Chapter 6: Consciousness





What Is Consciousness?

Two Dimensions of Consciousness: Wakefulness and Awareness

            Minimal Consciousness

            Moderate Consciousness

            Full Consciousness

Attention: Focusing Consciousness

Selective Attention

Sustained Attention   

Psychology in the Real World:  Hazards of Cell Phone-Induced Driver Distraction

Training Consciousness: Meditation

            Meditation and Conscious Experience

            Mediation Training and the Brain

Sleeping and Dreaming


Sleep and Circadian Rhythms

Sleep and the Brain

The Development of Sleep over the Life Span

The Function of Sleep

Sleep Deprivation and Sleep Debt

Disorders of Sleep


Psychoanalytic Theory

Biological Theory

            Cognitive Theory


Breaking New Ground: The Cognitive Neuroscience of Hypnosis

Altering Consciousness with Drugs














Making Connections: Brain Injury Revisited

Chapter Review





  • Consciousness is an awareness of one’s surroundings and thoughts.
  • It is our experience of a moment as we move through it but it also involves the capacity to take in and process information briefly before sending it to specialized areas for further use or storage.
  • CONNECTION: How much information can we hold in consciousness briefly before it is processed further, stored, or forgotten (see Chapter 7)? 
  • The various sensory elements are brought together in the global workspace of consciousness (Baars, 1997; Baars & Franklin, 2003).



    • Wakefulness refers the degree of alertness, resulting from whether a person is awake or asleep.
    • Awareness refers to the monitoring of information from the environment and from one’s own thoughts (Brown & Ryan, 2003).
  • Variations in consciousness can be explained in terms of degrees of wakefulness and awareness (Laureys, 2007).
    • A person in a coma is very low in wakefulness and awareness.
    • Mindfulness is characterized by high wakefulness and awareness.


Minimal Consciousness

  • Minimal consciousness refers to states when people are barely awake or aware.
  • A person in a coma has his/her eyes closed and is unresponsive. 
  • A person in a vegetative state might have his/her eyes open but he/she is otherwise unresponsive.  It can be thought of as “wakefulness without awareness” (Bernat, 2006).
    • In one study, researchers asked a young woman in a vegetative state to imagine a few things, such as walking through her house and playing tennis while they scanned her brain using an fMRI. Her brain showed activation in the same areas as did the brains of people who were conscious and asked to imagine the same things.
  • Those in a minimally conscious state are largely unresponsive but have begun to show some deliberate movements (Laureys, 2007).


Moderate Consciousness

  • Freud used the term preconscious to refer to information that is potentially accessible but is not currently in awareness. 
    • The tip-of-the-tongue phenomenon—the feeling that you know something (like the movie you saw a particular actress in) but you can’t quite put your finger on it—is a good example.
    • Another term for this stage is moderate consciousness.
  • Sleep and dreaming are moderately conscious states in which one can be roused by important sounds but can ignore others. Most sensations of the outer world are still not perceived.


Full Consciousness

  • This is the state we spend most of our waking lives – relatively alert and aware. Alertness does, however, vary throughout the day.
    • When people are awake but understimulated and not very aroused by their environment, they may be bored.
    • When they are awake but have the impulse and need to sleep, they are drowsy.
  • A flow state occurs when we get so involved in what we are doing that we lose a sense of time and where we are.
  • Mindfulness is a heightened awareness of the present moment, which can be applied to events in one’s environment and events in one’s own mind.
    • People vary considerably in how mindful they are naturally but there are also skills one can acquire to increase their mindfulness.



  • Attention is the limited capacity to process information that is under conscious control (Styles, 2006).


Selective Attention

    • Selective attention is the ability to focus awareness on specific features in the environment while ignoring others.
    • CONNECTION: The mental illness schizophrenia is marked by an inability to selectively filter out and attend to only the most relevant information from the world. For more discussion of other qualities of schizophrenia, see Chapter 16.
    • In dichotic listening tasks, a participant received one message in one ear and another message in the other ear, and the participant was told to pay attention to just one ear (the attended ear). Recall is generally better for the attended ear.
    • If the material presented to the unattended ear is meaningful in some way, it can make its way into consciousness (Treisman, 1964).
      • For example, the cocktail party effect is the ability to filter out auditory stimuli and then to refocus attention when you hear your name.
    • Selective attention creates gaps in attention and perception because we focus so much on certain things that we are blind to other things.
      • For example, researchers showed people a video of two basketball teams with one team dressed in white T-shirts and the other in black shirts. They asked participants simply to count the number of times the players on the team wearing white T-shirts passed the ball. About half the participants were dumbfounded to learn afterward that they completely missed seeing a person dressed in a gorilla suit walk into the game, pauses for a second to beat his chest, and then walk off screen.
      • This phenomenon by which we fail to notice unexpected objects in our surroundings is referred to as inattentional blindness.
    • The perceptual load model states that we do not notice potential distracters when a primary task consumes all of our attentional capacity (Lavie, Hirst, De Fockert, & Viding, 2004). When a primary task is minimally demanding, however, distracters can capture our awareness.
    • Likewise, conscious attention occurs when neurons from many distinct brain regions work together.


