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States of
When the Human Mind Is a Buried Treasure
he daily life of Erik Ramsey would seem to be the stuff of nightmares. In 1999, at age 16, he was horribly injured
in a car accident. A blood clot in his brain stem caused a stroke, leaving Erik with a rare and permanent condition
called locked-in sy n drome (Foer, 2008). Erik cannot move or speak. He can feel an itch on his face but cannot reach
up and scratch it. The only muscles over which he has any control are those that allow him to move his eyes. Erik
uses his eye movements to communicate, answering yes (by looking up) or no (by looking down). Asked if he ever
wished he had not survived his accident, Erik looked down. For all the limitations in his life, Erik has one important
thing left: his mind.
Erik also has a loving family and a team of scientists dedicated to inventing a way for him to communicate. Sci-
entists are working tirelessly to develop computer–brain interfaces that might eventually allow Erik, and individuals
like him, to communicate with others using the ability to think (Chorost, 2011). In 2004, doctors used fMRI to pin-
point the brain locations that were active when Erik imagined himself speaking. They implanted electrodes in those
areas. Since then, Erik has been laboriously learning to think the sounds he cannot make with his voice and to do
so in a way that a computer will recognize and translate them into speech. By 2010, he was able to produce three
vowel sounds (Brumberg & Guenther, 2010). The neurosurgeons, engineers, and computer scientists who are develop-
ing the new technology hope that Erik will be able to “say” additional vowels, consonants, and perhaps even words
and sentences with his mind. They are devoted to this task because the person thinking and feeling inside his eerily
still body remains, they believe, Erik. Such is the power of consciousness in human life—that a conscious mind,
locked in a body however limited, is still a person very much worth reaching.
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126 // CHAPTER 4 // States of Consciousness
In this chapter, we review various states of consciousness, explore the world of sleep
and dreams, and consider three topics related to altered states of consciousness—
psychoactive drugs, hypnosis, and meditation.
C o n s c i o u s n e s s i s a c r u c i a l p a r t o f h u m a n e x p e r i e n c e ( B a c h m a n n , 2 0 1 1 ; C h i c a &
Bartolomeo, 2012). Our conscious awareness represents that private inner mind where
we think, feel, plan, wish, pray, imagine, and quietly relive experiences. Consider that if
we did not have private thoughts and feelings, we could not tell a lie.
In the late nineteenth and early twentieth centuries, psychology pioneer William
James (1950) described the mind as a stream of consciousness, a c o n t i n u o u s ow of
changing sensations, images, thoughts, and feelings. The content of our awareness
changes from moment to moment. Information moves rapidly in and out of conscious-
ness. Our minds can race from one topic to the next—from the person approaching
us to our physical state today to the ca where we will have lunch to our strategy
for the test tomorrow.
D u r i n g m u c h o f t h e t w e n t i e t h c e n t u r y , p s y c h o l o g i s t s f o c u s e d l e s s o n t h e s t u d y o f
mental processes and more on the study of observable behavior. More recently, the study
of consciousness has regained widespread respectability in psychology (Aly & Yonelinas,
2012; Bachmann, 2011; Graziano & Kastner, 2011). Scientists from many different elds
are interested in consciousness (Duenas & others, 2011; Silberstein & Chemero, 2012;
J. G. Taylor, 2012).
Defining Consciousness
W e c a n d e ne consciousness in terms of its two parts: awareness and arousal. Conscious-
ness i s a n i n d i v i d u a l s a w a r e n e s s o f e x t e r n a l e v e n t s a n d i n t e r n a l s e n s a t i o n s u n d e r a
condition of arousal.
Awareness includes awareness of the self and thoughts about one’s experiences. Con-
sider that on an autumn afternoon, when you see a beautiful tree, vibrant with color, you
are not simply perceiving the colors; you are also aware that you are seeing them. Hav-
ing awareness means that our sensory experiences are more than the sum of their parts.
In addition to the information we receive from the world, we have private experiences
that surround this information. William James referred to these feelings that surround
our experiences as the fringe of the stream of consciousness . This “fringe” contains those
feelings that tell us whether our experiences are familiar, whether they “feel right,
and whether they are making sense. More recently, psychologists have referred to
these thoughts about our thoughts as metacognition (Tarricone, 2011). When
you think about your thoughts—for example, when you re ect on why you
are so nervous before an exam—you are using your conscious awareness to
examine your own thought processes.
Arousal, the second part of consciousness, is the physiological state of
being engaged with the environment. Thus, a sleeping person is not conscious
in the same way that he or she would be while awake.
stream of consciousness
Term used by William James
to describe the mind as a
continuous fl ow of changing
sensations, images, thoughts,
and feelings.
An individual’s awareness of
external events and internal
sensations under a condi-
tion of arousal, including
awareness of the self and
thoughts about one’s
The Nature of Consciousness
Wi l l i a m J a m e s t h o u g h t o f
just about everyt hing psychologist s
cur r ent l y st ud y . Who kn ows what
he mi ght have acc ompl i shed wi t h t he
neur osci ence t ool s we have t oday .
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The Nature of Consciousness // 127
Consciousness and the Brain
A f a s c i n a t i n g a r e a o f i n q u i r y i n v o l v e s h o w c o n s c i o u s n e s s i s p r o d u c e d i n t h e h u m a n
brain. One view is that the two aspects of consciousness just discussed, awareness
and arousal, are associated with different parts of the brain (de Graaf, Hsieh, &
Sack, 2012; Koch, 2011). Stanilas Dehaene and his colleagues describe aware-
ness, the subjective state of being conscious of what is going on, as occurring
in a global brain workspace that involves various brain areas working in parallel
(Dehaene & Changeux, 2011; Dehaene & others, 2006; Del Cul & others, 2009;
Faugeras & others, 2012). These locations include the front-most part of the
brain—the prefrontal cortex—as well as the anterior cingulate (an area associated
with acts of will) and the association areas ( B e k i n s c h t e i n & o t h e r s , 2 0 0 9 ; D e l C u l &
others, 2009). This wide-reaching brain workspace is an assembly of neurons that
are thought to work in cooperation to produce the subjective sense of
consciousness. Areas of the prefrontal cortex appear to be espe-
cially involved in the ways that awareness goes beyond the
input of sensory information. For instance, these areas of the
brain are active when we taste complex avors, such as
umami, and track the subjective pleasure that accompanies
rewarding experiences (Kringelbach, 2005). According to
the brain workspace approach to consciousness, the wide-
spread availability of information broadcast throughout
the brain is what we experience as conscious awareness
(Baars, 2010; Bartolomei & Naccache, 2011). However,
scientists still do not know many of the details that link
consciousness with brain states.
Arousal is a physiological state determined by the reticular acti-
vating system, a network of structures including the brain stem, medulla,
and thalamus. Arousal refers to the ways that awareness is regulated: If
we are in danger, we might need to be on “high alert,but if we are in a safe environ-
ment with no immediate demands, we can relax, and our arousal may be quite low.
Theory of Mind
You might think of consciousness as the mind, that part of yourself that contains your
private thoughts and feelings. It might seem obvious that other people have private
thoughts and feelings as well, but the human ability to recognize the subjective expe-
rience of another is a true developmental accomplishment. Developmental psy-
chologists who study children’s ideas about mental states use the phrase theory
of mind to refer to individuals’ understanding that they and others think, feel,
perceive, and have private experiences (Wellman, 2011).
Developmental psychologists have used a procedure called the false belief
task to examine children’s theory of mind (Wellman, 2011). In one version of
the false belief task, the child is asked to consider the following situation (Wellman
& Woolley, 1990). Anna is a little girl who has some chocolate that she decides
to save for later. She puts it in a blue cupboard and goes outside to play. While Anna
is gone, her mother moves the chocolate to the red cupboard. When Anna comes back
in, where will she look for her chocolate? Three-year-olds give the wrong answer—they
assume that Anna will look in the red cupboard because they know (even though Anna
does not) that Anna’s mom moved the chocolate to the red one. Four-year-olds answer
correctly—they recognize that Anna does not know everything they do and that she will
believe the chocolate is where she left it (Wellman & Woolley, 1990). Success at the
false belief task is associated with academic achievement (Lecce, Caputi, & Hughes,
2011) and social competence (Leslie, German, & Polizzi, 2005), and children who
theory of mind
Individuals’ un-
derstanding that
they and others
think, feel,
perceive, and
have private
Not i ce t he
wor d
as s oci at ed
. Keep in mind
that studies showing links between
the brain and neural activity are
gener al l y cor r el at i onal st udi es .
Hav e y ou ev er
had a conver sat i on wi t h someone
who di dn t seem t o not i ce you wer e
really not into it? That person
was showi ng a t heor y of mi nd
def i ci t .
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128 // CHAPTER 4 // States of Consciousness
perform it well are better liked by their peers, in part because they are more likely to
behave kindly (Caputi & others, 2012).
T h e o r y o f m i n d i s e s s e n t i a l t o m a n y v a l u a b l e s o c i a l c a p a c i t i e s , s u c h a s e m p a t h y a n d
sympathy (Boyd, 2008; Peterson & others, 2009). Simon Baron-Cohen (1995, 2008, 2011)
is an expert on autism, a d i s o r d e r t h a t a f f e c t s c o m m u n i c a t i o n a n d s o c i a l i n t e r a c t i o n . H e
has proposed that the emergence of theory of mind is so central to human functioning that
evolution would not leave it to chance. Baron-Cohen suggests that we are born with a brain
mechanism that is ready to develop a theory of mind. This theory of mind mechanism
( TOMM ) a c c o u n t s f o r t h e f a c t t h a t n e a r l y a l l c h i l d r e n o v e r t h e a g e o f 4 p a s s t h e f a l s e b e l i e f
task. Baron-Cohen has proposed that autistic individuals lack the TOMM, a condition that
would explain their unique social de cits. Although the TOMM seems to have universal
elements, research has shown that culture plays a role in the ways this important aspect of
life unfolds (Koelkebeck & others, 2011), as we review in the Intersection.
Levels of Awareness
The ow of sensations, images, thoughts, and feelings that William James spoke of can
occur at different levels of awareness. Although we might think of consciousness as either
present or not, there are in fact shades of awareness, observed in comatose patients as
well as in everyday life. Here we consider ve levels of awareness: higher-level con-
sciousness, lower-level consciousness, altered states of consciousness, subconscious
awareness, and no awareness (Figure 4.1).
H I G H E R - L E V E L C O N S C I O U S N E S S I n controlled processes , t h e m o s t a l e r t
states of human consciousness, individuals actively focus their efforts toward a goal
(de Lange & others, 2011). For example, observe a classmate as he struggles to mas-
ter the unfamiliar buttons on his new smartphone. He does not hear you humming or
notice the intriguing shadow on the wall. His state of focused awareness illustrates
the idea of controlled processes. Controlled processes require selective attention (see
controlled processes
The most alert states of
human consciousness,
during which individuals
actively focus their efforts
toward a goal.
Involves controlled processing, in
which individuals actively focus their
efforts on attaining a goal; the most
alert state of consciousness
Includes automatic processing
that requires little attention, as
well as daydreaming
Can be produced by drugs, trauma,
fatigue, possibly hypnosis, and
sensory deprivation
Can occur when people are awake,
as well as when they are sleeping
and dreaming
Freud’s belief that some unconscious
thoughts are too laden with anxiety
and other negative emotions for
consciousness to admit them
Level of Awareness Description Examples
Altered States
of Consciousness
No Awareness
Doing a math or science
problem; preparing for a
debate; taking an at-bat in a
baseball game
Punching in a number on a cell
phone; typing on a keyboard
when one is an expert; gazing
at a sunset
Feeling the effects of having
taken alcohol or psychedelic
drugs; undergoing hypnosis to
quit smoking or lose weight
Sleeping and dreaming
Having unconscious thoughts;
being knocked out by a blow
or anesthetized
FIGURE 4.1 Levels
of Awareness Each level
of awareness has its time and
place in human life.
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The Nature of Consciousness // 129
he false belief task provides
a way to study theory of
mind, but it captures only
one aspect of our under-
standing of the minds of others.
Although children over the age of
4 in many different cultures have
acquired mastery of this task
(Shahaeian & others, 2011), theory
of mind refers to an understanding
not only of beliefs but also of a
range of mental states, including
feelings, goals, and desires. Cross-
cultural research by developmental
psychologist Henry Wellman and his
colleagues (Shahaeian & others,
2011; Wellman & Liu, 2004; Wellman
& others, 2006) has examined the
ways that aspects of theory of mind
unfold in different cultures.
In individualistic cultures, such as
the United States (Wellman & others,
2006), Germany (Kristen & others,
2006), and Australia (Shahaeian &
others, 2011), researchers have
found that children progress through
the following ve stages, in this order:
Diverse desires: Different people like and want different things.
After observing a person choose a carrot over a cookie, the
child can accurately predict that person’s preference, even if it
is different from the child’s own.
Diverse beliefs: Different people can hold different beliefs about
the same thing when both opinions are potentially true. After
nding out that a person holds a particular belief about the
location of a pet, the child can accurately predict where the
person will look for the pet.
Knowledge access: Seeing leads to knowing, and not seeing
leads to ignorance. After seeing a toy being placed inside a
container, the child can accurately predict that a person who
has not looked inside the container will not know it is there.
