greater the chance of dreaming.
There are common “dream themes” in the
United States; usually these are concerned with anxiety and things going wrong.
Table 10.2
Sleep
Sleep research has allowed our scientific
knowledge of consciousness to grow. Many
interesting questions remain about the nature
of sleep and the function of its stages,
especially REM and the phenomenon of
dreaming.
Module 10.3
Hypnosis
What is hypnosis?
Hypnosis (from the word “Hypnos,” the name
of the Greek God of sleep) is a condition of increased suggestibility that occurs in the context of a special hypnotist-subject
relationship.
But it is not the same as sleep. Hypnotized
people can respond to stimuli from the outside world.
Hypnosis
What is hypnosis?
Hypnosis was first practiced by an Austrian
philosopher and physician, Franz Anton Mesmer.
He attributed his success at various treatment
strategies (use of magnets and his own hands) as evidence of his own “animal magnetism.”
In all likelihood, his subjects were responding
Hypnosis
Ways of inducing hypnosis
Hypnosis is a voluntary, cooperative social
interaction
There are no special powers required to be a
hypnotist.
No one can hypnotize an uncooperative person. Believing that one is hypnotized is a big step
Hypnosis
Uses and limitations of hypnosis
Hypnosis can produce:
Increased relaxation Better concentration
Temporary changes in behavior that sometimes
persist beyond the end of the hypnotic state
It will NOT give a person new mental or
Hypnosis
Uses and limitations of hypnosis
A well-established use of hypnosis is to help a
person control and manage pain.
Some people can undergo dental or medical
procedures with hypnosis alone.
This is a very helpful ability for those who have
unfavorable reactions to anesthetic drugs or who have developed a tolerance to painkillers.
Hypnosis
Uses and limitation of hypnosis
Pain has both sensory and emotional
components.
For a hypnotized person, the emotional
reaction is altered. The sensory portions of the brain are stimulated, as is the case for a person who has not been hypnotized, but the
Figure 10.17
Figure 10.17 A hypnotic suggestion to experience less pain decreases activity in the frontal cortex areas associated with emotional distress but has little effect on the sensory areas in the parietal cortex.
Hypnosis
Uses and limitations of hypnosis
Another use of hypnosis is the posthypnotic
suggestion
A posthypnotic suggestion is a suggestion to do or
experience something particular after coming out of hypnosis.
Some treatments for addiction or bad habits that
use repeated applications of posthypnotic suggestion have shown modest to moderate success.
Hypnosis
Uses and limitations of hypnosis
Distortions of perception under hypnosis
A few people report that they experience
hallucinations under hypnosis, particularly haptic (touch) hallucinations.
The brain areas involved in sensory processing
were activated in some cases.
Hypnotized people who claim that they are NOT
registering actual stimuli will show activity in the brain areas that process those stimuli.
Hypnosis
Uses and limitations of hypnosis
Hypnosis cannot:
Give a person increased or special physical strength
- anyone can do the things that people under hypnosis have been able to do.
Enhance memory – people under hypnosis are
highly suggestible and memories “recovered” in this state are prone to be inaccurate and influenced by the hypnotist.
Hypnosis
Uses and limitations of hypnosis
Hypnosis increases confidence that recovered
memories are accurate.
Hypnotized people will perform some strange
and risky acts. Although the evidence is limited by the fact that it is hard to find things that
nonhypnotized people will refuse to do, it
appears to be the case that people will not do anything under hypnosis that they aren’t really willing to do.
Concept Check
What are some practical uses of hypnosis?
Pain management Relaxation
Hypnosis
Is hypnosis an altered state of consciousness?
The debate concerning hypnosis is whether it
is a special state of consciousness involving greatly increased suggestibility, or too similar to a normal waking state to be thought of as distinct from that state.
Most psychologists are currently taking a
Hypnosis
Is hypnosis an altered state of consciousness?
How well can an unhypnotized person pretend
to be hypnotized?
Unhypnotized people can mimic most of the effects
Hypnosis
Is hypnosis an altered state of consciousness?
Observers are able to distinguish between those
who have been hypnotized and those who are pretending.
It seems that effects that are mimicked by
pretenders happen spontaneously for hypnotized people.
Concept Check
Does hypnosis give people extraordinary or
unusual powers?
Hypnosis
Meditation: In some ways like hypnosis
Meditation is a method of inducing a calm,
relaxed state through the use of special techniques.
It is a tradition that has been practiced in many
world cultures for thousands of years.
It has some similarities to the relaxed, passive state
of hypnosis, but it requires no hypnotist or suggestions.
Hypnosis
Meditation: In some ways like hypnosis
Studies have documented that meditation can
decrease physiological arousal, thus it is useful for relaxation training.
As with hypnosis, it is important to try to separate
truth from exaggerated claims when considering meditation.
The Nature of Hypnosis
A general consensus has yet to be reached on
this topic, but agreement has been reached on certain points:
Hypnosis is not merely faking or pretending.
It does not bestow any unusual abilities or
powers.
It does enable people to relax, concentrate and
follow suggestions better than they otherwise would.
Beware of any person who claims that it can do
Consciousness
Altered states are not vastly different than
normal states of consciousness. Dreaming
appears to be a form of thinking and hypnosis
is a volitional state and produces only mild
effects.