Sustained Attention

    • Sustained attention is the ability to maintain focused awareness on a target.
    • Sustained attention has been studied using the Continuous Performance Test (CPT).
      • Participants are asked to detect one letter among other letters shown very rapidly, one by one on a computer screen.
      • Most people cannot perform well on CPT tasks for more than about 15 minutes, and their accuracy in detecting targets declines considerably after 5 to 7 minutes (Nuechterlein & Parasuraman, 1983; Parasuraman, 1998).


Psychology in the Real World:  Hazards of Cell Phone-Induced Driver Distraction

  • People generally acknowledge the potential hazards of cell phone use while driving, yet the practice is widespread.
  • In the view of psychologists, phone conversations while driving are distracting, even when the hands are free.  With such distraction, performance declines and safety is compromised.
    • A recent analysis of studies looking at cell phone use during driving showed that the dangers to driving are similar for hand-held and hands-free phones (Horrey & Wickens, 2006).
  • Strayer and Drews (2007) did several experiments with people in a driving simulator. Some of the participants wore a hands-free headset and engaged in a conversation while doing a driving task; the others had no cell phone and simply drove.
    • In the first study, several objects were inserted into the driving scene that drivers were not told they’d need to attend to. Later, they tested them on recognition of these objects. People talking on cell a phone saw half as many objects as those not on the phone.
    • In another study, the researchers varied the objects inserted into the driving scene in terms of how important they were for driving safety. Later, when drivers were tested on memory for seeing the objects, they were just as likely to miss safety-relevant objects as safety-irrelevant objects.
  • An fMRI study of people driving in a simulator showed that activity in the parietal lobe decreased when people listened to sentences while driving, whereas activity in areas associated with language processing increased. Their driving was also worse.
  • At least two studies have shown that people talking with a friend in the car perform better in a simulator than those on the phone.



  • Meditation refers to a wide variety of practices that people use to calm the mind, stabilize concentration, focus attention, and enhance awareness of the present moment.
  • Concentration meditation involves sitting still for long periods of time, staying relaxed yet alert, and focusing their attention on the breath moving in and out of one’s mouth and nose.
  • Mindfulness meditation techniques encourage attention to the details of momentary experience, such as all the thoughts, feelings, and sensation available in the moment at hand (Baer, 2003).
  • CONNECTIONS: Every time you make a memory or learn something new, you change your brain by strengthening synaptic connections or growing new neurons (see Chapter 8).


Meditation and Conscious Experience

·         Mindfulness meditation training appears to enhance well-being, decrease depression, and improve physical health (Anderson, Lau, Segal, & Bishop, 2008; Kabat-Zinn et al., 1998; Teasdale et al., 2000).

·         Because meditation enhances awareness of the present moment, it also improves attention.

o       It improves selective attention and orienting by actively (and voluntarily) applying awareness to detail.


Meditation Training and the Brain

·         Meditation training has been shown to significantly increase activity in the left frontal cortex; an area associated with positive emotions.

o       Nature-Nurture Pointer: Meditation training is correlated with changes in brain function and structure.

o       CONNECTION: How does random assignment work to make groups more equivalent in research? (See Chapter 2.)

·         Meditation practice may alter the physical structure of the brain. 

o       Researchers used MRI to measure the thickness of various regions of the cortex in experienced practitioners of insight meditation and found that meditators’ brains were thicker than the comparison group’s in cortical areas associated with attention, sensitivity to bodily sensations, and the processing of external sensory information.  The amount of meditation experience was positively correlated with cortical thickness in some of these areas.

§         Insight meditation emphasizes the development of awareness of the workings of one’s body and mind.





·         The sleeping brain is very active, but it is only partially processing information from the outside world.

·         The two essential features of sleep are 1) that there is a “wall” between the outside world and the conscious mind; and, 2) the “wall” can immediately come down.  That is, the mind filters out important information (e.g., an alarm clock) from relatively less important information (e.g., a roommate’s phone conversation).

Sleep and Circadian Rhythms

o       Circadian rhythms are the variations in physiological processes that cycle within an approximately 24-hour period.

o       Three different bodily activities each fluctuate on a circadian cycle: body temperature, the hormone melatonin, and alertness.

o       Jet lag occurs when a person’s day is shortened or elongated by travel across time zones, thereby throwing the circadian cycle off its usual track.

o       The suprachiasmatic nucleus, or SCN (a part of the hypothalamus), acts as the brain’s clock.

