PSYC 1020H Chapter Notes - Chapter 5: Circadian Rhythm, Mind-Wandering, Jet Lag
14 Jun 2018
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Psych 1020
Chapter 5: Variations in Consciousness
Oct 31, 2017
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Consciousness: the awareness of internal and external stimuli
- William James emphasized that consciousness is a continually changing stream of mental
activity, and varies along a continuum of levels of awareness
- Controlled processes are those over which we have intentional control, automatic
processes occur without intention
Variations in Awareness and Control
- Attention and consciousness are closely related: while some things that enter our
consciousness are intentional, other thoughts and minds seem to wander: this is called
Mind Wandering: peoples epeiee of task- unrelated thoughts
- It is estimated that people spend 15 to 20% of their time mind wandering
- The difference between what we control about our mental processes and what just
seems to happen is referred to as controlled and automatic processes
Theory of Unconscious Thought: Ap Dijksterhuis
- In some circumstances, not engaging in conscious thought may help make more accurate
decisions
- Conscious thought is constrained by capacity limitations (you only consider a subset of all
relevant info) where as unconscious thought does not have the same capacity constraints
- Cosious thought is thought ith attetio; uosious thought is thought ithout
attention or with attention directed elsewhere
Consciousness and Brain Activity
- Consciousness arises from activity in distributed networks of neural pathways
- Most commonly used indicator of variations in consciousness has been the EEG
(Electroencephalograph): a device that monitors the electrical activity of the brain over
time by means of recording electrodes attached to the surface of the scalp. It
summarizes the rhythm of cortical activity in terms of brain waves, which are divided into
bands based on the frequency of the brain waves
- Changes in EEG activity are closely related to variations in consciousness: (not causation)
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2
EEG Pattern
Frequency (cps)
Typical States of
Consciousness
Beta
13-24
Normal waking thought,
alert problem solving
Alpha
8-12
Deep relaxation, blank
mind, meditation
Theta
4-7
Light sleep
Delta
Less than 4
Deep sleep
Biological Rhythms and Sleep
- Biological rhythms are periodic fluctuations in physiological functioning: existence means
we have internal biological clocks that monitor the passage of time
The Role of Circadian Rhythms
- Circadian rhythms are the 24-hour biological cycles found in humans and many other
species.
o influential in the regulation of sleep
o daily cycles produce rhythmic variations in blood pressure, urine production,
hormonal secretions and other physical functions, as well as short term alertness
and memory and other cognitive processes
o can leave individuals physiologically primed to fall asleep most easily at a
particular time; people generally fall asleep as their body temp begins to drop and
awaken as it rises again
o exposure to light eadjusts peoples iologial loks: eeptos i etia sed
direct inputs to suprachiasmatic nucleus (SCN) which sends signals to the pineal
gland that then secretes melatonin
Ignoring your Circadian Rhythms
- If you get less sleep than the amount of sleep that you need, you accumulate sleep debt
which needs to be paid back with extra sleep
- Causes jet lag: speed of resetting varies from person to person and depends on direction
travelled
- Lack of sleep or poor-quality sleep a iease okes accident proneness, mental and
physical health, more stress and lower sense of mastery or control
Realigning them
- Research is now looking into giving people small doses of melatonin which regulates the
biological clock. Research however is inconsistent because the timing has to be optimal
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3
The Sleeping and Waking Cycle
- The evolutionary significance of sleep still has debate on its function as an adaptation; it
may have helped us conserve energy, reduce our exposure to predators, helps animal
restore bodily resources depleted by waking activities
- Researchers now conducting research on what happens when people sleep (the mental
and physical activity the body goes through)
- They use electromyograph (EMG) which records muscular activity and tension, and an
electrooculography (EOG) which records eye movements
Stages of Sleep
Stages 1-4
- The length of time it takes for people to fall asleep relies on a variety of factors: circadian
cycle, last time they slept, amount of noise or light in the environment, age, desire to fall
asleep, boredom level etc.
- Stage 1: a brief transitional stage of light sleep that usually lasts only a few minutes;
breathing and heart rate slow as muscle tension and body temp decline, hypnic jerks
occur (muscular contractions that occur as people fall asleep)
- Stage 2-4: cycle, respiration rate, heart rate, muscle tension and body temperature
- Stage 2 lasts between 10-25 mins. Gradually, brain waves become higher in amplitude
and slower in frequency, as the body moves into a deeper form of sleep called slow-wave
sleep (SWS): consists of sleep stages 3 and 4, during which high-amplitude, low-frequency
delta waves become prominent in EEG recordings
REM Sleep (Stage 5)
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Document Summary
Consciousness: the awareness of internal and external stimuli. William james emphasized that consciousness is a continually changing stream of mental activity, and varies along a continuum of levels of awareness. Controlled processes are those over which we have intentional control, automatic processes occur without intention. Attention and consciousness are closely related: while some things that enter our consciousness are intentional, other thoughts and minds seem to wander: this is called. Mind wandering: people(cid:859)s e(cid:454)pe(cid:396)ie(cid:374)(cid:272)e of task- unrelated thoughts. It is estimated that people spend 15 to 20% of their time mind wandering. The difference between what we control about our mental processes and what just seems to happen is referred to as controlled and automatic processes. In some circumstances, not engaging in conscious thought may help make more accurate decisions. Consciousness arises from activity in distributed networks of neural pathways.
