Chapter 4
4th Edition
States of
Consciousness
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4-1
What Is Consciousness
• Consciousness is personal awareness of
feelings, sensations, and thoughts.
• Changes from normal consciousness are
known as altered states of consciousness.
• One common change in consciousness is
daydreaming.
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The Rhythms of Life
• A number of biological processes follow
regular rhythms or cycles that vary in
length.
• The study of biological rhythms,
chronobiology, includes research on the
effects of such cycles on the diagnosis
and treatment of diseases.
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The Rhythms of Life
• Circadian rhythms are
biological changes
that occur on a daily
schedule, including
the sleep-wake cycle
and the body
temperature cycle.
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The Rhythms of Life
• Circadian rhythms are controlled by the
suprachiasmatic nucleus (SCN) which is
located in the hypothalamus and acts as
an internal clock.
• Levels of a hormone secreted by the
pineal gland, melatonin, are affected by
light and darkness; thus melatonin may
play a role in controlling biological
rhythms.
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The Rhythms of Life
• By isolating volunteers in an environment
without time cues, researchers have found
the free-running sleep-wake cycle extends
to about 25 hours.
• To correspond to the 24-hour day, the
cycle must be reset every day by external
cues, especially sunlight.
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The Rhythms of Life
• Jet travel and shift work can disrupt the
sleep-wake cycle.
• The symptoms of Jet leg result from the
difference between our internal clock and
the time in our environment.
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The Rhythms of Life
• It is easier to adapt to phase delays (eastwest travel) than to phase advances
(west-east travel).
• Rotating shifts can be improved by using a
clockwise rotation (days to evenings to
nights), which involves a series of phase
delays.
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The Study of Sleep
• The major breakthrough in the study of
sleep was the observation of rapid eye
movements (REM).
• Measures of physiological processes such
as the electroencephalograph (EEG) also
aid sleep research.
• A sleep cycle lasts approximately 90
minutes and starts with non-REM (NREM)
sleep.
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The Study of Sleep
• We descend through
NREM Stages I to 4
and then ascend
through them to rapid
eye movement (REM)
sleep.
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The Study of Sleep
• The average adult repeats this cycle about four
to six times each night.
• Sleep decreases from about 16 hours at birth to
about 7 to 8 hours in young adulthood, with little
change thereafter.
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The Study of Sleep
• Observations of sleeping people suggest
that many people are not getting enough
sleep.
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The Study of Sleep
• Sleep efficiency (time in
bed actually asleep) is
lower among elderly
people, who experience
less slow-wave sleep and
spend increased time in
the lighter stages of
sleep.
• Naps are more common
than many people
believe.
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The Study of Sleep
• Sleep-deprived persons experience
microsleeps, which can cause poor
performance on tasks requiring attention.
• REM sleep deprivation leads to the REM
rebound, an increase in the amount of
REM sleep.
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The Study of Sleep
• Infants spend about 50%
of their sleep in REM,
perhaps to provide
stimulation needed for
brain development.
• Sleep may have evolved
to fill time, but the amount
of sleep in each species
depends on vulnerability
to predators and the need
to find food.
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The Study of Sleep
• Most cases of insomnia are of short
duration.
• Sleeping pills have limited usefulness and
should be used with care.
• The stimulus control method is an effective
treatment for sleep onset insomnia.
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The Study of Sleep
• Hypersomnias are sleep disorders marked by
excessive daytime sleepiness.
• Narcolepsy is characterized by daytime
sleepiness, cataplexy, and other symptoms
consistent with the intrusion of REM sleep into
waking hours.
• Overweight, middle-aged men are susceptible to
sleep apnea, which consists of frequent pauses
in breathing during the night.
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The Study of Sleep
• Parasomnias are sleep disturbances other
than insomnia and hypersomnias.
• Enuresis (bedwetting) is a common
disorder in childhood that can be treated
with the urine alarm.
• Sleepwalking and sleep terrors are
associated with Stage 4 sleep, tend to
occur in children, and usually disappear
without treatment.
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4-19
The Study of Sleep
• REM sleep behavior disorder occurs in older
men and consists of aggressive actions during
REM sleep.
• Nightmares are bad dreams that occur during
REM sleep.
• Sudden Infant death syndrome (SIDS) is the
leading cause of death among infants between 1
month and 1 year of age.
• Placing infants to sleep on the back may reduce
the incidence of SIDS.