False beliefs: People can have invalid beliefs. The child can
predict that a person who does not have knowledge of a
change in the location of an object will not look in the new
location for it.
Hidden emotions: People may
choose to hide what they feel in-
side by altering behavior and ex-
pressions. The child is told of a
boy who is teased by his friends
but does not want to be called a
crybaby. The child can identify the
boy’s actual feelings and the face
he would show his friends.
Children in collectivistic cultures,
such as China (Wellman, Fang, &
Peterson, 2011; Wellman & others,
2006) and Iran (Shahaeian & others,
2011), develop the same comprehen-
sive theory of mind, but the order of
the stages is different. In these cul-
tures, children show a sophisticated
understanding of knowledge access
before they demonstrate mastery of
diverse beliefs. Wellman and his col-
leagues (2006) suggest that these
differences indicate that culture is
providing different “inputs” into the
developing theory of mind mechanism
(TOMM), altering the timing of these
various steps along the way.
Why might children in individualistic cultures show a mastery of
diverse beliefs before understanding knowledge access, while
those in collectivistic cultures show the opposite pattern? One
possible explanation lies in childrearing practices. In individualis-
tic cultures, children are encouraged to think for themselves,
develop their own ideas and opinions, and assert their opinions
freely. In contrast, children in collectivistic cultures, which value
harmony and familial respect, are reared to honor their elders and
to acknowledge that adults know more and have access to knowl-
edge the child may lack.
Cross-cultural research on TOMM development provides an
opportunity to see the interplay of nature (one’s genetic inheri-
tance) and nurture (environmental and social experiences). Al-
though achieving an understanding of the subjective inner life of
other human beings is potentially universal, the pathway to this
common human accomplishment may
be in uenced by culture. Even univer-
sal characteristics develop in the con-
text of a rich social world.
Consciousness and Cross-Cultural and
Developmental Psychology: How Does
Culture Shape Theory of Mind Development?
How is your theory of
mind demonstrated in your
interactions with others?
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130 // CHAPTER 4 // States of Consciousness
Chapter 3), the ability to concentrate on a speci c aspect of experience while ignoring
others (Gazzaley & Nobre, 2012). Because controlled processes demand attention and
effort, they are slower than automatic processes. Often, after we have practiced an
activity a great deal, we no longer have to think about it while doing it. It becomes
automatic and faster.
L O W E R - L E V E L C O N S C I O U S N E S S Beneath the level of controlled processes
are other levels of conscious awareness. Lower levels of awareness include automatic
processes and daydreaming.
Automatic Processes A few weeks after acquiring his smartphone, your classmate
ips it open and sends a text message in the middle of a conversation with you. He does
not have to concentrate on the keys and hardly seems aware of the device in his hand
as he continues to talk to you while nishing his lunch. Using his phone has reached
the point of automatic processing.
Automatic processes a r e s t a t e s o f c o n s c i o u s n e s s t h a t r e q u i r e l i t t l e a t t e n t i o n a n d d o n o t
interfere with other ongoing activities. Automatic processes require less conscious effort
than controlled processes (Darling & others, 2012). When we are awake, our automatic
behaviors occur at a lower level of awareness than controlled processes, but they are still
conscious behaviors. Your classmate pushed the right buttons, so at some level he appar-
ently was aware of what he was doing. This kind of automatic behavior suggests that we
can be aware of stimuli on some level without paying attention to them (Schmitz &
Wentura, 2012).
Daydreaming Another state of consciousness that involves a low level of conscious
effort is daydreaming, which lies between active consciousness and dreaming while
asleep. It is a little like dreaming while we are awake (Domhoff, 2011). Daydreams
usually begin spontaneously when we are doing something that requires less than
our full attention.
M i n d w a n d e r i n g i s p r o b a b l y t h e m o s t o b v i o u s t y p e o f d a y d r e a m i n g
(Smallwood & others, 2011). We regularly take brief side trips into our own
private kingdoms of imagery and memory while reading, listening, or working.
When we daydream, we drift into a world of fantasy. We perhaps imagine our-
selves on a date, at a party, on television, in a faraway place, or at another time
in our life. Sometimes our daydreams are about everyday events such as paying the
rent, going to the dentist, and meeting with somebody at school or work.
T h e s e m i a u t o m a t i c ow of daydreaming can be useful. As you daydream while ironing
a shirt or walking to the store, you may make plans, solve a problem, or come up with a
creative idea. Daydreams can remind us of important things ahead. Daydreaming keeps
our minds active while helping us to cope, create, and fantasize
(Mar, Mason, & Litvack, 2012). When our mind wanders, it often
wanders to the future (Baird, Smallwood, & Schooler, 2011;
Schooler & others, 2011).
A LT E R E D S T A T E S O F C O N S C I O U S N E S S Altered states
of consciousness or a w a r e n e s s are mental states that are notice-
ably different from normal awareness. Altered states of con-
sciousness can range from losing one’s sense of self-consciousness
to hallucinating. Such states can be produced by drugs, trauma,
fever, fatigue, sensory deprivation, meditation, and possibly hyp-
nosis (Hart, Ksir, & Ray, 2011). Drug use can also induce altered
states of consciousness (Fields, 2013), as we will consider later.
S U B C O N S C I O U S A W A R E N E S S In Chapter 3, we saw
that a great deal of brain activity occurs beneath the level of
conscious awareness. Psychologists are increasingly interested in
the subconscious processing of information, which can take
automatic processes
States of consciousness that
require little attention and
do not interfere with other
ongoing activities.
On e o f t h e mo s t
int erest ing t hings about mind
wand er i ng i s t hat we of t en don ’ t
realize when it happens. We just
fall into it. Hey! A r e you
payi ng at t ent i on?
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The Nature of Consciousness // 131
place while we are awake or asleep (Brosschot, Verkuil, & Thayer, 2010; Gainotti, 2012;
Straube, Mothes-Lasch, & Miltner, 2011).
Waking Subconscious Awareness When we are awake, processes are going on
just below the surface of our awareness. For example, while we are grappling with a
problem, the solution may pop into our head. Such insights can occur when a subcon-
scious connection between ideas is so strong that it rises into awareness.
Incubation refers to the subconscious processing that leads to a solution to a problem
after a break from conscious thought about the problem. Clearly, during incubation,
information is being processed even if we are unaware of that processing. Interestingly,
successful incubation requires that we rst expend effort thinking carefully about the
problem (Gonzalez-Vallejo & others, 2008).
Evidence that we are not always aware of our brain’s processing of information comes
from studies of individuals with certain neurological disorders. In one case, a woman
who suffered neurological damage was unable to describe or report the shape or size of
objects in her visual eld, although she was capable of describing other physical percep-
tions that she had (Milner & Goodale, 1995). Nonetheless, when she reached for an
object, she could accurately adjust the size of her grip to allow her to grasp the object.
Thus, she did possess some subconscious knowledge of the size and shape of objects,
even though she had no awareness of this knowledge.
Subconscious information processing can occur simultaneously in a distributed man-
ner along many parallel tracks. (Recall the discussion of parallel processing of visual
information in Chapter 3.) For example, when you look at a dog running down the street,
you are consciously aware of the event but not of the subconscious processing of the
object’s identity (a dog), its color (black), and its movement (fast). In contrast, conscious
processing occurs in sequence and is slower than much subconscious processing. Note
that the various levels of awareness often work together. You might rely on controlled
processing when memorizing material for class, but later, the answers on a test just pop
into your head as a result of automatic or subconscious processing.
Subconscious Awareness During Sleep and Dreams When we sleep and
dream, our level of awareness is lower than when we daydream, but sleep and dreams
are not best regarded as the absence of consciousness (Hobson & Voss, 2011; Windt &
Noreika, 2011). Rather, they are low levels of consciousness.
Researchers have found that when people are asleep, they remain aware of external
stimuli to some degree. In sleep laboratories, when people are clearly asleep (as deter-
mined by physiological monitoring devices), they are able to respond to faint tones by
pressing a handheld button (Ogilvie & Wilkinson, 1988). In one study, the presentation
of pure auditory tones to sleeping individuals activated auditory processing regions of
the brain, whereas participants’ names activated language areas, the amygdala, and the
prefrontal cortex (Stickgold, 2001). We return to the topics of sleep and dreams in the
next section.
N O A W A R E N E S S The term unconscious generally applies to someone who has
been knocked out by a blow or anesthetized, or who has fallen into a deep, prolonged
unconscious state (Laureys & Schiff, 2012; Lobo & Schraag, 2011). However, Sigmund
Freud (1917) used the term unconscious in a very different way: Unconscious thought ,
said Freud, is a reservoir of unacceptable wishes, feelings, and thoughts that are beyond
conscious awareness. In other words, Freud’s interpretation viewed the unconscious as a
storehouse for vile thoughts and impulses. He believed that some aspects of our experi-
ence remain unconscious for good reason, as if we are better off not knowing about
them. For example, from Freud’s perspective, the human mind is full of disturbing
impulses such as a desire to have sex with our parents.
Although Freuds interpretation remains controversial, psychologists now widely
accept that unconscious processes do exist. Recently, researchers have found that many
mental processes (thoughts, emotions, goals, and perceptions) can occur outside of
awareness (Ashby, Glockner, & Dickert, 2011; Gainotti, 2012). These unconscious
unconscious thought
According to Freud, a reser-
voir of unacceptable wishes,
feelings, and thoughts that
are beyond conscious
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132 // CHAPTER 4 // States of Consciousness
processes can have a large impact on behavior. In Chapter 3, for example, we saw how
stimuli presented outside of awareness can in uence thoughts and behaviors, and in
Chapter 5 we will see that many forms of learning operate without the need for aware-
ness. As psychologists continue to study the ways that unconscious information process-
ing can in uence behavior, the capacities of such operations seem amazing (Bargh &
Morsella, 2009). If unconscious processes can do so much, why do humans need con-
scious awareness? What does conscious awareness do that unconscious processes cannot?
To unravel this age-old mystery, see Challenge Your Thinking.
n what ways are human be-
ings better adapted to the
environment than lower ani-
mals because they have private
awareness? Why is it adaptive
for human beings, unlike other
animals, not only to sense and
perceive the world but also to
privately feel ourselves doing
so? Psychologists and philoso-
phers have long puzzled over
these questions. To address
them, let’s rst consider some of
the purposes of consciousness.
Perhaps the most obvious
function of awareness is to over-
ride automatic and unconscious
processes when these are likely
to produce errors (Evans, 2010; Geary, 2004). Consider all the
times you have made a mistake and realized, “I just wasn’t think-
ing.” Conscious awareness allows us to harness our mental abili-
ties to think our way past our ordinary routine. The human social
world is highly complex and variable. Some have suggested that
this complex social world requires awareness (Geary, 2004;
Mercier & Sperber, 2011) and lays the foundation for the
emergence of culture (Baumeister & Masicampo, 2010).
Without consciousness, moreover, we could not engage in
mental time travel. John Bargh (2004) described unconscious,
automatic processes as tied to the present moment—a kind of
“minding the store” mode—while conscious thought ventures into
the realm of future (and past) states. The abilities to think into
the future, to plan, and to imagine have often been recognized as
essential features of consciousness (Baumeister & Masicampo,
2010; Heidegger, 1927/1962). Certainly, the ability to think back
into the past to seek ways to correct prior mistakes is enormously
important, as is the ability to plan for imagined futures.
Consciousness also allows us to reason and use logic, the ba-
sis of scienti c knowledge (Evans, 2002, 2010). Consciousness
empowers us to ask why and to
know the reasons behind our
knowledge about the world. Thus,
awareness is crucial to critical
thinking. Further, the conscious
organism has the capacity to ask
questions not only about what is
happening in the world or even
about internal thoughts and feel-
ings, but also about existence
itself: Why am I here? What pur-
pose do I serve? Thus, con-
sciousness brings the issue of
personal signi cance to the fore.
In grappling with the purpose
of consciousness, Nicholas
Humphrey (2000, 2006) sug-
gested the provocative possibil-
ity that it is the very mysteriousness of consciousness that
explains its adaptive signi cance. For Humphrey, awareness
imbues human life with a vital survival need, raising the self be-
yond the natural world to something larger and potentially better.
Private awareness is the foundation for ideas like the soul,
promoting the feeling of a self that is not limited by space or
time. Because we know that others possess a private self, we
are motivated to treat them with respect and kindness—in other
words, to behave ethically (Tamburrini & Mattia, 2011).
Consciousness, then, makes
human life matter to us in ways
that in uence our capacity to
survive and to promote the sur-
vival of other members of our
species. In answer to the ques-
tion “Why does consciousness
matter?” Humphrey (2006,
p. 131) replied, “Conscious-
ness matters because it is its
function to matter.
Why Do We Have Conscious Awareness?
What Do You Think?
Why are you better off
because you have
What would your life be like
without awareness?
