Transcript Body Rhythms and Mental States

Body Rhythms and Mental States
Chapter 5
Body Rhythms and Mental States
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Biological rhythms: The tides of experience
The rhythms of sleep
Exploring the dream world
Consciousness-altering drugs
The riddle of hypnosis
Biological Rhythms: Tides of Experience
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Understanding biological rhythms
Endogenous biological rhythms
Circadian rhythms
When internal clocks are out of sync
Moods and long-term rhythms
Menstrual cycles and moods
Understanding Biological Rhythms
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Consciousness
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Biological rhythms
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Awareness of oneself and the environment.
A periodic, more or less regular fluctuation in a
biological system; may or may not have psychological
implications.
Entrainment
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Biological rhythms are synchronized with external
events such as changes in clock time, temperature, and
daylight.
Endogenous Biological Rhythms
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Circadian Rhythms
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Infradian Rhythms
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Occur about every 24 hours.
Example:The sleep-wake cycle.
Occur less often than once a day.
Examples include birds migrating, bears hibernating.
Ultradian Rhythms
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Occur more frequently than once a day, about every 90min.
Examples include stomach contractions and hormone levels.
Circadian Rhythms
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Occur in plants, animals, insects and people.
To study endogenous circadian rhythms,
scientists isolate volunteers from time cues.
Supraciasmatic nucleus (SCN)
 Located in the hypothalamus, responsible for
circadian rhythms by regulating melatonin, a
hormone secreted by the pineal gland.
When Internal Clocks are Out of Sync
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Internal desynchronization
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A state when biological rhythms are not in
phase with one another.
Circadian rhythms are influenced by changes
in routine. Examples include:
Airplane flights across time zones.
 Adjusting to new work shifts.
 Also, illness, stress, fatigue, excitement, drugs,
and mealtimes.
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Moods and Long-term Rhythms.
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Seasonal Affective Disorder (SAD)
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A controversial disorder in which person
experiences depression during the winter and
an improvement of mood in the spring.
Treatment involves phototherapy or exposure
to fluorescent light.
Evaluating frequency of and treatment for
SAD is difficult.
Menstrual Cycles and Mood
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Physical symptoms are common.
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Cramps, breast tenderness and water
retention.
Emotional symptoms are rare.
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Irritability and depression.
Fewer than 5% of women have symptoms
predictably.
Why women overestimate “PMS”
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They notice depression or irritability when these
moods occur premenstrually but overlook times
when moods are absent premenstrually.
The attribute irritability before menstruation to
PMS and attribute irritability at other times to
other reasons.
They are influenced by cultural attitudes and
myths about menstruation.
Research conclusions about “PMS”
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No gender differences exist
in mood.
There is no relation
between stage of menstrual
cycle and emotional
symptoms.
No consistent “PMS”
pattern exists across
menstrual cycles.
The Rhythms of Sleep
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Why we sleep
When we don’t get enough sleep
The realms of sleep
Why We Sleep
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The exact function of sleep is uncertain but
sleep appears to provide time for:
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the body to eliminate waste products from
muscles,
repair cells,
strengthen the immune system, or
recover abilities lost during the day.
Sleep Disorders
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Sleep deprivation leads to decreases in physical
and mental functioning.
Sleep apnea
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Narcolepsy
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Breathing briefly stops during sleep, causing the person
to choke and gasp and momentarily waken.
A sleep disorder involving sudden and unpredictable
daytime attacks of sleepiness or lapses into REM sleep.
Staying up late and not allowing oneself enough
sleep
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2/3 of North Americans get fewer than recommended 8
hours
Realms of Sleep
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Stage 1. Feel self drifting on
the edge of consciousness.
Stage 2. Minor noises won’t
disturb you.
Stage 3. Breathing and
pulse have slowed down.
Stage 4. Deep sleep.
REM. Increased eye
movement, loss of muscle
tone and dreaming.
A typical night’s sleep for a young adult
Exploring the Dream World
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Dreams as unconscious wishes
Dreams as reflections of current concerns
Dreams as a by-product of mental
housekeeping
Dreams as interpreted brain activity
Dreams as Unconscious Wishes
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Freud concluded that dreams provide insight into
our unconscious.