§         Neurons in the SCN connect to the retina and optic nerve. Exposure to light in the morning stimulates neurons in SCN to “reset.”  These neurons then send inhibitory signals to the pineal gland, which decreases how much melatonin (a hormone important in relaxation and drowsiness) is released (Itri, Michel, Waschek, & Colwell, 2004).

§         In the evening, the SCN neurons become less active, allowing the secretion of melatonin, which increases relaxation.

Sleep and the Brain

o       The brain is very active during sleep and each state of wakefulness, and sleep has its own pattern of brain activity.

§         When awake, brain activity shows beta waves rapid but low-energy waves.

§         When we are relaxed and drowsy our brain activity switches to alpha waves, which are slower and slightly higher energy waves.

o       The second major form of sleep is called non-REM, which has relatively few eye movements, and those that occur are slow rather than fast.

§         Rapid eye movements (REM) are the quick movements of the eye that occur during sleep, thought to mark phases of dreaming.

o       There are four stages of non-REM sleep:

§         Stage 1: Brain waves change to theta waves – slower and lower energy than alpha waves. This is when we first fall asleep.  It is a light sleep and not much stimulation is needed to awaken us.

§         Stage 2:  Starts about 5 to 7 minutes after entering Stage 1.  There are two unique markers of Stage 2: 1) theta waves now show short periods of extremely fast and somewhat higher energy wave activity called sleep spindles; and, 2) there are sudden high energy waves called K-complexes.

§         Stage 3: There are four stages of non-REM sleep, each marked by unique brain wave patterns. This stage starts with theta waves with some higher energy delta waves. As this stage progresses, there are more delta waves and fewer sleep spindles and K-complexes.

§         Stage 4: Occurs when sleep spindles and K-complexes disappear completely.  This is the deepest stage of sleep.

o       Shortly after entering Stage 4 sleep, sleep spindles and K-complexes of Stage 3 return, followed by the theta waves of Stages 2 and 1.

o       After returning to Stage 1, the eyes begin to move rapidly underneath the eyelids, indicating the entry into REM. The night’s first episode of REM sleep lasts for 8-10 minutes before the process begins again.

§         With each progressive cycle, the non-REM periods are shorter and the REM periods longer (Dement, 1999).

§         In sum, each night adults move through about 4 to 6 different cycles of non-REM and REM sleep.

§         Each cycle lasts roughly 90 minutes.

o       Full-blown dreams are less common during non-REM than REM sleep, but they do occur regularly during non-REM stages. The dreams are different, though, in that they are less detailed, less active, and are more like regular thinking (Bulkeley, 1997; Foulkes, 1996; Kahan, 2001).

The Development of Sleep Over the Life Span

o       Newborns spend more time in REM sleep than in non-REM sleep. In humans, REM sleep declines rapidly over the life span.

§         The percentage of total sleep that is REM stays close to 50% for the first three months of life.

§         By 8 months it falls to 33%.

§         By age one it drops to about 28%.

o       The amount of REM sleep over the life span corresponds to the degree of brain plasticity and neural growth (Dement, 1999).

o       CONNECTIONS: There are critical periods in sensory, language, and cognitive development – meaning that if proper stimulation and experience does not occur during the peak times our brain is most sensitive to learning, our sensory, language, and cognitive abilities are forever stunted. See Chapters 3 and 5 and 9 for more on critical and sensitive periods and the brain.

The Function of Sleep

o       Sleep supports three major restorative processes: neural growth, memory consolidation, and protection against cellular damage.

§         First, sleep deprivation inhibits the growth of new neurons.

§         Second, sleep helps us learn and remember things (Karni et al., 1994; Payne & Nadel, 2004; Stickgold & Walker, 2007). Task learning is replayed in the brain during sleep, and then this brain practice helps performance the next day.

§         Third, sleep appears to fight cell damage. Sleep aids cell function by triggering the production of enzymes that fight cell damage (Ramanathan, Gulyani, Nienhuis, & Siegel, 2002) and slows the metabolism itself thereby slowing the rate of cellular damage (Wouters-Adriaens & Westerterp, 2006).

o       Nature-Nurture Pointer:  Sleep increases neuronal growth and helps us remember things.

o       CONNECTION: If sleep is a memory aid, is it possible to learn while we sleep by listening to a recording? Or is this a myth? Chapter 7 explores ways to increase recall of text and lecture material.

Sleep Deprivation and Sleep Debt

o       Forty percent of U.S. adults are sleep-deprived (Dement, 1999).

o       The typical adult gets about 6 hours and 40 minutes of sleep on week days and 7 hours and 25 minutes on weekends (National Sleep Foundation, 2008).

o       Sleep debt refers to how much sleep our brains owe our bodies. If you get 2 hours less sleep one night, then you owe your body 2 hours of additional sleep the next night (or within a few days). If it is not paid back in sleep then it is paid back in daytime drowsiness, use of stimulants such as caffeine and nicotine, lack of focused attention, and impaired learning and memory.