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Sleep and Dreams // 133
1. The term metacognition refers to
A. the study of cognitive research.
B. thinking about thought processes.
C. cognition that is subliminal.
D. stream of consciousness thinking.
2. All of the following are examples of
automatic processes except
A. a student solving a math problem.
B. a runner jogging.
C. a person talking to a friend.
D. a taxi driver operating a car.
3. Sleep and dreams are most accurately
viewed as
A. the absence of consciousness.
B. intermittent consciousness.
C. low levels of consciousness.
D. high levels of consciousness.
APPLY IT! 4. Xavier is a student in
Intro Psych. He has attended every class and
taken detailed notes. Before the first exam,
he studies and takes practice tests. On the
morning of the test, however, he feels sud-
denly blank. Xavier takes a deep breath and
starts answering each question one by one,
taking guesses on many questions. The next
week, Xavier is thrilled to learn that he got a
100 percent on the exam. He later tells a
friend, “I just took guesses and still got a
perfect score. Next time I should not even
bother studying!” Which of the following is
true of Xavier’s plan?
A. It is a good idea, since a lot of psychol-
ogy is just common sense.
B. It is a bad idea. Xavier’s grade shows
that controlled and subconscious pro-
cesses work together. Controlled pro-
cesses helped him learn the material so
that he was able to take good guesses.
C. Xavier’s plan is not a good idea, because
his subconscious helped him on this
test, but such processing cannot be
counted on to work all the time.
D. Xavier’s plan is a good one. His experi-
ence demonstrates that controlled
processes are generally not helpful in
academic work.
You already know that sleep involves a decrease in body movement and (typically) closed
eyes. What is sleep, more precisely? We can de ne sleep as a natural state of rest for
the body and mind that involves the reversible loss of consciousness. Sleep must
be important, because it takes up about one-third of our lifetime, more than
anything else we do. Why is sleep so crucial? Before tackling this question,
let’s rst see how sleep is linked to our internal biological rhythms.
Biological Rhythms and Sleep
Biological rhythms a r e p e r i o d i c p h y s i o l o g i c a l uctuations in the body.
We are unaware of most biological rhythms, such as the rise and fall of
hormones and accelerated and decelerated cycles of brain activity, but they
can in uence our behavior. These rhythms are controlled by biological clocks,
which include annual or seasonal cycles such as the migration of birds and the
hibernation of bears, and 24-hour cycles such as the sleep/wake cycle and temperature
changes in the human body. Let’s further explore the body’s 24-hour cycles.
C I R C A D I A N R H Y T H M S Circadian rhythms a r e d a i l y b e h a v i o r a l o r p h y s i o l o g -
ical cycles. Daily circadian rhythms involve the sleep/wake cycle, body temperature,
blood pressure, and blood sugar level (Jan & others, 2012; Stephenson & others, 2012).
For example, body temperature uctuates about 3 degrees Fahrenheit in a 24-hour day,
peaking in the afternoon and reaching its lowest point between 2 a.m. and 5 a.m.
Researchers have discovered that the body monitors the change from day to night by
means of the suprachiasmatic nucleus (SCN) , a small brain structure that uses input
from the retina to synchronize its own rhythm with the daily cycle of light and dark
(Oliver & others, 2012). Output from the SCN allows the hypothalamus to regulate daily
rhythms such as temperature and hunger and the reticular formation to regulate daily
rhythms of sleep and wakefulness (Figure 4.2). Although a number of biological clocks
seem to be involved in regulating circadian rhythms, researchers have found that the SCN
is the most important (Han & others, 2012).
Many individuals who are totally blind experience lifelong sleeping problems because
their retinas cannot detect light. These people have a kind of permanent jet lag and
A natural state of
rest for the body
and mind that
involves the
reversible loss of
Periodic physi-
ological fl uctua-
tions in the body,
such as the rise
and fall of hor-
mones and
accelerated and
cycles of brain ac-
tivity, that can in-
uence behavior.
circadian rhythms
Daily behavioral or physi-
ological cycles that involve
the sleep/wake cycle, body
temperature, blood pres-
sure, and blood sugar level.
suprachiasmatic nucleus (SCN)
A small brain structure that
uses input from the retina to
synchronize its own rhythm
with the daily cycle of light
and dark; the body’s way of
monitoring the change from
day to night.
Sleep and Dreams
How, wher e, an d
wi t h whom we sl eep ar e al l i nf l uenc ed
by cul t u r e. I n t he Uni t e d St at es, i nf ant s
typically sleep alone, and parents are
di s cour aged f r om s l eepi ng wi t h t hei r
infant s. I n ot her count ries, such
cosl eepi ng is an accept ed pract ice.
Some cul t u r es e ncour a ge a f ami l y
bed wher e eve r yone sl eeps
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134 // CHAPTER 4 // States of Consciousness
Cerebral Cortex
Nucleus (SCN)
Format ion
Changing to a night-shift job can desynchronize our
biological clocks and affect our circadian rhythms and
periodic insomnia because their circadian rhythms
often do not follow a 24-hour cycle (Waller,
Bendel, & Kaplan, 2008).
D E S Y N C H R O N I Z I N G T H E B I O -
LOGICAL CLOCK Biological clocks
can become desynchronized , or thrown
off their regular schedules. Among the
circumstances of life that can introduce
irregularities into our sleep are jet
travel, changing work shifts, and insom-
nia (the inability to sleep) (Lack &
Wright, 2012; Vaillières & Bastille-
Denis, 2012). What effects might such
irregularities have on circadian rhythms?
I f y o u y from Los Angeles to New
York and then go to bed at 11 p.m. eastern
time, you may have trouble falling asleep
because your body is still on west coast time.
Even if you sleep for 8 hours that night, you
may have a hard time waking up at 7 a.m.
eastern time, because your body thinks it is
4 a.m. If you stay in New York for several days,
your body will adjust to this new schedule.
T h e j e t l a g y o u e x p e r i e n c e w h e n y o u y from Los
Angeles to New York occurs because your body time is out of phase,
or synchronization, with clock time (Paul & others, 2011). Jet lag is the result of two or
more body rhythms being out of sync. You usually go to bed when your body tempera-
ture begins to drop, but in your new location, you might be trying to go to sleep when
it is rising. In the morning, your adrenal glands
release large doses of the hormone cortisol to help
you wake up. In your new geographic time zone, the
glands may be releasing this chemical just as you are
getting ready for bed at night.
C i r c a d i a n r h y t h m s m a y a l s o b e c o m e d e s y n c h r o -
nized when shift workers change their work hours
(Kim, Woo, & Kim, 2012; Waage & others, 2012). A
number of near accidents in air travel have been associ-
ated with pilots who have not yet become synchronized
to their new shifts and are not working as ef ciently as
usual (Powell, Spencer, & Petrie, 2011). Shift-work
problems most often affect night-shift workers who
never fully adjust to sleeping in the daytime after their
work shifts. Such workers may fall asleep at work and
are at increased risk for heart disease and gastrointes-
tinal disorders (Puttonen, Viitasalo, & Harma, 2011).
R E S E T T I N G T H E B I O L O G I C A L C L O C K I f
your biological clock for sleeping and waking becomes
desynchronized, how can you reset it? With regard to
jet lag, if you take a transoceanic ight and arrive at
your destination during the day, it is a good idea to
spend as much time outside in the daylight as possible.
Bright light during the day, especially in the morning,
increases wakefulness, whereas bright light at night
delays sleep (Paul & others, 2011).
Nucleus The supra-
chiasmatic nucleus (SCN)
plays an important role in
keeping our biological clock
running on time. The SCN is
located in the hypothalamus.
It receives information from
the retina about light, which
is the external stimulus that
synchronizes the SCN. Output
from the SCN is distributed to
the rest of the hypothalamus
and to the reticular formation.
The Need for Sleep
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Sleep and Dreams // 135
Wh y w o u l d m e l a t o n i n b e
par t i cul ar l y hel pf ul f or eas t war d
but not west war d t r avel ?
Hours of Sleep pe
24-Hour Period
Rab b it
Rhesus monkey
FIGURE 4.3 From Bats to Horses:
The Wide Range of Sleep in Animals
We might feel envious of bats, which sleep nearly
20 hours a day, and more than a little in awe of
horses, still running on just under 3 hours of rest.
Researchers are studying melatonin, a hormone that increases at night in
humans, for its possible effects in reducing jet lag (Jackson 2010; Paul &
others, 2011; Sack, 2010). Studies have shown that a small dosage of mel-
atonin can reduce jet lag by advancing the circadian clock—an effect that
makes it useful for eastward but not westward jet lag (Herman & others,
Why Do We Need Sleep?
All animals require sleep. Furthermore, the human body regulates sleep, as it
does eating and drinking, and this fact suggests that sleep may be just as essen-
tial for survival. Yet why we need sleep remains a bit of a mystery.
T H E O R I E S O N T H E N E E D F O R S L E E P A variety of theories have
been proposed for the need for sleep (Harrison, 2012). First, from an evolutionary
perspective, sleep may have developed because animals needed to protect themselves
at night. The idea is that it makes sense for animals to be inactive when it is dark,
because nocturnal inactivity helps them to avoid both becoming other animals’ prey
and injuring themselves due to poor visibility.
A second possibility is that sleep is a way to conserve energy. Spending a large chunk
of any day sleeping allows animals to conserve their calories, especially when food is
scarce (Siegel, 2005). For some animals, moreover, the search for food and water is
easier and safer when the sun is up. When it is dark, it is adaptive for these animals to
save their energy. Animals that are likely to serve as someone else’s food sleep the least
of all. Figure 4.3 illustrates the average amount of sleep per day of various animals.
A third explanation for the need for sleep is that sleep is restorative (Frank, 2006).
Scientists have proposed that sleep restores, replenishes, and rebuilds the brain and
body, which the day’s waking activities can wear out. This idea ts with the feeling
of being tired before we go to sleep and restored when we wake up. In support of the
theory of a restorative function of sleep, many of the body’s cells show increased produc-
tion and reduced breakdown of proteins during deep sleep (Aton & others, 2009; Vazquez
& others, 2008). Protein molecules are the building blocks needed for cell growth and for
repair of damage from factors such as stress. Results of a recent study linked short
sleep duration with higher T-cell and lower NK-cell activity, indicating higher
stress levels and lower immune system functioning (Fondell & others, 2011).
A nal explanation for the need for sleep centers on the role of sleep in
brain plasticity (Frank & Benington, 2006; Tononi & Cirelli, 2011). Recall
from Chapter 3 that the plasticity of the brain refers to its capacity to
change in response to experience. Sleep has been recognized as playing
an important role in the ways that experiences in uence the brain. For
example, neuroscientists recently have argued that sleep enhances synaptic
connections between neurons (Timofeev, 2011). Findings such as these suggest an
important role for sleep in the consolidation of memories (Lewis & others, 2011;
Walker, 2012). A research review concluded that sleep is vital to the consolidation
of memory, whether memory for speci c information, for skills, or for emotional
experiences (Diekelmann, Wilhelm, & Born, 2009). One possible explanation is
that during sleep the cerebral cortex is free to conduct activities that strengthen
memory associations, so that memories formed during recent waking hours can be
integrated into long-term memory storage. Lost sleep often results in lost memories.
So, if you are thinking about studying all night for your next test,
you might want to think again. Sleep can enhance your memory. In
one study, participants who had studied word lists the day before per-
formed better in a recall test for those words if they had had a good
night’s sleep before the test (Racsmany, Conway, & Demeter, 2010).
Participants who were tested prior to sleep did not perform as well.
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136 // CHAPTER 4 // States of Consciousness
We do our best when we sleep more than 8 hours a night
(Habeck & others, 2004). Lack of sleep is stressful and has an
impact on the body and the brain (Koenis & others, 2011;
Monk, 2012). When deprived of sleep, people have trouble
paying attention to tasks and solving problems (Jackson &
others, 2011). Studies have shown that sleep deprivation
decreased brain activity in the thalamus and the prefrontal cor-
tex (Libedinsky & others, 2011) and reduced the complexity
of brain activity (Jeong & others, 2001). The tired brain must
compensate by using different pathways or alternative neural
networks when thinking (Koenis & others, 2011). Sleep depri-
vation can even in uence moral judgment. Following 53 hours
of wakefulness, participants in a recent study had more dif -
culty making moral decisions and were more likely to agree
with decisions that violated their personal standards (Killgore &
others, 2007).
A l t h o u g h s l e e p i s u n q u e s t i o n a b l y k e y t o o p t i m a l p h y s i c a l
and mental performance, many of us do not get suf cient sleep.
In a recent national survey of more than 1,500 U.S. adults con-
ducted by the National Sleep Foundation (2011), 43 percent of
19- to 64-year-olds reported that they rarely or ever get a good
night’s sleep on weeknights. Sixty percent said that they expe-
rience a sleep problem every night or almost every night, such
as waking during the night, waking too early, or feeling
tired when they wake up in the morning. A majority stated that they get slightly less
than 7 hours of sleep a night on weeknights, and 15 percent indicated that they sleep
less than 6 hours a night.
W h y d o A m e r i c a n s g e t t o o l i t t l e s l e e p ? P r e s s u r e s a t w o r k a n d s c h o o l , f a m i l y r e s p o n -
sibilities, and social obligations often lead to long hours of wakefulness and irregular
sleep/wake schedules (Artazcoz & others, 2009). Not having enough hours to do all that
we want or need to do in a day, we cheat on our sleep. As a
result we may suffer from a “sleep debt,an accumulated level
of exhaustion.
Stages of Wakefulness
and Sleep
Have you ever been awakened from your sleep and been totally
disoriented? Have you ever awakened in the middle of a dream
and suddenly gone right back into the dream as if it were a movie
running just under the surface of your consciousness? These two
circumstances re ect two distinct stages in the sleep cycle.
