19
3.
Altered states of consciousness
Consciousness
also has various modes, called
altered states of
consciousness.
Altered state can be induced by drastically decreasing a
subject’s sensory input, by exposing a subject to a highly repetitive and
boring sensory environment, by focusing a subject’s attention, by bom-
barding a subject with intense sensory inputs, or by administering mind-
altering drugs.
Altered states of consciousness share the following characteristics:
1.
Shallow (one dimensional) mental processing.
2.
Change in the way the self is experienced.
3.
Loss of normal inhibitions.
4.
Disconnection of perceptions from reality.
5.
Increase in vividness (brightness) of the contents of consciousness.
There are several modes of consciousness:
sleep, hypnosis, medita-
tion, biofeedback, altered states of consciousness caused by alcohol,
stimulants, marijuana, and hallucinogens etc.
Sleep
,
one mode of consciousness, is composed of several cyclical
90 – minute cycles of four stages, each with a characteristic brain wave
pattern.
Dreams occur during the REM (rapid eye movement).
Although
we clearly need REM sleep, the function of dreaming has not yet been
established. According to one’s mind, specific neural circuits associated
with the reticular formation, control sleep.
Sleep research is usually conducted by connecting subjects to an
EEG (electroencephalograph) and recording their brain waves as they
drift into sleep. Different types of brain waves are typically recorded at
different stages of sleep.
Beta waves
(14+ cycles per second) are fastest
and are typical in a fully awake person.
Alpha waves
(8-13
cycles per
second) are characteristic of relaxation. As a person falls asleep,
theta
waves
(5-7 cycles per second) also become evident. As sleep becomes
deeper,
delta waves
(4 or fewer cycles per second) become predominant.
There are four stages of sleep labeled 1,2,3 and 4, each progressive-
ly deeper. Delta sleep has been associated with restoration of the skeletal
muscles or the sensory system involved in controlling them. Although
stage 4 is characterized by deep relaxation, this is the stage (along with
stage 3) during which most episodes of sleepwalking, sleep talking, and
intense nightmares occur. In a typical night’s sleep,
you progress from
stage 1 to stage 4, and back to stage 1, about every 90 minutes.
20
At this time, you are likely to enter REM (Rapid Eye Movement)
sleep, the stage of sleep associated with dreaming. You dream about
four or five times each night. REM sleep differs greatly from non-REM
sleep. The scanning hypothesis speculates that the eye movements in
REM are due to the dreamer’s watching the dream’s activity.
REM sleep is paradoxical in that it appears
to be both a lighter
stage of sleep (as indicated by EEGs and physiological measures) and a
deeper stage of sleep (as evidenced by lack of muscle tone). If subjects
are deprived of REM sleep, they will spend more time in REM sleep on
the following night – the REM rebound. Several hypotheses have been
proposed to explain the possible value of REM sleep. Perhaps it is the
time the brain adapts to disturbing life events, since people need less
REM sleep,
as they grow older, (newborns spend about 50 percent of
their sleep in REM; old people, less than 5 percent). Perhaps REM sleep
plays a role in consolidating information into long term memory. Final-
ly, REM sleep may provide a means of reducing built-up energy when
our biological needs go unmet.
Sigmund Freud believed that dreams have two levels of meaning:
the manifest content is the story the dreamer remembers;
the latent
content is the deeper, underlying meaning of the dream, which can be
analyzed to reveal unconscious psychosexual conflicts. Most
psychologists who use dream analysis
favor interpretation of the
dream’s direct meaning (manifest content). Some psychologists are
working to develop “dream management” techniques, which will allow
subjects to control their dreams. Stephen La Berge, for instance, has
tried to increase his lucid dreams - dreams
in which he realizes he is
dreaming – as a means of reducing nighttime conflicts.
The most common sleep disorder is
insomnia,
the inability to stay
asleep or difficulty going to sleep.
Sleep apnea
Do'stlaringiz bilan baham: 