§         Accidents are the most serious type of payback. As many as 30% of all automobile accidents can be attributed to drowsiness (Dement, 1999).

Disorders of Sleep

o       About 20% of people in the U.S. suffer from sleep disorders (Dement, 1999).

o       Insomnia is taking more than 20 minutes to fall asleep, having trouble staying asleep, and/or not feeling rested after a night’s sleep for two or more consecutive weeks (Krystal, 2005).

§         About 15 to 20% of U.S. adults suffer from insomnia (Pearson, Johnson, & Nahin, 2006).

§         Possible causes of insomnia include restless leg syndrome, erratic hours, medical conditions, iron deficiency, psychiatric disorders such as depression, and excessive use of alcohol (Dement, 1999; Roehrs, Zorick, & Roth, 2000).

§         Drug treatments for insomnia, such as Ambien, work by increasing the effects of GABA (gamma-aminobutyric acid), the neurotransmitter that decreases central nervous system activity.

§         CONNECTION: The functions of GABA, glutamate, and other neurotransmitters are discussed in Chapter 3.

o       A person with sleep apnea literally stops breathing for a short amount of time.

§         This is commonly masked as loud snoring.  It is most common in men and obese people.

§         These people seldom fall into deep and REM sleep, and as such are consistently sleep-deprived and often suffer from insomnia.

§         The condition can be fatal, as its sufferers are at increased risk for automobile accidents, diabetes, and heart disease.

§         Treatments for apnea aim to reduce throat blockage, by weight loss, surgery, or devices that keep the throat open.

·         The most effective treatment is use of a device during sleep that pushes air into the throat at high enough pressure to keep the throat open (American Sleep Apnea Association, 2006).

o       Sleepwalking occurs when a person gets out of bed during sleep, usually during the first third of the sleep cycle, and engages in activities that normally occur during wakefulness.

§         People who sleepwalk are difficult to rouse and do not remember having been up after waking in the morning.

§         Because sleepwalking occurs during non-REM sleep, the sleepwalker is not likely to be acting out a dream.

o       Hypersomnia exists when a person sleeps more than 10 hours a day for two weeks or more.

§         It involves strong urges to nap throughout the day, often in inappropriate times like during meals or in the middle of conversations.

§         It can be caused by other sleep disorders, brain injury, or depression.



·         Dreams are the succession of images, thoughts, and feelings we experience while asleep. The succession of images is loosely connected by unusual associations and not well recalled afterward.

·         Most people dream numerous times each night.

Psychoanalytic Theory

o       Freud argued that impulses, thoughts, feelings, and drives that threaten the waking mind are released in distorted and disguised form by the sleeping mind.

o       Dreams operate on two distinct levels of consciousness:

§         Manifest level:  This is the dream that is consciously recalled after waking up.

§         Latent level:  This is the deeper, unconscious level, where the true meaning of a dream lies.

o       CONNECTION: Free association is another therapeutic technique used in Freudian psychoanalysis (see Chapter 17).

Biological Theory

o       AIM theory (Activation, Input, and Mode) is one of the most popular biological theories for dreaming. 

§         Activation is the dimension that involves the amount of neural activation and ranges from low to high activation. 

§         Input is the extent to which stimulation is internal or external. It ranges from the inside to the outside world.

§         Mode consists of a dimension that ranges from logical (wakeful) to loose-illogical (dreaming) states.

§         REM sleep is highly active, internal, and loose, and therefore occupies the lower front right portion of the cube.

Cognitive Theory

o       Dreams are not that different from everyday thinking.

o       Lucid dreaming is the ability to know when you are dreaming and therefore being in control of the events and outcomes of the dreams.

o       Some can reflect on and evaluate their experiences while dreaming.

o       Non-REM dreaming is closer to waking thought than REM sleep dreaming.



·         Hypnosis is a state of mind that occurs in compliance with instructions and is characterized by focused attention, suggestibility, absorption, lack of voluntary control over behavior, and suspension of critical faculties of mind (Raz & Shapiro, 2002; Stewart, 2005).

·         People vary considerably in the degree to which they can be hypnotized, largely because we are not equally suggestible.

·         Clinical hypnosis should not be confused with stage techniques.

·         Numerous studies support the effectiveness of hypnosis for pain relief during childbirth, dental procedures, wart removal, and surgery.

·         Hypnosis may help treat smoking, nausea, and vomiting related to chemotherapy, and anxiety associated with certain medical procedures (Lang et al., 2006; Montgomery, DuHamel, & Redd, 2000; Patterson, 2004; Stewart, 2005).