Stages of sleep correspond to massive electrophysiological
changes that occur throughout the brain as the fast, irregular,
and low-amplitude electrical activity of wakefulness is replaced
by the slow, regular, high-amplitude waves of deep sleep. Using
the electroencephalograph (EEG) to monitor the brain’s electri-
cal activity, scientists have identi ed two stages of wakefulness
and ve stages of sleep.
W A K E F U L N E S S S T A G E S When people are awake,
their EEG patterns exhibit two types of waves: beta and alpha.
Beta waves re ect concentration and alertness. These waves are
Sleep researchers record Randy Gardner’s behavior (he’s
the person doing pushups) during his 264-hour period
of sleep deprivation. Most people who try to stay up
even one night have diffi culty remaining awake from
3 A.M. to 6 A.M.
Sensing that he was about to doze off, the air bag on
Wayne’s computer rapidly deployed.
Used by permission of CartoonStock,
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Sleep and Dreams // 137
the highest in frequency and lowest in amplitude. This means that the waves go up and
down a great deal, but they do not have very high peaks or very low ebbs. They also are
more desynchronous than other waves, meaning they do not form a very consistent pat-
tern. Inconsistent patterning makes sense given the extensive variation in sensory input
and activities we experience when we are awake.
When we are relaxed but still awake, our brain waves slow down, increase in ampli-
tude, and become more synchro n ous, or regular. These waves, associated with relaxation
or drowsiness, are called alpha waves.
T h e ve stages of sleep also are differentiated by the types of wave patterns
detected with an EEG, and the depth of sleep varies from one stage to another, as we
now consider.
S L E E P S T A G E S 1 4 Stage 1 sleep is characterized by drowsy sleep. In
this stage, the person may experience sudden muscle movements called myo-
clonic jerks . E E G s o f i n d i v i d u a l s i n t h i s s t a g e a r e c h a r a c t e r i z e d b y theta
waves, which are even slower in frequency and greater in amplitude than
alpha waves. The difference between just being relaxed and stage 1 sleep
is gradual. Figure 4.4 shows the EEG pattern of stage 1 sleep, along with
the EEG patterns for the other four sleep stages and beta and alpha waves.
Beta waves
High-frequency patterns that reflect
concentration and alertness
EEG Pattern Pattern Format Pattern Characteristics
Alpha waves
Lower-frequency patterns associated
with being relaxed or drowsy
Stage 1
Light sleep lasting up to 10 minutes;
includes theta waves (low frequency,
low amplitude)
Stage 2
Deeper sleep characterized by occasional
“sleep spindles” (brief high-frequency
waves), lasting up to 20 minutes
Stage 3
Progressively more muscle relaxation
and emergence of delta waves (slower);
lasts up to 40 minutes
Stage 4
Deep sleep when sleeper is difficult to
rouse; delta waves—large, slow brain
Stage 5: REM sleep
Instead of reentering stage 1 sleep, the
individual shows EEG patterns similar to
those of relaxed wakefulness; most
dreaming occurs in this stage; lasts for
about 10 minutes in first sleep cycle of
the night and up to 1 hour in the last
Characteristics and
Formats of EEG
Recordings During
Stages of Sleep Even
while you are sleeping, your
brain is busy. No wonder you
sometimes wake up feeling
Wa t c h p e o p l e i n y o u r c l a s s e s
fight to stay awakeyoull see their
head s j er k up. Thi s f i r st st age of
sl eep of t en i nvol ves t he f eeli ng of
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138 // CHAPTER 4 // States of Consciousness
In stage 2 sleep , muscle activity decreases, and the person is no longer consciously
aware of the environment. Theta waves continue but are interspersed with a de ning
characteristic of stage 2 sleep: sleep spindles. These involve a sudden increase in wave
frequency (Andrillon & others, 2011). Stages 1 and 2 are both relatively light stages of
sleep, and if people awaken during one of these stages, they often report not having been
asleep at all.
Stage 3 sleep and stage 4 sleep are characterized by delta waves, t h e s l o w e s t a n d
highest-amplitude brain waves during sleep. These two stages are often referred to as
delta sleep. Distinguishing between stage 3 and stage 4 is dif cult, although typically
stage 3 is characterized by delta waves occurring less than 50 percent of the time and
stage 4 by delta waves occurring more than 50 percent of the time. Delta sleep is our
deepest sleep, the time when our brain waves are least like waking brain waves. It is
during delta sleep that it is the most dif cult to wake sleepers. This is also the stage
when bedwetting (in children), sleepwalking, and sleep talking occur. When awakened
during this stage, people usually are confused and disoriented.
R E M S L E E P After going through stages 14, sleepers drift up through the sleep
stages toward wakefulness. Instead of reentering stage 1, however, they enter stage
5 sleep, a different form of sleep called REM ( rapid eye movement ) sleep (Colrain
& Baker, 2012). REM sleep i s a n a c t i v e s t a g e o f s l e e p d u r i n g w h i c h d r e a m i n g
occurs. The EEG pattern for REM sleep shows fast waves similar to those of relaxed
wakefulness, and the sleepers eyeballs move up and down and from left to right
(Figure 4.5).
S p e c i a l i s t s r e f e r t o s t a g e s 1 4 a s non-REM sleep. Non-REM sleep is characterized
by a lack of rapid eye movement and little dreaming. A person who is awakened dur-
ing REM sleep is more likely to report having dreamed than when awakened at any
other stage (Marzano & others, 2011). Even people who claim they rarely dream fre-
quently report dreaming when they are awakened during REM sleep. The longer the
period of REM sleep, the more likely the person will report dreaming. Dreams also
occur during slow-wave or non-REM sleep, but the frequency of dreams in these stages
is relatively low (McNamara, McLaren, & Durso, 2007), and we are less likely to
remember these dreams. Reports of dreaming by individuals awakened from REM
sleep are typically longer, more vivid, more physically active, more emotionally
charged, and less related to waking life than reports by those awakened from non-REM
sleep (Hobson, 2004).
REM sleep also likely plays a role in memory (Blagrove & others, 2011). Research-
ers have presented individuals with unique phrases before they go to bed. When they are
awakened just before they begin REM sleep, they remember less the next morning than
when they are awakened during the other sleep stages (Stickgold & Walker, 2005).
S L E E P C Y C L I N G T H R O U G H T H E N I G H T T h e ve stages of
sleep we have considered make up a normal cycle of sleep. As shown in
Figure 4.6, one of these cycles lasts about 90 to 100 minutes and recurs
several times during the night. The amount of deep sleep (stages 3 and
4) is much greater in the rst half of a nights sleep than in the second
half. Most REM sleep takes place toward the end of a night’s sleep, when
the REM stage becomes progressively longer. The night’s rst REM
stage might last for only 10 minutes, but the nal REM stage might
continue for as long as an hour. During a normal night of sleep, indi-
viduals will spend about 60 percent of sleep in light sleep (stages 1 and 2),
20 percent in delta or deep sleep, and 20 percent in REM sleep (Webb,
S L E E P A N D T H E B R A I N T h e ve sleep stages are associated with
distinct patterns of neurotransmitter activity initiated in the reticular formation,
REM sleep
An active stage of sleep
during which dreaming
FIGURE 4.5 REM Sleep During
REM sleep, your eyes move rapidly, as if
following the images moving in your dreams.
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Sleep and Dreams // 139
the core of the brain stem (Peigneux, Urbain,
& Schmitz, 2012). In all vertebrates, the reticu-
lar formation plays a crucial role in sleep and
arousal (see Figure 4.2). As previously noted,
damage to the reticular formation can result in
coma and death.
Three important neurotransmitters involved
in sleep are serotonin, norepinephrine, and
acetylcholine (Koziorynska & Rodriquez,
2011). As sleep begins, the levels of neu-
rotransmitters sent to the forebrain from the
reticular formation start dropping, and they
continue to fall until they reach their lowest
levels during the deepest sleep stage—stage 4.
REM sleep (stage 5) is initiated by a rise in
acetylcholine, which activates the cerebral cor-
tex while the rest of the brain remains rela-
tively inactive. REM sleep ends when there is
a rise in serotonin and norepinephrine, which
increase the level of forebrain activity nearly
to the awakened state (Miller & O’Callaghan,
2006). You are most likely to wake up just
after a REM period. If you do not wake up
then, the level of the neurotransmitters falls
again, and you enter another sleep cycle.
Sleep Throughout the Life Span
Getting suf cient sleep is important at every period in human life (Lee & Rosen, 2012).
Figure 4.7 shows how total sleep time and time spent in each type of sleep vary over
the human life span.
Sleep may bene t physical growth and brain development in infants and children. For
example, deep sleep coincides with the release of growth hormone in children. Children
are more likely to sleep well when they avoid caffeine, experience a regular bedtime
routine, are read to before going to bed, and do not have a television in their bedroom
(Mindell & others, 2009).
As children age, their sleep patterns change. Many adolescents stay up later at night
and sleep longer in the morning than they did when they were children, and these shift-
ing sleep patterns may in uence their academic work. During adolescence, the brain,
especially the cerebral cortex, is continuing to develop, and the adolescent’s need for
sleep may be linked to this brain development (Colrain & Baker, 2011).
Mary Carskadon and her colleagues have conducted a number of studies on adolescent
sleep patterns (Carskadon, 2006, 2011a, 2011b; Crowley & Carskadon, 2010; Tarokh &
Carskadon, 2010). They found that when given the opportunity, adolescents will sleep
an average of 9 hours and 25 minutes a night. Most, however, get considerably less than
9 hours of sleep, especially during the week. This shortfall creates a sleep debt that
adolescents often attempt to make up on the weekend.
The researchers also found that older adolescents tend to be sleepier during the day
than younger adolescents. They theorized that this sleepiness was not due to academic
work or social pressures. Rather, their research suggests that adolescents’ biological
clocks undergo a shift as they get older, delaying their period of wakefulness by about
an hour. A delay in the nightly release of the sleep-inducing hormone melatonin seems
to underlie this shift. Melatonin is secreted at about 9:30 p.m. in younger adolescents and
approximately an hour later in older adolescents. Based on her research, Carskadon has
St ag e
Hour of the night
REM sleep
Midnight 1
FIGURE 4.6 Cycling Through a Nights Sleep During a night’s
sleep, we go through several cycles. Depth of sleep decreases, and REM sleep
(shown in green) increases as the night progresses. In this graph, the person
is depicted as awakening at about 5 A.M. and then going back to sleep for
another hour. > How many sleep cycles are presented? > How many times
does thesleeper wake up? > Trace the rise and fall of the neurotransmitters
acetylcholine, serotonin, and norepinephrine in the sleep cycle depicted.
Has this sleeper achieved a good night’s rest? Why or why not?
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140 // CHAPTER 4 // States of Consciousness
suggested that early school starting times may cause grogginess, inattention in class, and
poor performance on tests. One study revealed that just a 30-minute delay in school start
time was linked to improvements in adolescents’ sleep, alertness, mood, and health
(Owens, Belon, & Moss, 2010).
Do sleep patterns change in emerging adulthood (18–25 years of age)? Research
indicates that they do (Galambos, Howard, & Maggs, 2011). In a recent study, the
weekday bedtimes and rise times of rst-year college students were approximately
1 hour 15 minutes later than those of high school seniors (Lund & others, 2010).
However, the rst-year college students had later bedtimes and rise times than
third- and fourth-year college students, indicating that at about 20–22 years of age,
a reverse in the timing of bedtimes and rise times occurs.
Sleep patterns also change as people age through the middle-adult (40s and
50s) and late-adult (60s and older) years (Malhotra & Desai, 2010; Nakamura
& others, 2011; Olbrich & Dittmer, 2011). Many adults in these age spans
go to bed earlier at night and wake up earlier in the morning than they did
in their younger years. As well, beginning in the 40s, individuals report that
they are less likely to sleep through the entire night than when they were
younger. Middle-aged adults also spend less time in deep sleep than they
did before their middle years.
A r e c e n t s t u d y f o u n d t h a t c h a n g e s i n s l e e p d u r a t i o n a c r o s s ve years in
middle age were linked to cognitive abilities such as problem solving and
memory (Ferrie & others, 2011). In this study, a decrease from 6, 7, or 8 hours of
sleep and an increase from 7 or 8 hours were related to lower scores on most cognitive
assessments. In late adulthood, approximately 50 percent of older adults complain of hav-
ing dif culty sleeping (Neikrug & Ancoli-Israel, 2010). Poor sleep can result in earlier
death and is linked to a lower level of cognitive functioning (Naismith, Lewis, & Rogers,
2011; Tuckman & others, 2011).
FIGURE 4.7 Sleep Across the Human Life Span With age, humans require less sleep.
Total daily sleep (hours)
Newborn Infants Children Adolescents Adults Older adults
Age in months Age in years
REM sleep
Non-REM sleep
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Sleep and Dreams // 141
Sleep and Disease
S l e e p p l a y s a r o l e i n a l a r g e n u m b e r o f h e a l t h p r o b l e m s , d i s e a s e s , a n d d i s o r d e r s ( F o n t a n a
& Wohlgemuth, 2010; Patel & others, 2012). For example, stroke and asthma attacks
are more common during the night and in the early morning, probably because of
changes in hormones, heart rate, and other characteristics associated with sleep
( T e o d o r e s c u & o t h e r s , 2 0 0 6 ) . S l e e p l e s s n e s s i s a l s o a s s o c i a t e d w i t h o b e s i t y a n d h e a r t
disease (Sabanayagam & Shankar, 2010).
