Transcript Body Rhythms and Mental States

Body Rhythms and
Mental States
Chapter 5
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Chapter Outline
• Biological rhythms: The tides of
experience
• The rhythms of sleep
• Exploring the dream world
• Consciousness-altering drugs
• The riddle of hypnosis
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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
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Understanding Biological Rhythms
• Consciousness
– Awareness of oneself and the environment.
• Biological rhythms
– A periodic, more or less regular fluctuation in a
biological system; may or may not have
psychological implications
• Entrainment
– Biological rhythms are synchronized with external
events such as changes in clock time, temperature,
and daylight
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Endogenous Biological Rhythms
• Circadian Rhythms
– Occur about every 24 hours
– Example: The sleep-wake cycle
• Infradian Rhythms
– Occur less often than once a day
– Examples include birds migrating, bears hibernating
• Ultradian Rhythms
– Occur more frequently than once a day, about every
90min
– Examples include stomach contractions and hormone
levels
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Circadian Rhythms
• Occur in plants, animals, and people
• To study endogenous circadian rhythms,
scientists isolate volunteers from time cues
• Suprachiasmatic nucleus (SCN)
– Located in the hypothalamus, responsible
for circadian rhythms by regulating
melatonin, a hormone secreted by the
pineal gland
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When Internal Clocks are
Out of Sync
• Internal desynchronization
– 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
• Seasonal Affective Disorder (SAD)
– 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
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Menstrual Cycles and Mood
• Physical symptoms are common
– Cramps, breast tenderness and water
retention
• Emotional symptoms are rare
– Irritability and depression
– Fewer than 5% of women have symptoms
predictably
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Why Women Overestimate “PMS”
• They notice depression or irritability when
these moods occur premenstrually but
overlook times when moods are absent
premenstrually
• They 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
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Research Conclusions about “PMS”
• 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
• No connection exists
between “PMS” and
behaviour
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The Rhythms of Sleep
• Why we sleep
• Sleep deprivation & disorders
• The realms of sleep
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Why We Sleep
• The exact function of sleep is uncertain
but sleep appears to provide time for:
– the body to eliminate waste products from
muscles
– repair cells
– strengthen the immune system, and
– recover abilities lost during the day
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Sleep Deprivation & Disorders
• Sleep deprivation leads to decreases in
physical and mental functioning.
• Sleep apnea
– Breathing briefly stops during sleep, causing the
person to choke and gasp and momentarily waken.
• Narcolepsy
– 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
– 2/3 of North Americans get fewer than
recommended 8 hours
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Realms of Sleep
• 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
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A Typical Night’s Sleep for
a Young Adult
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Exploring the Dream World
• Dreams as unconscious wishes
• Dreams as efforts to deal with
problems
• Dreams as a by-product of mental
housekeeping
• Dreams as thinking
• Dreams as interpreted brain activity
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Dreams as Unconscious Wishes
• 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 dreams is symbolic
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Dreams as Efforts
to deal with Problems
• 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
– Example: college students and testing
• Males and females appear to dream about
similar issues now that lives and concerns of
two sexes have become more similar
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Dreams as By-product of Mental
Housekeeping
• 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
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Dreams as Thinking
• Dreams are a modification of the
cognitive activity that goes on when we
are awake
• Difference between wakefulness and
dreaming is that we are cut off from
sensory input and bodily feedback
during dreaming
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Dreams as Interpreted Brain Activity
• Activation-synthesis theory
– 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
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Activations Synthesis Theory
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Consciousness-altering Drugs
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Classifying drugs
The physiology of drug effects
The psychology of drug effects
The drug debate
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Classifying Drugs
• Psychoactive drug
– Substance capable of influencing perception,
mood, cognition, or behaviour
– Types
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Stimulants speed up activity in the CNS
Depressants slow down activity in the CNS
Opiates relieve pain
Psychedelic drugs disrupt normal thought
processes
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The Physiology of Drug Effects
• Psychoactive drugs work by acting on brain
neurotransmitters. These drugs can:
– 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
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Cocaine’s Effect on the Brain
• Cocaine blocks the brain’s
reabsorption (“reuptake”) of
the neurotransmitters
dopamine and
norepinephrine, so levels of
these substances rise
– Results in an overstimulation
of certain brain circuits and a
brief euphoric high
– When drug wears off,
depletion of dopamine may
cause user to “crash”
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The Psychology of Drug Effects
• Reactions to psychoactive drugs depend on:
– 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
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The Drug Debate
• Can we distinguish between use and abuse?
• Many ‘legal’ drugs are highly consumed
e.g., coffee, tobacco, alcohol
• Many ‘illegal’ drugs reportedly have positive
or medical uses
• Canadians debate over marijuana use and
benefits as well as “safe-injection sites” for
heroin, cocaine and other IV drugs
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The Riddle of Hypnosis
• Defining hypnosis
• The nature of hypnosis
• Theories of hypnosis
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Defining hypnosis
• A procedure in which the practitioner
suggests changes in the sensations,
perceptions, thoughts, feelings or
behaviour of the subject
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The Nature of Hypnosis
• 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
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The Nature of Hypnosis
• Hypnosis doesn’t increase accuracy of
memory
• Hypnosis doesn’t produce a literal reexperiencing of long-ago events
• Hypnotic suggestions have been used
effectively for medical and psychological
purposes
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Theories of Hypnosis
• Dissociation theories
– 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
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Theories of Hypnosis
• Sociocognitive theories
– 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
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