Breaking New Ground: The Cognitive Neuroscience of Hypnosis

·         See separate section for detailed explanation.



·         Psychoactive drugs are naturally occurring or synthesized substances that reliably produce qualitative changes in conscious experience.

·         Psychoactive drug use is universal among humans. Drugs are used to to aid in spiritual practice, to improve health, to explore the self, to regulate mood, to escape boredom and despair, to enhance sensory experience, to stimulate artistic creativity and performance, and to promote social interaction (Weil & Rosen, 1998).

·         Problems arise when people develop a physical dependence on the drug to maintain normal function and to cope with the challenges of daily life.

o       If you develop a tolerance to a drug then you need more and more of the drug to get the effect that you desire from it.

o       Withdrawal symptoms are the adverse effects people experience if they stop using it.

·         Psychological dependence occurs when people compulsively use a substance for various reasons, such as to alleviate boredom, to regulate mood, or to cope with the challenges of everyday life.

·         Addiction results from sustained use and physical or psychological dependence on a substance (Taylor, 2006).



·         Depressants decrease or slow down central nervous system activity.

·         In low doses, these drugs generally calm the body and mind.

·         In high doses, they can slow down heart rate and brain activity to dangerously low levels.


o       Alcohol is the most widely used depressant.

o       The amount of alcohol in the bloodstream is the common measure of inebriation known as Blood Alcohol Level (BAL). BAL is measured in milligrams of alcohol per 100 milliliters of blood (milligrams %), so a BAL of .10 means that one tenth of 1%, or 1/1000th of one’s blood content, is alcohol (0.08 BAL is currently the legal limit for driving in all states in the U.S.).

o       The more alcohol a person consumes, the more obvious the depressant effects become, sometimes leading to blackouts.

§         Alcohol has “stimulating” effects at first (you feel loose and relaxed) because alcohol suppresses the higher social regulatory functions of the cerebral cortex, thereby lowering inhibitions.

§         Over time, heavy drinking (more than 5 drinks per day) leads to fat accumulation and blocked blood flow in the liver.

§         Chronic alcoholism is one of the most common causes of cirrhosis, the accumulation of nonfunctional scar tissue in the liver.

§         Nature-Nurture Pointer: Excessive drinking can shrink the brain.

·         With long periods of heavy drinking, the brain actually shrinks. With abstinence, the brain recovers much of its lost volume, especially in the first month of abstinence (Gazdzinski, Durazzo, & Meyerhoff, 2005; Kubota et al., 2001).

·         This risk is greater for adolescents than adults.

o       CONNECTIONS:  What is special about the adolescent brain? (See Chapter 5.)

o       Binge drinking is usually defined as at least 5 drinks in a row for men and 4 for women (Jackson, 2008; Wechsler et al., 2002).

§         About 40% of college students binge drink.

§         One of the more serious risks of binge drinking is blacking out – loss of memory of specific events.

o       Mild to moderate alcohol intake (no more than 2 drinks a day) provides protective effects for cardiovascular health.


o       Sedatives (such as barbituates and benzodiazepines) create a feeling of stupor similar to that of alcohol intoxication. They slow the heart rate, relax skeletal muscles, and tranquilize the mind.

o       Medically, barbiturates (e.g., secobarbital [Seconalâ], pentobarbital [Nembutalâ], diazepam [Valiumâ], and chlordiazepoxide [Libriumâ]) are used in anesthesia to calm people down during certain medical procedures and as a temporary sleeping aid.

o       All these drugs have the potential for both physical and psychological dependence, can be lethal at high doses, and should be used only under strict medical supervision.


o       Opioids (also called narcotics) are all drugs derived from opium or chemicals similar to opium.

o       Such drugs may be derived from natural sources (like morphine), partially synthetic (like heroin), or entirely synthetic (such as codeine).

§         Modern synthetic opioids include oxycodone (Percosetâ or Percodanâ), which is prescribed for moderate to severe pain, and hydrocodone (Vicodinâ), which is prescribed for milder pain.

o       Opioids depress central nervous system activity, slowing heart rate, respiration, digestion, and suppressing the cough center.

o       Opioids have been used for centuries as pain relievers because they make use of the body’s own naturally occurring opioid systems.

§         Endorphins are opioid-like proteins that bind to opioid receptors in the brain and act as natural painkillers.  

o       Stronger opioids (opium, morphine, and heroin) produce feelings of overwhelming bliss, euphoria, and bodily relaxation. This is why opioids have a high potential for abuse.

o       Many people inadvertently develop an addiction to opioids while being treated for chronic pain. Some newer therapeutic opioids, such as buprenorphine, can be taken at higher doses with less risk of overdose (Johnson, Fudala, & Payne, 2005).