Neurons that control sleep interact closely with the immune system (Imeri & Opp,
2009). As anyone who has had the u knows, infectious diseases make us sleepy. The
probable reason is that chemicals called cytokines, produced by the body’s cells while
we are ghting an infection, are powerfully sleep-inducing (Besedovsky, Lange, & Born,
2012). Sleep may help the body conserve energy and other resources it needs to over-
come infection (Irwin & others, 2006).
Sleep problems af ict most people who have psychological disorders, including those
with depression (Eidelman & others, 2012; Hidaka, 2012). Individuals with depression
often awaken in the early hours of the morning and cannot get back to sleep, and they
often spend less time in delta wave or deep sleep than do non-depressed individuals.
Sleep problems are common in many other disorders as well, including Alzheimer
disease, stroke, and cancer (Banthia & others, 2009; Fleming & Davidson, 2012; Gaig
& Iranzo, 2012). In some cases, however, these problems may be due not to the disease
itself but to the drugs used to treat the disease.
Sleep Disorders
Many individuals suffer from undiagnosed and untreated sleep disorders that leave them
struggling through the day, feeling unmotivated and exhausted (Edinger & Morin, 2012;
Rajaratnam & others, 2011). Some of the major sleep problems are insomnia, sleepwalk-
ing and sleep talking, nightmares and night terrors, narcolepsy, and sleep apnea.
I N S O M N I A A c o m m o n s l e e p p r o b l e m i s insomnia, the inability to sleep.
Insomnia can involve a problem in falling asleep, waking up during the night, or
waking up too early (Gehrman, Findley, & Perlis, 2012). In the United States, as
many as one in ve adults has insomnia (Pearson, Johnson, & Nahin, 2006). Insom-
nia is more common among women and older adults, as well as individuals who are
thin, stressed, or depressed (National Sleep Foundation, 2007).
For short-term insomnia, most physicians prescribe sleeping pills. However,
most sleeping pills stop working after several weeks of nightly use, and their long-
term use can interfere with good sleep. Mild insomnia often can be reduced by
simply practicing good sleep habits, such as always going to bed at the same time,
even on weekends, and sleeping in a dark, quiet place. In more serious cases,
researchers are experimenting with light therapy, melatonin supplements, and
other ways to alter circadian cycles (Cardinali & others, 2011; Lichstein, Vander
Wal, & Dillon, 2012; Zeitzer, Friedman, & Yesavage, 2011). Behavioral changes
(such as avoiding naps and setting an alarm in the morning) can help insomni-
acs increase their sleep time and awaken less frequently in the night (Jernelov
& others, 2012).
S L E E P W A L K I N G A N D S L E E P T A L K I N G Somnambulism is the formal term for
sleepwalking, which occurs during the deepest stages of sleep (Umanath, Sarezky, &
Finger, 2011). For many years, experts believed that somnambulists were acting out
their dreams. However, somnambulism takes place during stages 3 and 4, usually early
in the night, when a person is unlikely to be dreaming (Zadra & Pilon, 2012).
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142 // CHAPTER 4 // States of Consciousness
The speci c causes of sleepwalking have not been identi ed, but it is more likely to
occur when individuals are sleep deprived or have been drinking alcohol. There is noth-
ing abnormal about sleepwalking, and despite superstition, it is safe to awaken sleepwalk-
ers. In fact, they probably should be awakened, as they may harm themselves wandering
around in the dark (Swanson, 1999).
Another quirky night behavior is sleep talking, or somniloquy. If you interrogate sleep
talkers, can you nd out what they did, for instance, last Thursday night? Probably not.
Although sleep talkers will converse with you and make fairly coherent statements, they
are soundly asleep. Thus, even if a sleep talker mumbles a response to your question,
do not count on its accuracy.
R e c e n t l y , a f e w c a s e s o f a n e v e n r a r e r s l e e p b e h a v i o r h a v e c o m e t o l i g h t s l e e p e a t -
ing. Ambien is a widely prescribed sleep medication for insomnia. Some Ambien users
began to notice odd things upon waking up from a much-needed good night’s sleep,
such as candy wrappers strewn around the room, crumbs in the bed, and food missing
from the refrigerator. One woman gained 100 pounds without changing her awake eat-
ing or exercise habits. How could this be? Dr. Mark Mahowald, the medical director of
the Minnesota Regional Sleep Disorders Center in Minneapolis, has con rmed that sleep
eating may be a side effect of using Ambien (McNamara, 2009).
The phenomenon of sleep eating illustrates that even when we feel fast asleep, we
may be “half-awake”—and capable of putting together some unusual late-night snacks,
including buttered cigarettes, salt sandwiches, and raw bacon. The maker of Ambien has
noted this unusual side effect on the label of the drug. Even more alarming than sleep
eating is sleep driving (Saul, 2006). Sleep experts agree that sleep driving while taking
Ambien is rare and extreme but plausible.
F o r i n d i v i d u a l s w h o a r e b a t t l i n g p e r s i s t e n t i n s o m n i a , a d r u g t h a t p r o v i d e s a g o o d
night’s rest may be worth the risk of these unusual side effects. Furthermore, no one
should abruptly stop taking any medication without consulting a physician.
N I G H T M A R E S A N D N I G H T T E R R O R S A nightmare is a frightening dream
that awakens a dreamer from REM sleep (Germain, 2012). The nightmare’s content invari-
ably involves danger—the dreamer is chased, robbed, or thrown off a cliff. Nightmares
are common. Most of us have had them, especially as young children. Nightmares peak
at 3 to 6 years of age and then decline, although the average college student experiences
four to eight nightmares a year (Hartmann, 1993). Reported increases in nightmares or
worsening nightmares are often associated with an increase in life stressors such as the
loss of a relative or a job and con icts with others.
A night terror features sudden arousal from sleep and intense
fear. Night terrors are accompanied by a number of physiological
reactions, such as rapid heart rate and breathing, loud screams,
heavy perspiration, and movement (Zadra & Pilon, 2012). Night
terrors, which peak at 5 to 7 years of age, are less common than
nightmares, and unlike nightmares, they occur during slow-wave,
non-REM sleep.
N A R C O L E P S Y T h e d i s o r d e r narcolepsy involves the sudden,
overpowering urge to sleep. The urge is so uncontrollable that the
person may fall asleep while talking or standing up. Narcoleptics
immediately enter REM sleep rather than progressing through the rst
four sleep stages (Siegel, 2011). Individuals with narcolepsy are often
very tired during the day. Narcolepsy can be triggered by extreme
emotional reactions, such as surprise, laughter, excitement, and anger.
The disorder appears to involve problems with the hypothalamus and
amygdala (Brabec & others, 2011). Although narcolepsy usually
emerges in adulthood, signs of the problem may be evident in child-
hood (Nevsimalova, 2009).
Used by permission of CartoonStock,
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Sleep and Dreams // 143
S L E E P A P N E A Sleep apnea is a sleep disorder in which individuals stop breathing
because the windpipe fails to open or because brain processes involved in respiration fail
to work properly. People with sleep apnea experience numerous brief awakenings
during the night so that they can breathe better, although they usually are not
aware of their awakened state. During the day, these people may feel sleepy
because they were deprived of sleep at night. A common sign of sleep apnea
is loud snoring, punctuated by silence (the apnea).
S l e e p a p n e a a f f e c t s a p p r o x i m a t e l y 1 8 m i l l i o n A m e r i c a n s ( H o & B r a s s ,
2011). The disorder is most common among infants and adults over the age
of 65. Sleep apnea also occurs more frequently among obese individuals, men,
and individuals with large necks and recessed chins (Kotsis & others, 2010).
Untreated sleep apnea can cause high blood pressure, stroke, and sexual dys-
function (Ho & Brass, 2011; P a r a t i , L o m b a r d i , & N a r k i e w i c z , 2 0 0 7 ) . I n a d d i -
tion, the daytime sleepiness caused by sleep apnea can result in accidents,
lost productivity, and relationship problems (Hartenbaum & others, 2006).
Sleep apnea is commonly treated by weight-loss programs, side sleeping,
propping the head on a pillow, or wearing a device (called a CPAP, for con-
tinuous positive airway pressure) that sends pressurized air through a mask
that prevents the airway from collapsing.
Sleep apnea may also be a factor in sudden infant death syndrome (SIDS) ,
the unexpected sleep-related death of an infant less than one year old. SIDS
is typically con rmed with an autopsy that reveals no speci c cause of death
(Byard & Krous, 2004; Fifer & Myers, 2002). It is common for infants to
have short pauses in their breathing during sleep, but for some infants frequent
sleep apnea may be a sign of problems in regulating arousal (Kato & others,
2003). There is evidence that infants who die of SIDS in fact experience multiple
episodes of sleep apnea in the days before the fatal event (Kahn & others, 1992). One
possible explanation for SIDS is an abnormality in the brain stem areas responsible for
arousal (Kinney, 2009). Such an abnormality may lead to sleep apnea, which in turn
might worsen the brain stem damage, ultimately leading to death.
Have you ever dreamed that you left your long-term romantic partner for a former lover?
If so, did you tell your partner about that dream? Probably not. However, you would
have likely wondered about the dream’s meaning, and if so you would not be alone.
Since the dawn of language, human beings have attributed great meaning to dreams. As
early as 5000 b.c.e. , Babylonians recorded and interpreted their dreams on clay tablets.
Egyptians built temples in honor of Serapis, the god of dreams. Dreams are described
at length in more than 70 passages in the Bible. Psychologists have also examined this
fascinating topic.
Sigmund Freud put great stock in dreams as a key to our unconscious minds. He
believed that dreams (even nightmares) symbolize unconscious wishes and that analysis
of dream symbols could uncover our hidden desires. Freud distinguished between a
dream’s manifest content and its latent content. Manifest content is the dream’s surface
content, which contains dream symbols that disguise the dream’s true meaning; latent
content is the dream’s hidden content, its unconscious—and true—meaning. For exam-
ple, if a person had a dream about riding on a train and talking with a friend, the train
ride would be the dream’s manifest content. Freud thought that this manifest content
expresses a wish in disguised form. To get to the latent or true meaning of the dream,
the person would have to analyze the dream images. In our example, the dreamer would
be asked to think of all the things that come to mind when the person thinks of a train,
the friend, and so forth. By following these associations to the objects in the manifest
content, the latent content of the dream could be brought to light. Artists have sometimes
manifest content
According to Freud, the
surface content of a dream,
containing dream symbols
that disguise the dream’s
true meaning.
latent content
According to
Freud, a dream’s
hidden content;
its unconscious
and true meaning.
Keep a sleep journal for several
nights. Compare your sleep patterns
with those described in the text. Do
you have a sleep debt? If so, which
stages of sleep are you most likely
missing? Does a good night’s sleep
affect your behavior? Keep a record
of your mood and energy levels after
a short night’s sleep and then after
you have had at least 8 hours of
sleep in one night. What changes
do you notice, and how do they
compare with the changes predicted
by research on sleep deprivation
described in the chapter?
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144 // CHAPTER 4 // States of Consciousness
incorporated the symbolic world of dreaming
in their work (Figure 4.8).
M o r e r e c e n t l y , p s y c h o l o g i s t s h a v e a p p r o a c h e d
dreams not as expressions of unconscious
wishes but as mental events that come from
various sources. Research has revealed a great
deal about the nature of dreams (De Koninck,
2012). A common misconception is that dreams
are typically bizarre or strange, but many stud-
ies of thousands of dreams, collected from indi-
viduals in sleep labs and sleeping at home, have
shown that dreams generally are not especially
strange. Instead, research shows that dreams are
often very similar to waking life (Domhoff,
2007; Schredl, 2009; Schwartz, 2010).
A l t h o u g h s o m e a s p e c t s o f d r e a m s a r e
unusual, dreams often are no more bizarre than
a typical fairy tale, TV show episode, or movie
plot. Dreams do generally contain more nega-
tive emotion than everyday life; and certainly
some unlikely characters, including dead peo-
ple, sometimes show up in dreams.
There is also no evidence that dreams pro-
vide opportunities for problem solving or
advice on handling life’s dif culties. We may
dream about a problem we are dealing with, but
we typically nd the solution while we are
awake and thinking about the dream, not during
the dream itself (Domhoff, 2007). There is also
no evidence that people who remember their
dreams are better off than those who do not
(Blagrove & Akehurst, 2000).
So, if the typical dream involves doing ordinary things, what are dreams? The most
prominent theories that attempt to explain dreams are cognitive theory and activation-
synthesis theory.
C O G N I T I V E T H E O R Y O F D R E A M I N G T h e cognitive theory of
dreaming p r o p o s e s t h a t w e c a n u n d e r s t a n d d r e a m i n g b y a p p l y i n g t h e s a m e
cognitive concepts we use in studying the waking mind. The theory rests on the
idea that dreams are essentially subconscious cognitive processing. Dreaming
involves information processing and memory. Indeed, thinking during dreams
appears to be very similar to thinking in waking life (Domhoff, 2011).
