Chapter 4 “States of Consciousness”
What is Consciousness?
● Consciousness is the awareness of self and environment, awareness of internal & external
motivations, and exists as a continuum.
What is sleep?
● Sleep is a natural and periodic state of unconsciousness. Physical activity is low during
sleep, and sensory awareness is reduced, unlike resting while awake. It's important to
note that being asleep differs from being "dead to the world."
Sleep and Wakefulness
Wakefulness
● High levels of sensory awareness, thought, & behavior
"Between the two extremes of sleep & wakefulness"
● Daydreaming, Intoxication, Meditative states, Hypnotic states, and Altered states
after sleep deprivation
Biological Rhythms
● Biological rhythms are the natural cycles of physiological and behavioral processes in
living organisms. Internal biological clocks drive these rhythms and can be influenced by
external factors like light, temperature, and social cues.
Biological rhythms: over varying periods, bodies fluctuate
• 24-hour biological clock
• 90-minute sleep cycle
Circadian rhythm
, • Internal biological clock of the 24-hour cycle of day and night (As morning approaches, body
temperature rises, peaks during the day, dips in the early afternoon, and begins to drop in the
evening. Alertness is associated with higher body temperature).
20 years old/ night owls Older adults/ morning larks
Circadian Rhythms
The suprachiasmatic nucleus (SCN): the brain’s clock mechanism located in the hypothalamus
● Neurons in retinas provide info to SCN based on the amount of light present, allowing the
internal clock to be synchronized w/the outside world
● Melatonin: a hormone that regulates sleep-wake cycles. Stimulated by darkness &
inhibited by light. Released by the pineal gland.
Disrupters of Sleep: People today sleep less than those who lived a century ago(many get less
than 7-8 hours). 31% get fewer than 6 hours a night—69% report insufficient sleep.
Electronics and Sleep
● Electronics emit blue light, which inhibits the release of melatonin, which leads to a
hard time falling asleep, less REM sleep, and waking up sleepier and less awake
Sleep Deprivation
● Has significant negative psychological & physiological consequences
Sleep Deprivation Effects
Sleep Deprivation Adequate Sleep
• Depression • Strengthens memory
• Relationship conflict • Increases concentration
• Obesity • Boosts mood
What is Consciousness?
● Consciousness is the awareness of self and environment, awareness of internal & external
motivations, and exists as a continuum.
What is sleep?
● Sleep is a natural and periodic state of unconsciousness. Physical activity is low during
sleep, and sensory awareness is reduced, unlike resting while awake. It's important to
note that being asleep differs from being "dead to the world."
Sleep and Wakefulness
Wakefulness
● High levels of sensory awareness, thought, & behavior
"Between the two extremes of sleep & wakefulness"
● Daydreaming, Intoxication, Meditative states, Hypnotic states, and Altered states
after sleep deprivation
Biological Rhythms
● Biological rhythms are the natural cycles of physiological and behavioral processes in
living organisms. Internal biological clocks drive these rhythms and can be influenced by
external factors like light, temperature, and social cues.
Biological rhythms: over varying periods, bodies fluctuate
• 24-hour biological clock
• 90-minute sleep cycle
Circadian rhythm
, • Internal biological clock of the 24-hour cycle of day and night (As morning approaches, body
temperature rises, peaks during the day, dips in the early afternoon, and begins to drop in the
evening. Alertness is associated with higher body temperature).
20 years old/ night owls Older adults/ morning larks
Circadian Rhythms
The suprachiasmatic nucleus (SCN): the brain’s clock mechanism located in the hypothalamus
● Neurons in retinas provide info to SCN based on the amount of light present, allowing the
internal clock to be synchronized w/the outside world
● Melatonin: a hormone that regulates sleep-wake cycles. Stimulated by darkness &
inhibited by light. Released by the pineal gland.
Disrupters of Sleep: People today sleep less than those who lived a century ago(many get less
than 7-8 hours). 31% get fewer than 6 hours a night—69% report insufficient sleep.
Electronics and Sleep
● Electronics emit blue light, which inhibits the release of melatonin, which leads to a
hard time falling asleep, less REM sleep, and waking up sleepier and less awake
Sleep Deprivation
● Has significant negative psychological & physiological consequences
Sleep Deprivation Effects
Sleep Deprivation Adequate Sleep
• Depression • Strengthens memory
• Relationship conflict • Increases concentration
• Obesity • Boosts mood