·         Stimulants activate the nervous system.


o       Coffee, tea, cocoa, energy drinks, and certain other soft drinks have caffeine. In fact, it is the world’s most commonly consumed psychoactive drug.

o       The effects of mild to moderate caffeine intake are increased alertness, increased heart rate, loss of motor coordination, insomnia, and nervousness.

o       Too much caffeine can make people jittery and anxious.

o       If regular caffeine users stop consuming caffeine, they can experience significant withdrawal symptoms, the most common of which is headache. Other withdrawal symptoms are fatigue and decreased energy, depressed mood, and difficulty concentrating (Juliano & Griffiths, 2004).


o       Nicotine is the active drug in tobacco.

o       Smoking tobacco puts nicotine in the bloodstream immediately, and within 8 seconds of inhalation it reaches the brain.

o       Nicotine increases heart rate and rate of respiration, and it creates a feeling of arousal, although many users report that cigarettes calm them down.

o       Over time, the cardiovascular arousal associated with nicotine use increases the risk of high blood pressure and heart disease.

o       Nicotine is extremely addictive. It creates high tolerance, physical dependence, and unpleasant withdrawal symptoms. In fact, it is harder to kick a nicotine addiction than a heroin addiction.

o       There are many known health risks of smoking: it reduces life expectancy on average by 10 years, increases the risk for lung cancer more than ten fold, and triples the risk of death from heart disease in both men and women (CDC, 2001; Doll, Peto, Boreham, & Sutherland, 2004). It is also linked to leukemia, cataracts, pneumonia, and cancers of the cervix, kidney, pancreas, and stomach.

o       Tobacco smoke contains many cancer-causing agents that trigger severe damage to DNA and can inhibit DNA repair in lung cells.

o       Tobacco smoke also contains carbon monoxide, a toxic substance that displaces oxygen in the bloodstream, so tissues get less oxygen than they need. Carbon monoxide from smoking also makes people look older than they are.


o       South American Indians chew coca leaves for their stimulant and digestion-aiding properties, and the most notable component in the coca plant is cocaine.

o       When snorted, cocaine increases heart rate and produces a short-lived, but intense, rush of euphoria. It also can lead to a sense of invulnerability and power. 

o       Physiologically, cocaine induces a sense of exhilaration by increasing the availability of the neurotransmitters dopamine and serotonin (Mateo, Budygin, John, & Jones, 2004). 

o       The high cocaine brings on is very short, which explains why people abuse it. 

o       If someone is free-basing, he or she is injecting cocaine.

o       Crack is a form of cocaine that is sold on the streets in pellets.

o       Cocaine increases heart rate and causes irregular heart beat, increases risk of heart attack, and, occasionally, leads to death (Weil & Rosen, 1998).


o       Amphetamines are synthetically produced compounds that produce long-lasting excitation of the sympathetic nervous system.

o       Three main forms (all of which are pills): methamphetamine (Meth), dextroamphetamine (Dexedrine), and amphetamine sulphate (Benzedrine or “speed”).

o       Most people who abuse amphetamines get them from health care providers.

§         They are prescribed as appetite suppressants and treat symptoms of ADHD.

o       Amphetamines cause increased heart rate, increased motivation, and excited mood.

§         Short-term effects may include insomnia, stomach distress, headaches, decreased libido, and difficulty concentrating.

§         Long-term use can lead to severe depression, paranoia, loss of control over one’s behavior, and, in some cases, amphetamine psychosis, a condition marked by hallucinations.

o       Symptoms of withdrawal from chronic amphetamine use include fatigue, anxiety and depression, hunger, overeating, and disordered thought and behavior.


o       The psychoactive drug MDMA, also known as ecstasy, is both a stimulant and mild hallucinogen.

§         It is chemically similar to methamphetamines and the active ingredient in hallucinogenic mushrooms.

o       It is sometimes called “the love drug” because it produces feelings of euphoria, warmth, and connectedness with others.

o       The dangers of MDMA include increased risk of depression with repeated use, slower processing times on cognitive tasks, and greater impulsivity (Halpern et al., 2004).

o       Long-term effects include persistent mental deficits, low mood, and serotonin deficiencies in certain areas of the brain (Thomasius et al., 2006).




·         Hallucinogens create distorted perceptions of reality, ranging from mild to extreme. They can also alter thought and mood.


o       Marijuana comes from the blossoms and leaves of the Cannabis sativa plant. The active ingredient in cannabis is tetrahydrocannibinol (THC).

o       Marijuana alters mood to create euphoria and changes perception, especially one’s perception of time and food. Hallucinations are rare but are more common when it is eaten.

o       Marijuana is not addictive but, with habitual use, people do develop cravings. People can become psychologically dependent on marijuana, too.

o       Regular marijuana smoking increases the likelihood of a variety of respiratory illnesses, can cause immune system impairment, and appears to lead to memory problems (Kanayama et al., 2004; Tashkin et al., 2002).

o       Regular marijuana use is common in adolescents who later develop schizophrenia.

o       Marijuana can prevent and treat nausea so it has been prescribed for those suffering from chemotherapy-related nausea or the wasting syndrome of AIDS.

o       Marijuana and its derivatives can also be helpful in treating pain.