In the cognitive theory of dreaming, there is little or no search for the hidden, symbolic
content of dreams that Freud sought. Instead, dreams are viewed as dramatizations of gen-
eral life concerns that are similar to relaxed daydreams. Even very unusual aspects
of dreams, such as odd activities, strange images, and sudden scene shifts,
can be understood as metaphorically related to a person’s preoccupa-
tions while awake (Domhoff, 2007, 2011; Zadra & Dom-
hoff, 2010). The cognitive theory also ties the brain activity
that occurs during dreams to the activity that occurs
during waking life. The term default
network r e f e r s t o a c o l l e c -
tion of neurons that are
active during mind wan-
dering and daydreaming,
essentially whenever we
are not focused on a task.
cognitive theory
of dreaming
Theory propos-
ing that we can
dreaming by ap-
plying the same
cognitive con-
cepts we use
in studying the
waking mind.
FIGURE 4.8 Artist’s Portrayal of a Dream Marc Chagall
(1887–1985) painted a world of dreams in I and the Village (1911).
Wh y m i g h t w e b e l i e v e
dr eams ar e st r anger t han
they really are? Which type of
dr eams ar e we mor e l i kel y t o
remember? Why?
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Sleep and Dreams // 145
Research suggests that dreaming during sleep may also emerge from the activity of this
network (Domhoff, 2011).
The cognitive theory of dreaming strongly argues that dreams should be viewed as a
kind of mental simulation that is very similar in content to our everyday waking thoughts.
The same themes that occupy us in our waking life occupy our dreams. This perspective
on dreams contrasts with activation-synthesis theory of dreams.
A C T I V A T I O N - S Y N T H E S I S T H E O R Y A c c o r d i n g t o activation-synthesis theory ,
dreaming occurs when the cerebral cortex synthesizes neural signals generated from activity
in the lower part of the brain. Dreams result from the brain’s attempts to nd logic in ran-
dom brain activity that occurs during sleep (J. A. Hobson, 1999; A. Hobson & Voss, 2011).
When we are awake and alert, our conscious experience tends to be driven by exter-
nal s timuli, all those things we see, hear, and respond to. During sleep, according to
activation-synthesis theory, conscious experience is driven by internally generated stim-
uli that have no apparent behavioral consequence. A key source of such internal stimula-
tion is spontaneous neural activity in the brain stem (J. A. Hobson, 2000). Some of the
neural activity that produces dreams comes from external sensory experiences. If a re
truck with sirens blaring drives past your house, you might nd yourself dreaming about
an emergency. Many of us have had the experience of incorporating the sound of our
alarm clock going off in an early morning dream.
Supporters of activation-synthesis theory have suggested that neural
networks in other areas of the forebrain play a signi cant role in dreaming
(J. A. Hobson, Pace-Schott, & Stickgold, 2000). Speci cally, they believe
that the same regions of the forebrain that are involved in certain waking
behaviors also function in particular aspects of dreaming (Lu & others,
2006). As levels of neurotransmitters rise and fall during the stages of sleep,
some neural networks are activated and others shut down. Random neural ring
in various areas of the brain leads to dreams that are the brain’s attempts to make
sense of the activity. So, ring in the primary motor and sensory areas of the forebrain
might be re ected in a dream of running and feeling wind on your face. From the
activation-synthesis perspective, our nervous system is cycling through various activi-
ties, and our consciousness is simply along for the ride (J. A. Hobson, 2000, 2004).
Dreams are merely a ashy sideshow, not the main event (Hooper & Teresi, 1993).
Indeed, one activation-synthesis theorist has referred to dreams as so much “cognitive
trash” (J. A. Hobson, 2002, p. 23).
Like all dream theories, activation-synthesis theory has its critics. A key criticism is
that damage to the brain stem does not necessarily reduce dreaming, suggesting that this
area of the brain is not the only starting point for dreaming. Furthermore, life experiences
stimulate and shape dreaming more than activation-synthesis theory acknowledges
(Domhoff, 2007; Malcolm-Smith & others, 2008).
activation-synthesis theory
Theory that dreaming
occurs when the cerebral
cortex synthesizes neural
signals generated from ac-
tivity in the lower brain and
that dreams result from the
brain’s attempts to fi nd logic
in random brain activity that
occurs during sleep.
You may have not i ced
how i nt er n al st at es i nf l u en c e
your dr eams i f you have ever been
ver y t hi r s t y whi l e s l eeping,
and you dr eam t hat you
get a gl as s of wat er .
1. The brain structure that is responsible
for the synchronization of circadian
rhythm is the
A. cerebral cortex.
B. hypothalamus.
C. reticular formation.
D. suprachiasmatic nucleus.
2. Immediately entering REM sleep is a
symptom of
A. sleep apnea.
B. narcolepsy.
C. night terrors.
D. somnambulism.
3. The brain waves that are active when we
are awake and focused are
A. alpha waves.
B. beta waves.
C. delta waves.
D. theta waves.
APPLY IT! 4. Bobby and Jill have a
friendly competition going in their psychol-
ogy class. Both have spent several hours
studying for the final exam over the last
few weeks of school. The night before the
final, Bobby declares that he is going to
pull an all-nighter, adding 12 full hours to
his study time compared to Jill. Altogether,
Jill studies 23 hours for the exam, while
Bobby studies 35 hours. All other things
being equal, who is likely to do better on
the exam and why?
A. Bobby will do better because he studied
much more than Jill did.
B. Jill will do better because she studied a
great deal and has the benefit of a good
night’s sleep, allowing her memory for
course material to consolidate.
C. Bobby will do better because even
though he missed some hours of sleep,
his memories will be fresher than Jill’s.
D. Jill will do better because Bobby is
probably overprepared—35 hours is too
long to study anything.
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146 // CHAPTER 4 // States of Consciousness
One way that people seek to alter their own consciousness is through the use of psycho-
active drugs. In fact, illicit drug use is a global problem. According to the United Nations
Of ce on Drugs and Crime (UNODC), more than 200 million people worldwide use
drugs each year (UNODC, 2011). Among those, approximately 27 million individuals
are characterized as problem drug users—individuals whose drug habit interferes with
their ability to engage in work and social relationships (UNODC, 2011).
Drug consumption among youth is a special concern because of its links to problems
such as unsafe sex, sexually transmitted infections, unplanned pregnancy, depression, and
school-related dif culties (Eaton & others, 2008; UNODC, 2011). The use of drugs
among U.S. secondary school students declined in the 1980s but began to increase in
the early 1990s (Johnston & others, 2012). Then in the late 1990s and early 2000s, the
proportion of secondary school students reporting the use of any illicit drug again
declined (Johnston & others, 2012).
D r u g u s e b y U . S . h i g h s c h o o l s e n i o r s s i n c e 1 9 7 5 a n d b y U . S . e i g h t h - a n d t e n t h -
graders since 1991 has been tracked in a national survey called Monitoring the Future
(Johnston & others, 2012). Figure 4.9 shows the trends for these groups in these periods
(Johnston & others, 2012). The most notable declines in adolescent drug use in the
twenty- rst century have occurred for marijuana, LSD, Ecstasy, steroids, and cigarettes.
However, marijuana use by adolescents increased from 2007 to 2010. The United States
still has the highest rate of adolescent drug use of any industrialized nation (Johnston &
others, 2012).
Uses of Psychoactive Drugs
Psychoactive drugs act on the nervous system to alter consciousness, modify percep-
tions, and change moods. Some people use psychoactive drugs as a way to deal with
life’s dif culties. Drinking, smoking, and taking drugs reduce tension, relieve boredom
and fatigue, and help people to escape from the harsh realities of life. Some people use
drugs because they are curious about their effects.
The use of psychoactive drugs, whether it is to cope with problems or just for fun,
can carry a high price tag. These include losing track of one’s responsibilities, problems
psychoactive drugs
Drugs that act on the
nervous system to alter
consciousness, modify
perceptions, and change
Psychoactive Drugs
Percentage of students who reported
illicit drug use in the last 12 months
1975 1980 1985 1990 20001995 2005 2012
12th grade
10th grade
8th grade
FIGURE 4.9 Trends in Drug Use by U.S. Eighth-, Tenth-,
and Twelfth-Grade Students This graph shows the percentage
of U.S. eighth-, tenth-, and twelfth-grade students who reported having
taken an illicit drug in the last 12 months from 1991 to 2012 (for
eighth- and tenth-graders) and from 1975 to 2012 (for twelfth-graders)
(Johnston & others, 2012). > Note that data were not collected from
eighth- and tenth-graders until 1991. Why do you think these groups
were added? > After the mid-1990s, all age groups show a similar
pattern of decline in drug use. Why might this pattern have occurred
in all three groups? > What are the implications of using self-reports
from children and adolescents in this research? Do you think each
group would be similarly likely to be honest, to over-report, or to
under-report their drug use?
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Psychoactive Drugs // 147
Vent r al t egment al
ar ea and nucl eus accumbens ar e
mo u t h f u l s , b u t t h e s e a r e a s o f t h e b r a i n
ar e vi t al t o t he exper i ence of pl eas ur e.
Re membe r t he se st r uct ur e s; t he y wi l l
come up agai n and agai n.
FIGURE 4.10 The Brain’s Reward Pathway for Psychoactive
Drugs The ventral tegmental area (VTA) and nucleus accumbens (NAc) are important
locations in the reward pathway for psychoactive drugs. Information travels from the VTA to
the NAc and then up to the prefrontal cortex. The VTA is located in the midbrain just above
the pons, and the NAc is located in the forebrain just beneath the prefrontal cortex.
Prefrontal cortex
Nucleus accumbens (NAc)
Ventral tegmental area (VTA)
in the workplace and in relationships, drug depen-
dence, and increased risk for serious, sometimes
fatal diseases (Fields, 2013; Zilney, 2011). For
example, drinking alcohol may initially help
people relax and forget about their worries.
If, however, they turn more and more to
alcohol to escape reality, they may develop
a dependence that can destroy relation-
ships, careers, and their bodies.
C o n t i n u e d u s e o f p s y c h o a c t i v e d r u g s
leads to tolerance , t h e n e e d t o t a k e i n c r e a s -
ing amounts of a drug to get the same
effect (Goldberg, 2010). For example, the
rst time someone takes 5 milligrams of the
tranquilizer Valium, the person feels very
relaxed. However, after taking the pill every
day for six months, the individual may need to
consume twice as much to achieve the same calming
Continuing drug use can also result in
physical dependence , the physiological
need for a drug that causes unpleasant
withdrawal symptoms such as physical
pain and a craving for the drug when it is
discontinued. Psychological dependence
is the strong desire to repeat the use of a drug for emotional reasons, such as a
feeling of well-being and reduction of stress. Experts on drug abuse use the
term addiction t o d e s c r i b e e i t h e r a p h y s i c a l o r p s y c h o l o g i c a l d e p e n d e n c e ,
or both, on the drug (Hales, 2011).
H o w d o e s t h e b r a i n b e c o m e a d d i c t e d ? P s y c h o a c t i v e d r u g s i n c r e a s e
dopamine levels in the brain’s reward pathways (De Biasi & Dani, 2011).
This reward pathway is located in the ventral tegmental area (VTA) and
nucleus accumbens (NAc) (Figure 4.10). Only the limbic and prefrontal
areas of the brain are directly activated by dopamine, which comes from the
VTA (Koob, 2006). Although different drugs have different mechanisms of action,
each drug increases the activity of the reward pathway by increasing dopamine transmis-
sion. As we will see throughout this book, the neurotransmitter dopamine plays a vital
role in the experience of rewards.
Types of Psychoactive Drugs
Three main categories of psychoactive drugs are depressants, stimulants, and
hallucinogens. All have the potential to cause health or behavior problems or
both. To evaluate whether you abuse drugs, see Figure 4.11.
D E P R E S S A N T S Depressants a r e p s y c h o a c t i v e d r u g s t h a t s l o w d o w n
mental and physical activity. Among the most widely used depressants are
alcohol, barbiturates, tranquilizers, and opiates.
A l c o h o l Alcohol is a powerful drug. It acts on the body primarily as a
depressant and slows down the brain’s activities (Hales, 2011). This effect
might seem surprising, as people who tend to be inhibited may begin to talk,
dance, and socialize after a few drinks. However, people “loosen up after
a few drinks because the brain areas involved in inhibition and judgment
The need to
take increasing
amounts of a
drug to get the
same effect.
The physiological
need for a drug
that causes un-
pleasant with-
drawal symptoms
such as physical
pain and a
craving for the
drug when it is
The strong desire
to repeat the use
of a drug for
emotional rea-
sons, such as a
feeling of well-
being and reduc-
tion of stress.
Either a physical
or a psychologi-
cal dependence,
or both, on a
drugs that slow
down mental and
physical activity.
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148 // CHAPTER 4 // States of Consciousness
FIGURE 4.11 Do You Abuse
Drugs? Take this short quiz to see if your
use of drugs and alcohol might be a cause for
Respond yes or no to the following items:
I have gotten into problems because of using drugs.
Using alcohol or other drugs has made my college life
unhappy at times.
Drinking alcohol or taking other drugs has been a factor
in my losing a job.
Drinking alcohol or taking other drugs has interfered with
my studying for exams.
Drinking alcohol or taking drugs has jeopardized my
academic performance.
My ambition is not as strong since I've been drinking a
lot or taking drugs.
Drinking or taking drugs has caused me to have
difficulty sleeping.
