UNIT 2: Biological Bases of Behavior
PART II: States of Consciousness
Learning Targets
17-1 Describe the effects of sleep loss, and identify the major sleep disorders.
17-2 Describe the most common content of dreams, and identify the functions theorists have proposed for dreams.
Sleep loss
In a 2013 Gallup poll, 40 percent of
Americans reported getting
6 hours or less sleep a night.
(Jones, 2013).
What are some consequences �of sleep loss?
For students, less sleep predicts more conflicts in friendships and romantic relationships.
(Gordon & Chen, 2014; Tavernier & Willoughby, 2014)
Sleep loss is a predictor of depression.
(Baglioni et al., 2016)
Sleep deprivation increases appetite and eating; our tired brain finds fatty foods more enticing.
(Fang et al., 2015; Hanlon et al., 2015).
How does sleep loss impact �our physical health?
Sleep deprivation can suppress immune cells that battle viral infections and cancer.
(Möller-Levet et al., 2013; Motivala & Irwin, 2007; Opp & Krueger, 2015)
Those who averaged less than 5 hours’ sleep a night were 4.5 times more likely to develop a cold than those who slept more than 7 hours a night.
(Prather et al., 2015)
Older adults who have no difficulty falling or staying asleep tend to live longer than sleep-deprived agemates.
(Dew et al., 2003; Parthasarathy et al., 2015; Scullin & Bliwise, 2015)
Are you sleep deprived?
How did you do?
If you answered “true” to three or more items, you probably are not getting enough sleep.
To determine your sleep needs, one researcher recommends
“go to bed 15 minutes earlier than usual every night for the next week — and continue this practice by adding 15 more minutes each week — until you wake without an alarm clock and feel alert all day.”
Smartphones as sleep stealers:
“ You wake up in the middle of the night and grab your smartphone to check the time — it’s 3 a.m. — and see an alert.
Before you know it, you fall down a rabbit hole of email and Twitter. Sleep? Forget it.”
Nick Bilton, “Disruptions: For a
Restful Night, Make Your Smartphone
Sleep on the Couch,” 2014
How sleep deprivation impacts us.
Sleep loss and car accidents
On the Monday after the springtime change, when people lose one hour of sleep, accidents
increased, as compared with the Monday before.
Sleep gain and car accidents
In the fall, traffic
accidents normally increase because of greater snow, ice, and
darkness, but they diminished
after the time change.
(Data from Coren, 1996.)
1. What Would You Answer?
Sleep deprivation can lead to weight gain, reduced muscle strength, suppression of the cells that fight common colds, and most likely which of the following?
What are the most common �sleep-wake disorders?
What is insomnia?
About 1 in 10 adults, and 1 in 4 older adults, complain of
insomnia — persistent problems in either
falling or staying asleep
(Irwin et al., 2006).
The result is tiredness and increased risk of depression.
From middle age on, awakening occasionally during the night becomes the norm, not something to fret over or treat with medication.
(Vitiello, 2009)
Insomnia tends to becomes worse when we worry about it.
How NOT to treat insomnia.
The most common quick fixes for true insomnia — sleeping pills and alcohol — can aggravate the problem, reducing REM sleep and leaving the person with next-day blahs.
Such drugs can also lead to tolerance — a state in which increasing doses are needed to
produce an effect.
What is narcolepsy?
People with narcolepsy — 1 in 2000 of us, (from the Greek narke, “numbness,” and lepsis, “seizure”), have sudden attacks of overwhelming sleepiness, usually lasting less than 5 minutes.
Narcolepsy attacks can occur at the most inopportune times, often triggered by strong emotions.
In severe cases, the person collapses directly
into a brief period of REM sleep, with loss
of muscular tension.
What is sleep apnea?
About 1 in 20 people have sleep apnea, (apnea means “with no breath,”) and intermittently stop breathing during sleep.
After an airless minute or so, decreased blood oxygen arouses them enough to snort in air for a few seconds, in a process that repeats hundreds of
times each night, depriving them of slow-wave sleep.
Sleep apnea sufferers don’t recall these episodes
the next day.
What is a possible treatment for sleep apnea?
For many with sleep apnea, a continuous positive airway pressure (CPAP)
machine applies mild air pressure to keep the airways open, making for sounder sleeping and better
quality of life.
What are night terrors?
Night terrors target mostly children, who may sit up or walk around, talk incoherently, experience doubled heart and breathing rates, and appear terrified.
while asleep
(Hartmann, 1981).