Manifest content includes aspects of the dream
we consciously experience and latent content
includes unconscious wishes and thoughts
symbolized in the dream.
To understand a dream we must distinguish
manifest content from latent content.
Not everything in dream is symbolic.
Dreams as Reflections of Current
Concerns
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Dreams may reflect ongoing conscious issues
such as concerns over relationships, work, sex or
health.
Dreams are more likely to contain material
related to a person’s current concerns than chance
would predict.
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Example: university students and testing
Males and females appear to dream about similar
issues now that lives and concerns of two sexes
have become more similar.
Dreams as By-product of Mental
Housekeeping
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Unnecessary neural connections
in the brain are eliminated and
important ones are strengthened.
The brain divides new
information into “wanted” and
“unwanted.”
What we recall as dreams are only
brief snippets from scanning and
sorting that occurs during REM
sleep.
Dreams as Interpreted Brain Activity
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Activation-synthesis theory
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Dreaming results from the cortical synthesis
and interpretation of neural signals triggered
by activity in the lower part of the brain.
At same time, brain regions that handle
logical thought and sensation from the
external world shut down.
Consciousness-altering Drugs
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Classifying drugs
The physiology of drug effects
The psychology of drug effects
Classifying Drugs
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Psychoactive drug
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Substance capable of influencing perception, mood,
cognition, or behaviour.
Types
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Stimulants
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Depressants
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slow down activity in the CNS.
Opiates
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speed up activity in the CNS.
relieve pain.
Psychedelic drugs
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disrupt normal thought processes.
The Physiology of Drug Effects
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Psychoactive drugs work by acting on brain
neurotransmitters. These drugs can:
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increase or decrease the release of
neurotransmitters,
prevent reabsorption of excess neurotransmitters by
the cells that have released them,
block the effects of neurotransmitters on receiving
cells, or
bind to receptors that would ordinarily be triggered
by a neurotransmitter or a neuromodulator.
Cocaine’s Effect on the Brain
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Cocaine blocks the brain’s
reabsorption (“reuptake”) of the
neurotransmitters dopamine and
norepinephrine, so levels of
these substances rise.
The result is an overstimulation
of certain brain circuits and a
brief euphoric high.
When drug wears off, depletion
of dopamine may cause user to
“crash.”
The Psychology of Drug Effects
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Reactions to psychoactive drugs depend on:
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Physical factors such as body weight, metabolism,
initial state of emotional arousal and physical
tolerance.
Experience or the number of times a person has used a
drug.
Environmental factors such as where and with whom
one is drinking.
Mental set or expectations for drug’s effects.
The Riddle of Hypnosis
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Defining hypnosis
The nature of hypnosis
Theories of hypnosis
Defining hypnosis
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A procedure in which the practitioner suggests
changes in the sensations, perceptions, thoughts,
feelings or behaviour of the subject.
The Nature of Hypnosis
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The hypnotic state is not sleep.
Hypnotic responsiveness depends more on the
person being hypnotized than on the skill of the
hypnotist.
Hypnotized people can’t be forced to do things
against their will.
Feats performed under hypnosis can be performed
by motivated people without hypnosis.
The Nature of Hypnosis
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Hypnosis doesn’t increase accuracy of memory.
Hypnosis doesn’t produce a literal re-experiencing
of long-ago events.
Hypnotic suggestions have been used effectively for
medical and psychological purposes.
Theories of Hypnosis
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Dissociation theories
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Hypnosis is a split in consciousness in which one part
of the mind operates independently of the rest of the
consciousness, or
During hypnosis, dissociation occurs between an
executive control system in the brain (probably
frontal lobes) and other brain systems involved in
thinking and acting.
Theories of Hypnosis
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Sociocognitive theories
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Effects of hypnosis result from interaction between
social influence of the hypnotist (socio) and the
abilities, beliefs and expectations of the subject
(cognitive).
Can explain “alien abduction” and “past-life
regression.