I have felt remorse after drinking or taking drugs.
I crave a drink or other drugs at a definite time of the day.
I want a drink or other drug in the morning.
I have had a complete or partial loss of memory as a
result of drinking or using other drugs.
Drinking or using other drugs is affecting my reputation.
I have been in the hospital or another institution
because of my drinking or taking drugs.
Yes No
College students who responded yes to items similar to these on the Rutgers
Collegiate Abuse Screening Test were more likely to be substance abusers than
those who answered no. If you responded yes to just 1 of the 13 items on this
screening test, consider going to your college health or counseling center for
further screening.
slow down. As people drink more, their inhibitions decrease even further, and their
judgment becomes increasingly impaired. Activities that require intellectual function-
ing and motor skills, such as driving, become harder to perform. Eventually the
drinker falls asleep. With extreme intoxication, the person may lapse into a coma
and die. Figure 4.12 illustrates alcohols main effects on the body.
The effects of alcohol vary from person to person. Factors in this variation are
body weight, the amount of alcohol consumed, individual differences in the way
body metabolizes alcohol, and the presence or absence of tolerance (Sparling &
Redican, 2012). Men and women differ in terms of the intoxicating effects of alcohol.
Because of differences in body fat as well as stomach enzymes, women are likely to
be more strongly affected by alcohol than men.
How does alcohol affect the brain? Like other psychoactive drugs, alcohol goes to
the VTA and the NAc (Hopf & others, 2010). Alcohol also increases the concentration
of the neurotransmitter gamma aminobutyric acid (GABA), which is widely dis-
tributed in many brain areas, including the cerebral cortex, cerebellum, hip-
pocampus, amygdala, and nucleus accumbens (Tateno & Robinson, 2011).
Researchers believe that the frontal cortex holds a memory of the pleasure
involved in prior alcohol use and contributes to continued drinking. Alcohol
consumption also may affect the areas of the frontal cortex involved in judg-
ment and impulse control (Bouchard, Brown, & Nadeau, 2012). It is further
believed that the basal ganglia, which are involved in compulsive behaviors, may lead
to a greater demand for alcohol, regardless of reason and consequences (Brink, 2001).
After caffeine, alcohol is the most widely used drug in the United States. As many
as two-thirds of U.S. adults drink beer, wine, or liquor at least occasionally, and in one
survey approximately 30 percent reported drinking more than ve drinks at one sitting
Somet i mes f r i e nds
think someone who is
danger ous l y dr unk j ust needs
to sleep it off. Drinking to
the point of passing out is
a s ympt om of al cohol
poi soni ng. Cal l 911.
Thi s expl ai n s how
get t i ng t he nex t dr i nk can become
mo r e i mp o r t a n t t h a n a n y t h i n g
el se i n t he per s on s l i f e.
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Psychoactive Drugs // 149
at least once in the last year (National Center for Health Statistics, 2005). The common
use of alcohol is related to other serious problems, including death and injury from driv-
ing while drinking (Levinthal, 2010; National Highway Traf c Safety Administration,
2007). Research has also found a link between alcohol and violence and aggression
(Gallagher & Parrott, 2010). More than 60 percent of homicides involve alcohol use by
the offender or the victim, and 65 percent of aggressive sexual acts against women are
associated with alcohol consumption by the offender.
A special concern is the high rate of alcohol use by U.S. secondary school and
college students (Chen & Jacobson, 2012; Chung & others, 2012). In the Monitoring
the Future survey, 40 percent of high school seniors surveyed reported consuming
alcohol in the last 30 days in 2011 (Johnston & others, 2012). The good news: That
percentage (40) represents a decline from 54 percent in 1991. In the most recent sur-
vey, 25 percent of the high school seniors surveyed had engaged in binge drinking
( h a v i n g ve or more drinks in a row) at least once during the previous month, down
from 34 percent in 1997.
Binge drinking often increases during the rst two years of college, and, as Figure
4.13 shows, it can take its toll on students (Little eld & Sher, 2010). In a Monitoring
the Future survey of college students, 41 percent reported engaging in binge drinking in
the last two weeks (49 percent of males, 33 percent of females) (Johnston & others,
2008). In a national survey of drinking patterns on college campuses, almost half of the
binge drinkers reported problems such as missed classes, injuries, trouble with police,
and unprotected sex (Wechsler & others, 2000, 2002). Binge-drinking college students
were 11 times more likely to fall behind in school, 10 times more likely to drive after
drinking, and twice as likely to have unprotected sex as college students who did not
binge drink. Many emerging adults, however, decrease their alcohol use as they assume
Alcohol flows into the stomach and
small intestine; excess alcohol in the
stomach causes vomiting
Blood flow to the skin
increases, causing loss of body
heat, flushing, and sweating
Liver breaks down
0.5–1 ounce of alcohol
Vision is blurred
Speech is impaired
Sensation and perceptions are diminished
Inhibitions, judgment, and intellectual
functions are impaired
Urine output increases in kidneys;
more urine passes from the body
than is typical
Heart rate and blood
pressure increase
Motor coordination and reflexes
are impaired; balance is disturbed
FIGURE 4.12 The Physiological and Behavioral Effects of Alcohol Alcohol has a powerful impact throughout the body. Its effects touch
everything from the operation of the nervous, circulatory, and digestive systems to sensation, perception, motor coordination, and intellectual functioning.
Binge Drinking and the
Adolescent Brain
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150 // CHAPTER 4 // States of Consciousness
adult responsibilities such as a permanent job, marriage or cohabitation, and parenthood
(Chen & Jacobson, 2012).
Alcoholism is a disorder that involves long-term, repeated, uncontrolled, compulsive,
and excessive use of alcoholic beverages and that impairs the drinker’s health and social
relationships. Approximately 18 million people in the United States are alcoholics
(MedlinePlus, 2012). A longitudinal study linked early onset of drinking to later alcohol
problems (Hingson, Heeren, & Winter, 2006). Individuals who began drinking alcohol
before 14 years of age were more likely to become alcohol dependent than their coun-
terparts who began drinking alcohol at 21 years of age or older.
One in nine individuals who drink continues down the path to alcoholism. Those who
do are disproportionately related to alcoholics; family studies consistently nd a high
frequency of alcoholism in the close biological relatives of alcoholics (Buscemi & Turchi,
2011; Sintov & others, 2010). A possible explanation is that the brains of people genet-
ically predisposed to alcoholism may be unable to produce adequate dopamine, the neu-
rotransmitter that can make us feel pleasure (Landgren & others, 2011). For these
individuals, alcohol may increase dopamine concentration and resulting pleasure to the
point where it leads to addiction (Meyer, Meshul, & Phillips, 2009).
Like other psychological characteristics, though, alcoholism is not all about nature:
Nurture matters too. Indeed, research shows that experience plays a role in alcohol-
ism (Kendler, Gardner, & Dick, 2011). Many alcoholics do not have close relatives
whoare alcoholics (Duncan & others, 2006), a nding that points to environmental
i n uences.
What does it take to stop alcoholism? About one-third of alcoholics recover whether
they are in a treatment program or not. This nding came from a long-term study of 700
individuals (Vaillant, 2003). George Vaillant followed the participants for over 60 years,
and he formulated the so-called one-third rule for alcoholism: By age 65, one-third are
dead or in terrible shape; one-third are still trying to beat their addiction; and one-third
Disorder that
involves long-
term, repeated,
compulsive, and
excessive use of
alcoholic bever-
ages and that im-
pairs the drinker’s
health and social
The Troubles Frequent Binge Drinkers Crea te . . .
For Themselves
Percent of those surveyed who
admitted having had the problem
Missed class 61
Forgot where they were or what
they did 54
Engaged in unplanned sex 41
Got hurt 23
Had unprotected sex 22
Damaged property 22
Got into trouble with campus or
local police 11
Had five or more alcohol-related
problems in school year 47
Frequent binge drinkers were defined
as those who had at least four or five
drinks at one time on at least three
occasions in the previous two weeks.
For Others
Percent of those surveyed who
had been affected by drinkers
Had study or sleep interrupted 68
Had to care for drunken student 54
Were insulted or humiliated 34
Experienced unwanted sexual
advances 26
Had serious argument 20
Had property damaged 15
Were pushed or assaulted 13
Had at least one of the above
problems 87
These figures are from colleges where
at least 50 percent of students are binge
FIGURE 4.13 Consequences of Binge Drinking
Binge drinking has wide-ranging negative consequences.
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Psychoactive Drugs // 151
Han d y Sur v i v al
Ti p s : N e v e r s h a r e p r e s c r i p t i o n
dr ugs. Never t ake s omeone
el se’ s pr esc r i pt i on dr ugs.
Never mi x pr e scr i pt i on
dr ugs wi t h al cohol .
are abstinent or drinking only socially. Vaillant found that recovery from alcoholism was
predicted by (1) having a strong negative experience with drinking, such as a serious
medical emergency; (2) nding a substitute dependency, such as meditation, exercise, or
overeating (which has its own adverse health effects); (3) developing new, positive rela-
tionships; and (4) joining a support group such as Alcoholics Anonymous.
Barbiturates Barbiturates, such as Nembutal and Seconal, are depressant drugs
that decrease central nervous system activity. Physicians once widely prescribed bar-
biturates as sleep aids. In heavy dosages, they can lead to impaired memory and
decision making. When combined with alcohol (for example, sleeping pills taken
after a night of binge drinking), barbiturates can be lethal. Heavy doses of bar-
biturates by themselves can cause death. For this reason, barbiturates are the drug
most often used in suicide attempts. Abrupt withdrawal can produce seizures.
Because of the addictive potential and relative ease of toxic overdose, barbiturates
have largely been replaced by tranquilizers in the treatment of insomnia.
Tranquilizers Tranquilizers, such as Valium and Xanax, are depressant drugs that
reduce anxiety and induce relaxation. In small doses tranquilizers can induce a feeling
of calm; higher doses can lead to drowsiness and confusion. Tolerance for tranquilizers
can develop within a few weeks of usage, and these drugs are addictive. Widely pre-
scribed in the United States to calm anxious individuals, tranquilizers can produce with-
drawal symptoms when use is stopped. Prescription tranquilizers were part of the lethal
cocktail of drugs that, in 2008, ended the life of actor Heath Ledger, who played the
Joker in the Batman lm The Dark Knight .
Opiates Narcotics, or opiates , consist of opium and its derivatives and depress the
central nervous system’s activity. These drugs are used as powerful painkillers. The most
common opiate drugs—morphine and heroin—affect synapses in the brain that use
endorphins as their neurotransmitter. When these drugs leave the brain, the affected
synapses become understimulated. For several hours after taking an opiate, the person
feels euphoric and pain-free and has an increased appetite for food and sex. Opiates are
highly addictive, and users experience craving and painful withdrawal when the drug
becomes unavailable.
Opiate addiction can also raise the risk of exposure to HIV, the virus that causes AIDS.
Most heroin addicts inject the drug intravenously. When they share needles without
sterilizing them, one infected addict can transmit HIV to others.
S T I M U L A N T S Stimulants are psychoactive drugs that increase the central nervous
system’s activity. The most widely used stimulants are caffeine, nicotine,
amphetamines, and cocaine.
C a f f e i n e O f t e n o v e r l o o k e d a s a d r u g , c a f f e i n e i s t h e w o r l d s m o s t
widely used psychoactive drug. Caffeine is a stimulant and a natural com-
ponent of the plants that are the sources of coffee, tea, and cola drinks. Caffeine
also is present in chocolate, in many nonprescription medications, and in energy
drinks such as Red Bull. People often perceive the stimulating effects of caffeine
as bene cial for boosting energy and alertness, but some experience unpleasant
side effects.
Caffeinism refers to overindulgence in caffeine. It is characterized by mood changes,
anxiety, and sleep disruption. Caffeinism often develops in people who drink ve or
more cups of coffee (at least 500 milligrams) each day. Common symptoms are insom-
nia, irritability, headaches, ringing ears, dry mouth, increased blood pressure, and diges-
tive problems (Hogan, Hornick, & Bouchoux, 2002).
Caffeine affects the brain’s pleasure centers, so it is not surprising that it is dif cult
to kick the caffeine habit. When individuals who regularly consume caffeinated beverages
remove caffeine from their diet, they typically experience headaches, lethargy, apathy,
drugs, such as
Nembutal and
Seconal, that de-
crease central
nervous system
Depressant drugs, such as
Valium and Xanax, that
reduce anxiety and induce
Opium and its derivatives;
narcotic drugs that depress
the central nervous system’s
activity and eliminate pain.
drugs, including
caffeine, nicotine,
and cocaine, that
increase the
central nervous
system’s activity.
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152 // CHAPTER 4 // States of Consciousness
Attention and alertness improve
At high levels, muscles become
more relaxed and anxiety and
anger may be reduced; pleasant
feelings induce the smoker to
smoke more
In a pregnant woman,
nicotine freely passes
through the placenta
wall into amniotic fluid
Smoker loses appetite
for carbohydrates
Circulation to
Heart rate and
blood pressure
FIGURE 4.14 The Physiological and Behavioral Effects of
Nicotine Smoking has many physiological and behavioral effects. Highly addictive,
nicotine delivers pleasant feelings that make the smoker smoke more, but tobacco
consumption poses very serious health risks to the individual.
and concentration dif culties. These symptoms of
withdrawal are usually mild and subside after
several days.