They seldom wake up fully during an episode and recall little or nothing the next morning — at most, a fleeting, frightening image.
Unlike nightmares, which are bad dreams typically occurring in REM, night terrors usually occur during the first few hours of NREM-3.
What are sleepwalking and �sleep talking?
Sleepwalking (somnambulism)
A childhood disorder that runs in families
Somnambulism occurs during NREM-3 sleep and is usually harmless.
Few sleepwalkers recall the nighttime trips.
Sleep talking
A childhood disorder that runs in families
Sleep talking can occur in any sleep stage.
2. What Would You Answer?
Shortly after falling asleep, and hundreds of times during the night, Paola wakes up after a loud “snore” of breath, because she has stopped breathing. With which sleep disorder would she most likely be diagnosed?
B. insomnia
C. sleep apnea
D. nightmares
What do we dream?
8 in 10 dreams are marked by at least one negative event or emotion.
(Domhoff, 2007)
Common themes include repeatedly failing in an attempt to do something; being attacked, pursued, or rejected; or experiencing misfortune.
(Hall et al., 1982)
In one study, only 1 in 10 dreams among young men and 1 in 30 among young women had sexual content. (Domhoff, 1996)
“Follow your dreams, except for that one where�you’re naked at work.”�
-Attributed to comedian Henny Youngman
Take a moment to write down your dream from your last night of sleep.
Hold on to that dream while we discuss the various theories of dreaming.
What is the Freudian �theory of dreams?
Freud believed dreams existed to satisfy our own unconscious wishes. He thought dreams provided a safe place to discharge feelings and urges that would be unacceptable to express in society.
He viewed a dream’s manifest content (what we remember we dreamed) as a censored, symbolic version of its latent content, the unconscious drives and wishes (often erotic) that would be threatening if
expressed directly.
Thus, a gun might be a disguised
representation of a penis.
3. What Would You Answer?
Sigmund Freud believed that a dream’s ____ content reflected the deep, underlying meaning of the dream.
B. dissociative
C. cognitive
D. latent
What is the information-processing �theory of dreams?
The information-processing perspective proposes that dreams may help sift, sort, and fix the day’s experiences in our memory.
Brain scans confirm the link between
REM sleep and memory.
Sleep increases learning.
Researcher Robert Stickgold states “If you don’t get good sleep and enough sleep after you learn new stuff, you won’t integrate it effectively into your memories,” he warned. That helps explain why high school students with high grades slept about 25 minutes longer each night than their lower-achieving classmates.
What is the physiological function �theory of dreams?
Perhaps dreams, or the brain activity associated
with REM sleep, serve a physiological function, providing the sleeping brain with periodic stimulation.
As you will see in Unit IX, stimulating experiences preserve and expand the brain’s neural pathways.
Infants, whose neural networks are fast developing, spend much of their abundant sleep time in
REM sleep.
How does sleep and dreaming �change as we age?
During our first few months, we spend progressively
less time in REM sleep. During our first 20 years, we spend progressively less time asleep.
(Data from Snyder & Scott, 1972.)
What is the activation synthesis�theory of dreams?
According to activation-synthesis theory, dreams are the brain’s attempt to synthesize random
neural activity.
Dreams erupt from neural activation spreading upward from the brainstem.
(Antrobus, 1991; Hobson, 2003, 2004, 2009)
What is the cognitive development�theory of dreams?
Some dream researchers prefer to see dreams as
part of brain maturation and cognitive development. (Domhoff, 2010, 2011; Foulkes, 1999)
Dreams overlap with waking cognition and feature
coherent speech. They simulate reality by drawing on our concepts and knowledge.
Dreams engage brain networks that also are active during daydreaming — and so may be viewed as
intensified mind wandering, enhanced by
visual imagery.
(Fox et al., 2013)
Take a look at the dream you wrote down earlier. How do each of the theories below explain your dream?
Freudian
Activation-synthesis
Information processing
cognitive development
physiological function
What is REM rebound?
REM rebound is the tendency for REM sleep to increase
following REM sleep deprivation.
Most other mammals also experience REM
rebound, suggesting that the causes and functions of REM sleep are deeply biological.
That REM sleep occurs in mammals — and not in animals such as fish, whose behavior is less influenced by learning — fits the information-processing theory of dreams.
Learning Target 17-1 Review
How does sleep loss affect us?
Learning Target 17-1 Review cont.
What are the major sleep disorders?
Learning Target 17-2 Review
What do we dream?
Learning Target 17-2 Review cont.
What functions have theorists
proposed for dreams?