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The Study of Sleep
• As typically defined, dreams are
associated with REM sleep, although N
REM sleep is not a mental void.
• Freud suggested that dreams serve to
fulfill sexual and aggressive wishes and
that we forget dreams due to repression.
• Analysis of the manifest content of a
dream yields the dream's latent content, or
supposed true meaning.
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The Study of Sleep
• Research has not supported Freud's views on
dreams.
• For example, forgetting dreams seems better
explained by waking activities that can interfere
with recall of dreams than by repression.
• Dreams often reflect cultural characteristics such
as a focus on relationships and levels of
aggression in a culture.
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The Study of Sleep
• The activation-synthesis hypothesis
suggests that dreams result from attempts
by the brain to make sense of high levels
of neuronal activity.
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Altering Consciousness With Drugs
• Psychoactive
substances are drugs
that affect
consciousness,
perception, mood,
and behavior.
• Regular and
excessive use can
lead to substance
abuse or substance
dependence.
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Altering Consciousness With Drugs
• Alcohol use is associated with a range of
medical and psychological consequences.
• One major effect is on parts of the brain
responsible for inhibiting behavior.
• The effects of alcohol are related to blood
alcohol concentration (BAC), an indication of the
amount of alcohol in the blood.
• Your BAC is determined by how much you drink,
the time you take to drink it, your weight, and
whether you have consumed food before or
while drinking.
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Altering Consciousness With Drugs
• Expectations about the effects of alcohol
can influence drinking patterns.
• The relation of alcohol to violence,
however, seems to be due to its biological
effects, not to expectations.
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Altering Consciousness With Drugs
• The rate of alcohol
abuse and
dependence is higher
in men than in
women.
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Altering Consciousness With Drugs
• Like alcohol, barbiturates and
benzodiazepines are depressants that
slow the activity of the central nervous
system.
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Altering Consciousness With Drugs
• Stimulants such as amphetamines speed up the
activity of the nervous system.
• One of the most widely used stimulants is
caffeine, which is found in foods such as
chocolate and beverages such as coffee.
• Nicotine, a major component of tobacco smoke,
is associated with preventable diseases such as
heart disease.
• Cocaine can get to the brain quickly and cause a
powerful high followed by a dramatic low.
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Altering Consciousness With Drugs
• Opiates, such as morphine and codeine,
are derived from the seedpod of the poppy
plant; their primary medical use is to
reduce pain.
• Heroin is a semi-synthetic compound
derived from morphine.
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Altering Consciousness With Drugs
• Hallucinogens can cause changes in
perception, including hallucinations.
• Among the best-known hallucinogens are
lysergic acid diethylamide (LSD) and
phencyclidine piperidine (PCP).
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Altering Consciousness With Drugs
• Marijuana consists of dried leaves and
flowers from the Cannabis sativa plant.
• The active psychoactive ingredient in
marijuana is delta-9-tetrahydrocannabinol
(THC).
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Altering Consciousness With Drugs
• MDMA or ecstasy is one of the designer drugs
that is manufactured from readily available
ingredients.
• There is growing evidence that MDMA can have
dramatic effects on memory and attention.
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Hypnosis
• Hypnosis, a heightened state of suggestibility,
can be traced to the 18th century, when Franz
Anton Mesmer claimed he had the power to
induce magnetic equilibrium in the bodies of his
patients.
• In contrast to the popular view that hypnosis is
an altered state of consciousness, evidence
suggests it does not differ from a state of
relaxation.
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Hypnosis
• Hypnosis has been used to reduce pain in
various kinds of medical treatments.
• It is not clear, however, what aspect of
hypnosis may be responsible for pain
reduction; relaxation, distraction, and
expectations seem to play significant
roles.
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Hypnosis
• Hypnosis has been used to improve recall.
• However, hypnotically refreshed memories
tend to contain distortions and false
reports.
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Hypnosis
• In hypnotic age regression, a hypnotized
person appears to return to childhood or
perhaps even to past lives.
• Research indicates age regression results
in the reporting of fantasies or memories
suggested by the hypnotist.
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Hypnosis
• The cognitive-social explanation suggests that
the observed phenomena can be explained by
the relationship between the hypnotist and the
hypnotized person, as well as by widely shared
expectations about the procedure.
• Another explanation, offered by Ernest Hilgard,
suggests that dissociation, or a splitting of
consciousness, may be at work in hypnosis.
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