N i c o t i n e N i c o t i n e i s t h e m a i n p s y -
choactive ingredient in all forms of
smoking and smokeless tobacco. Even
with all the publicity given to the enor-
mous health risks posed by tobacco,
we sometimes overlook the highly
addictive nature of nicotine. Nicotine
stimulates the brains reward centers by
raising dopamine levels. Behavioral
effects of nicotine include improved atten-
tion and alertness, reduced anger and
a n x i e t y , a n d pain relief (Knott & others, 2006).
Figure 4.14 shows the main effects of nicotine on
the body.
Tolerance develops for nicotine both in the long
run and on a daily basis, so that cigarettes smoked
later in the day have less effect than those smoked
earlier. Withdrawal from nicotine often quickly pro-
Cigarette advertisements have long linked cigarette
smoking with healthy, attractive people and the good life.
Go on a caffeine hunt. Check out the
ingredient lists on your favorite
beverages, snacks, and painkillers.
Which of these contain caffeine? You
might be surprised by how much
caffeine you consume every day
without even knowing it.
duces strong, unpleasant symp-
toms such as irritability, craving,
inability to focus, sleep distur-
bance, and increased appetite.
Withdrawal symptoms can persist
for months or longer.
Tobacco poses a much larger
threat to public health than illegal
drugs. According to the Centers for
Disease Control and Prevention
(2011), tobacco is involved in one in
every ve deaths in the United States,
more than the total number killed by
AIDS, alcohol, motor vehicles, homi-
cide, illegal drugs, and suicide com-
bined. Today there are approximately 1
billion smokers globally, and estimates
are that by 2030, another 1 billion
youth will have started to smoke
(United Nations World Youth Report,
2005). Worldwide, approximately 25
percent of people between the ages of
15 and 65 smoke (UNODC, 2011). In
2010, there were approximately
46.6 million adult smokers in the
United States (Centers for Disease
Control and Prevention, 2011).
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Psychoactive Drugs // 153
Cigarette smoking is decreasing among
both adolescents and college students. In the
national Monitoring the Future survey by the
Institute of Social Research, the percentage
of U.S. adolescents who are current cigarette
smokers continued to decline in 2011 (John-
ston & others, 2012). Cigarette smoking
peaked in 1996 and 1997 and then decreased
13 to 18 percent, depending on grade level,
from 1998 to 2011 (Figure 4.15).
The drop in cigarette use by U.S. youth
may have several sources, including higher
cigarette prices, less tobacco advertising
reaching adolescents, more antismoking adver-
tisements, and more negative publicity about
the tobacco industry than before. Increasingly,
adolescents report perceiving cigarette smok-
ing as dangerous, disapprove of it, are less
accepting of being around smokers, and prefer
to date nonsmokers (Johnston & others, 2012).
With respect to college students and young
adults, smoking has shown a smaller decline
than adolescent and adult smoking (Johnston
& others, 2012).
I n s u m , c i g a r e t t e s m o k i n g a p p e a r s t o b e g e n e r a l l y o n t h e d e c l i n e . M o s t s m o k e r s r e c -
ognize the serious health risks of smoking and wish they could quit. Chapter 14 explores
the dif culty of giving up smoking and gives strategies for quitting.
Amphetamines Amphetamines, or “uppers,are stimulant drugs that people use to
boost energy, stay awake, or lose weight. Often prescribed in the form of diet pills, these
drugs increase the release of dopamine, which enhances the user’s activity level and
pleasurable feelings.
Perhaps the most insidious illicit drug for contemporary society is crystal metham-
phetamine, or crystal meth. Smoked, injected, or swallowed, crystal meth (also called
“crank” or “tina”) is a synthetic stimulant that causes a powerful feeling of euphoria,
particularly the rst time it is ingested. Meth is made using household products such as
battery acid, cold medicine, drain cleaner, and kitty litter, and its effects have been dev-
astating, notably in rural areas of the United States.
Crystal meth releases enormous amounts of dopamine in the brain, producing intense
feelings of pleasure. The drug is highly addictive. The extreme high of crystal meth
leads to a severe “come down” experience that is associated with strong cravings.
Crystal meth also damages dopamine receptors, so that a person can be chasing
a high his or her brain can no longer produce. Because an individual’s very rst
experience with crystal meth can lead to ruinous consequences, the Drug Enforce-
ment Agency has started a website, designed by and targeted at teenagers, www., to share the hard facts of the horri c effects of this and other illicit
Cocaine Cocaine is an illegal drug that comes from the coca plant, native to Bolivia
and Peru. Cocaine is either snorted or injected in the form of crystals or powder. Used
this way, cocaine oods the bloodstream rapidly, producing a rush of euphoric feelings
that lasts for about 15 to 30 minutes. Because the rush depletes the brain’s supply of the
neurotransmitters dopamine, serotonin, and norepinephrine, an agitated, depressed mood
usually follows as the drug’s effects decline. Figure 4.16 shows how cocaine affects
dopamine levels in the brain.
Percentage of U.S. secondary school students
who smoked cigarettes in the past 30 days
1976 1980 1984 1988 20001992 1996 2004 2008 2012
12th grade
10th grade
8th grade
FIGURE 4.15 Trends in Cigarette Smoking by U.S.
Secondary School Students Fortunately, cigarette smoking by U.S.
high school students is on the decline.
Se r i ousl y, don t
try itnot even once.
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154 // CHAPTER 4 // States of Consciousness
Normal dopamine reuptake
Dopamine reuptake blocked by cocaine
Cocaine and
Neurotransmitters Cocaine concentrates
in areas of the brain that are rich in dopamine
synapses such as the ventral tegmental area (VTA)
and the nucleus accumbens (NAc). (Top) What
happens in normal reuptake. The transmitting
neuron releases dopamine, which stimulates the re-
ceiving neuron by binding to its receptor sites. After
binding occurs, dopamine is carried back intothe
transmitting neuron for later release. (Bottom) What
happens when cocaine is present in the synapse.
Cocaine binds to the uptake pumps and prevents
them from removing dopamine from the synapse.
The result is that more dopamine collects in
the synapse, and more dopamine receptors are
Crack is a potent form of cocaine, consisting of chips of pure cocaine that
are usually smoked. Scientists believe that crack is one of the most addictive sub-
stances known. Treatment of cocaine addiction is dif cult (Ahmadi & others, 2009).
Cocaine’s addictive properties are so strong that, six months after treatment, more
than 50 percent of abusers return to the drug, a statistic that highlights the importance
of prevention.
M D M A ( E c s t a s y ) M D M A c a l l e d E c s t a s y , X , o r X T C i s a n i l l e g a l s y n t h e t i c
drug with both stimulant and hallucinogenic properties. People have called Ecstasy an
“empathogen” because under its in uence, users tend to feel warm bonds with others.
MDMA produces its effects by releasing serotonin, dopamine, and norepinephrine. The
effects of the drug on serotonin are particularly problematic. MDMA depletes the brain
of this important neurotransmitter, producing lingering feelings of listlessness that often
continue for days after use (National Institute on Drug Abuse, 2009).
MDMA impairs memory and cognitive processing. Heavy users of Ecstasy show
cognitive de cits that persist even two years after they begin to abstain (Rogers & oth-
ers, 2009; Ward, Hall, & Haslam, 2006). Because MDMA destroys axons that release
serotonin, repeated use might lead to susceptibility to depression (Cowan, Roberts, &
Joers, 2008).
Hallucinogens are psychoactive drugs that modify a person’s
perceptual experiences and produce visual images that are not real. Hallucinogens are
also called psychedelic (from the Greek meaning “mind-revealing”) drugs. Marijuana has
a mild hallucinogenic effect; LSD, a stronger one.
M a r i j u a n a
Marijuana is the dried leaves and owers of the hemp plant Cannabis
sativa, which originated in Central Asia but is now grown in most parts of the
world. The plant’s dried resin is known as hashish. The active ingredient in mari-
juana is THC (delta-9-tetrahydrocannabinol). Unlike other psychoactive drugs,
drugs that modify
a person’s per-
ceptual experi-
ences and
produce visual
images that are
not real.
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Psychoactive Drugs // 155
THC does not affect a speci c neurotransmitter. Rather, marijuana disrupts the
membranes of neurons and affects the functioning of a variety of neurotransmitters
and hormones.
The physical effects of marijuana include increased pulse rate and blood pressure,
reddening of the eyes, coughing, and dry mouth. Psychological effects include a mix-
ture of excitatory, depressive, and mildly hallucinatory characteristics that make it
dif cult to classify the drug. Marijuana can trigger spontaneous unrelated ideas;
distorted perceptions of time and place; increased sensitivity to sounds, tastes, smells,
and colors; and erratic verbal behavior. The drug can also impair attention and memory.
Further, when used daily in large amounts, marijuana can alter sperm count and change
hormonal cycles (Close, Roberts, & Berger, 1990). In addition, pregnant women should
avoid using marijuana. Recent research indicates a number of negative birth outcomes
for the offspring of mothers who used marijuana during pregnancy, such as increased
admission to the neonatal intensive care unit (Hayatbakhsh & others, 2012), lower
intelligence at age 6 (Goldschmidt & others, 2008), and elevated risk of using marijuana
at age 14.
M a r i j u a n a i s t h e i l l e g a l d r u g m o s t w i d e l y u s e d b y h i g h s c h o o l s t u d e n t s . I n t h e M o n -
ito r ing the Future survey, 46 percent of U.S. high school seniors said they had tried
marijuana in their lifetime, and 23 percent reported that they had used marijuana in the
last 30 days (Johnston & others, 2012). One concern about adolescents’ use of marijuana
is that the drug might be a gateway to the use of other more serious illicit substances.
Although there is a correlational relationship between using marijuana and using other
illicit drugs, evidence for the notion that marijuana use leads to the use of other drugs
is mixed (Tarter & others, 2006).
LSD L S D ( l y s e r g i c a c i d d i e t h y l a m i d e ) i s a h a l l u c i n o g e n t h a t e v e n i n l o w d o s e s p r o -
duces striking perceptual changes. Objects change their shapes and glow. Colors become
kaleidoscopic and astonishing images unfold. LSD-induced images are sometimes plea-
surable and sometimes grotesque. LSD can also in uence a user’s sense of time so that
brief glances at objects are experienced as deep, penetrating, and lengthy examinations,
and minutes turn into hours or even days. A bad LSD trip can trigger extreme anxiety,
paranoia, and suicidal or homicidal impulses.
LSD’s effects on the body can include dizzi-
ness, nausea, and tremors. LSD acts primarily
on the neurotransmitter serotonin in the brain,
though it also can affect dopamine (Gonzalez-
Maeso & Sealfon, 2009). Emotional and cogni-
tive effects may include rapid mood swings and
impaired attention and memory. The use of LSD
peaked in the 1960s and 1970s, and its con-
sumption has been decreasing in the twenty- rst
century (Johnston & others, 2012).
S o m e o f t h e p s y c h o a c t i v e d r u g s w e h a v e s u r -
veyed have been considered useful for medical
purposes. Consequently, there is ongoing public
controversy over the legalization of drugs, such
as marijuana, for medical purposes. The debate
over medical marijuana illustrates the con icts
that can erupt over the possibility of an illicit
drug’s legalization. In the late 1970s, it became
apparent that marijuana could be used as a
treatment for glaucoma (a condition of abnor-
mally high uid pressure within the eyeball)
because cannabis reduces pressure in the eye
(American Academy of Ophthalmology, 2003).
Medical marijuana is now legal in 17 states and the District of Columbia,
and in 2009, Attorney General Eric Holder announced an end to federal
raids on medical marijuana facilities unless these enterprises violated
both state and federal law.
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156 // CHAPTER 4 // States of Consciousness
Relaxation, depressed brain
activity, slowed behavior,
reduced inhibitions
Relaxation, sleep
Relaxation, slowed
Euphoric feelings,
drowsiness, nausea
Disorientation, loss of
consciousness, even
death at high blood-
alcohol levels
Breathing difculty,
coma, possible death
Breathing difculty,
coma, possible death
Convulsions, coma,
possible death
Strong hallucinations, distorted
time perception
Euphoric feelings, relaxation,
mild hallucinations, time
distortion, attention and
memory impairment
Severe mental
disturbance, loss of
contact with reality
Fatigue, disoriented
Increased alertness,
excitability; decreased fatigue,
Increased alertness,
excitability, euphoric feelings;
decreased fatigue, irritability
Mild amphetamine and
hallucinogenic effects; high
body temperature and
dehydration; sense of
well-being and social
Alertness and sense of
well-being followed by fatigue
Stimulation, stress reduction,
followed by fatigue, anger
Extreme irritability,
feelings of persecu-
tion, convulsions
Extreme irritability,
feelings of persecu-
tion, convulsions,
cardiac arrest,
possible death
Brain damage,
especially memory
and thinking
Nervousness, anxiety,
disturbed sleep
disturbed sleep
Accidents, brain
damage, liver disease,
heart disease, ulcers,
birth defects
Accidents, coma,
possible death
Accidents, coma,
possible death
Accidents, infectious
diseases such as AIDS
Accidents, respiratory
Insomnia, hypertension,
malnutrition, possible
Insomnia, hypertension,
malnutrition, possible
problems; death