LSD: lysergic acid diethylamide-25

o       LSD (or “acid”) is a synthesized form of lysergic acid which is derived from ergot (grain fungus).

o       Ingesting LSD causes dramatic changes in conscious experience, including altered visual perceptions, enhanced color perception, hallucinations, and synesthesia (“seeing” sounds or “hearing” visual images).

o       LSD increases the levels of dopamine and serotonin. Serotonin activity, in turn, increases the excitatory neurotransmitter glutamate.

o       Side effects include increased body temperature, increased blood pressure, insomnia, and psychosis-like symptoms in some people.

§         For some people LSD use leads to bad trips (panic and negative experiences).

§         For other people, however, it can have an opposite effect and lead to very profound, life-altering experiences (Strassman, 1984; Weil & Rosen, 1998).


Making Connections: Brain Injury and Consciousness

·         See separate section for detailed explanation.





AIM: three biologically based dimensions of consciousness – Activation, Input, and Mode.

alpha waves: pattern of brain activity when one is relaxed and drowsy; slower, higher-energy waves than beta waves.

attention: the limited capacity to process information that is under conscious control.

awareness: aspect of consciousness that is the monitoring of information from the environment and from one’s own thoughts.

beta waves: pattern of brain activity when one is awake; a rapid, low-energy wave.

circadian rhythms: the variations in physiological processes that cycle within an approximately  24-hour period, including the sleep-wake cycle.

coma: a state of consciousness in which the eyes are closed and the person is unresponsive and unarousable; a much more severe and longer-lasting loss of consciousness than fainting.

consciousness: an awareness of one’s surroundings and of what’s in one’s mind at a given moment; includes aspects of being awake and aware.

delta waves: type of brain activity that dominates Stage 2 sleep; higher energy than theta waves.

depressants: substances that decrease or slow down central nervous system activity.

dreams: images, thoughts, and feelings experienced during sleep.

endocannabinoids: natural, marijuana-like substances produced by the body.

hallucinogens: substances that create distorted perceptions of reality, ranging from mild to extreme.

hypersomnia: sleep difficulty characterized by sleeping more than 10 hours a day for 2 weeks or more; includes urge to nap during inappropriate times.

hypnosis: a state characterized by focused attention, suggestibility, absorption, lack of voluntary control over behavior, and suspension of critical faculties; occurs when instructed by someone trained in hypnosis; may be therapeutic.

insomnia: a sleep difficulty characterized by difficulty falling and staying asleep, as well as not feeling rested.

latent level: Freud’s unconscious level of dreams; their meaning is found at this level.

manifest level: Freud’s surface level of dreams, recalled upon waking.

meditation: practices that people use to calm the mind, stabilize concentration, focus attention, and enhance awareness of the present moment.

mindfulness: a heightened awareness of the present moment, whether of events in one’s environment or in one’s own mind.

minimal consciousness: states or phases of consciousness when people are barely awake or aware.

narcolepsy: sleep disorder characterized by excessive daytime sleepiness and weakness in facial and limb muscles.

non-REM: form of sleep with few eye movements, which are slow rather than fast.

psychoactive drugs: naturally occurring or synthesized substances that, when ingested or otherwise taken into the body, reliably produce qualitative changes in conscious experience.

rapid eye movements (REM): quick movements of the eye that occur during sleep, thought to mark phases of dreaming.

selective attention: the ability to focus awareness on specific features in the environment while ignoring others.

sleep apnea: a sleep difficulty that results from temporary blockage of the air passage.

sleepwalking: a sleep difficulty characterized by activities occurring during non-REM sleep that usually occur when one is awake, such as walking and eating.

stimulants: substances that activate the nervous system.

Stroop effect: delay in reaction time when color of words on a test and their meaning differ.

sustained attention: the ability to maintain focused awareness on a target or idea.

theta waves: pattern of brain activity during Stage 1 sleep; slower, lower-energy waves than alpha waves.

vegetative state: a state of minimal consciousness in which the eyes might be open, but the person is otherwise unresponsive.

wakefulness: aspect of consciousness that is the degree of alertness, resulting from whether a person is awake or asleep.





What is Consciousness?

CONNECTION: How much information can we hold in consciousness briefly before it is processed further, stored, or forgotten? (See Chapter 7.)

