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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Levels of Consciousness
Conscious Level
Directed Consciousness
Heightens sensations
Improves memory
Flowing Consciousness
Preconscious Level
Sensations, thoughts, etc., that ppl are not consciously aware of, but
which they can easily access
Unconscious Level
Described by Freud – sexual and aggressive impulses, as well as
other unacceptable thoughts/feelings/memories
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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 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.
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The Study of Sleep
• 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
• 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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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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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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