Notes From Reading
CHAPTER 5: VARIATIONS IN CONSCIOUSNESS
I. On The Nature of Consciousness
1. Consciousness is the awareness of internal and external stimuli and includes:
a.You’re awareness of external events
b. You’re awareness of internal sensations
c.You’re awareness of self as the unique being going through these experiences
d. Your awareness of your thoughts about these experiences
B. Variations in Levels of Awareness
1. Conscious and Unconscious are different levels of awareness.
C. The Evolutionary Roots of Consciousness
1. Consciousness may have allowed ancestors to think through courses of action and
their consequences, and then choose the best course, but no concrete answer.
D.Consciousness and Brain Activity
1. Electroencephalograph (EEG) – device that monitors the electrical activity of the
brain over time by means of recording electrodes attached to the surface of the scalp. i.e.
Summarizes the rhythm of activity of the brain (brain waves).
2. 4 Types of Brainwaves based on frequency – beta, alpha, theta, and delta
3. Variations in consciousness re correlated with variations in brain activity.
II. Biological Rhythms and Sleep
A.The Role of Circadian Rhythms
1. Biological rhythms are periodic fluctuations in physiological functioning. Implies
existence of “biological clocks”
2. Circadian rhythms are the 24 hour biological cycles found in humans and many other
3. When the retina is exposed to light, it sends direct inputs into the SCN – the central
pacemaker located in the hypothalamus
B. Ignoring Circadian Rhythms
1. Quality of Sleep Suffers
2. Fatigue, Sluggishness, and Irritability
3. Negative impact on productivity, accident proness, quality of work, social relations,
and physical and mental health.
C. Melatonin and Circadian Rhythms
1. Hormone Melatonin – regulates human bio clock. May be effective as a mild
sedative, to treat insomnia.
III. The Sleep and Waking Cycle
A.Conducting Sleep Research
1. Used to monitor Sleep:
a.Electromyograph (EMG) – records muscle activity and tension
b. Electrooculograph – records eye movements
B. Cycling Through the Stages of Sleep
1. Stages 1: a brief transitional stage of light sleep that lasts only a few minutes.
a.Breathing and heart rate slow, muscle tension and body temp go down.
b. Alpha Waves are replaced with theta waves.
c.Hypnic jerks may occur.