  • Activity: Have students engage in a digit span task.  Have them take out a piece of paper and read off the following series of numbers: 4432, 98325, 793627, 9963012, 10521904, and 563829610.  Ask students to indicate (via CPS or hand raising) how many they got correct.  Ask them at what point the task became more difficult.



Attention: Focusing Consciousness

CONNECTION: The mental illness schizophrenia is a marked by an inability to selectively filter out and attend to only the most relevant information from the world. For more discussion of other qualities of schizophrenia, see Chapter 16.


Training Consciousness: Meditation

CONNECTIONS: Every time you make a memory or learn something new, you change your brain by strengthening synaptic connections or growing new neurons (see Chapter 8).

  • Discussion: Have students recall how neural connections are developed and discuss automatic processing.



CONNECTIONS: There are critical periods in sensory, language, and cognitive development – meaning that if proper stimulation and experience does not occur during the peak times our brain is most sensitive to learning, our sensory, language, and cognitive abilities are forever stunted. See Chapters 3 and 5 and 9 for more on critical and sensitive periods and the brain.

CONNECTION: The functions of GABA, glutamate, and other neurotransmitters are discussed in Chapter 3.

CONNECTION: Free association is another therapeutic technique used in Freudian psychoanalysis (see Chapter 17).

  • Suggested Activity: Have students write down the most recent dream they had that they recall and then free associate.  There are no right and wrong answers here but the activity offers insight into Freud’s theory on the psyche and dreaming. 


Altering Consciousness with Drugs

CONNECTIONS: What is special about the adolescent brain? (See Chapter 5.)


MAKING CONNECTIONS: Brain Injury and Consciousness

  • People with damage to lower brain regions that control the basic bodily functions, such as sleep-wake cycles, are less likely to regain consciousness than are people who sustain damage to the cerebral cortex (Laureys, 2007).
  • Distractibility is a common problem for people with brain injury.
    • Research shows that people with brain damage, especially to the frontal lobes, have trouble blocking out extraneous information and use selective attention to stay on task (Ries & Marks, 2005).
    • Some studies show that such individuals perform poorly on the Stroop test but this may be due to the increased time it takes people with traumatic brain injury to process information overall (Mathias & Wheaton, 2007).
    • Research confirms that people with traumatic brain injury have deficits in sustained attention (Mathias & Wheaton, 2007).
    • Nature-Nurture Pointer: Brain injury can affect many different aspects of consciousness.
  • Sleeping and dreaming change with brain injury as well.
    • How people sleep while comatose or vegetative may be an important predictor of their recovery.
      • Those in a coma whose EEG patterns during sleep are organized have less disability later and a greater likelihood of survival than those whose brain patterns are less organized while sleeping (Valente et al., 2002).
    • After they have regained consciousness, sleep and wakefulness may be disrupted. Hypersomnia, insomnia, and chronic fatigue are all common.
    • Disruptions in dreaming depend on the location of brain injury. Some people who sleep normally following traumatic brain injury may still have problems with dreaming.  It seems the limbic system and its surrounding areas and the association cortex play a key role in dreaming.
    • Lastly, drug use and abuse can occur in people who are coping with the challenges of a brain injury due to resulting feelings of depression and anxiety (Anson & Ponsford, 2006).





Training Consciousness: Meditation

Nature-Nurture Pointer: Meditation training is correlated with changes in brain function and structure.

·         Suggested Website: Brain scans and meditation



Nature-Nurture Pointer:  Sleep increases neuronal growth and helps us remember things.

·         Discussion: Ask students by CPS or hand poll how many of them pull all-nighters.  Ask them how successful the method is on the test itself, the final, and long-term memory. 


MAKING CONNECTIONS: Brain Injury and Consciousness

Nature-Nurture Pointer: Brain injury can affect many different aspects of consciousness.

·         Discussion: Talk to students about the case of Terri Schiavo ( and ask them if they felt that it was right for her to be removed from life support.


Breaking New Ground: The Cognitive Neuroscience of Hypnosis

Then: The Hidden Observer Effect

·         Hilgard (1977) showed that under hypnosis, one aspect of a person’s mind can remain aware and open to stimulation from the outside, while other parts are cut off from external input. Hilgard called this phenomenon the hidden observer effect.

·         He hypnotized a man and told him he was deaf. While in the hypnotic state, the man did not respond to loud noises nearby. Next, Hilgard told the man to raise a finger if he could hear him – which he did. 

·         A second theory maintains that people behave the way they think a hypnotized person would behave. In other words, they are role-playing.

Now:  How Hypnosis Affects the Brain

·         Raz and his colleagues have studied whether hypnosis might help to eliminate the Stroop effect (Raz, Fan, & Posner, 2005).

·         The Stroop task tests visual selective attention by assessing how people deal with conflicting verbal and color information.

·         In a typical Stroop task, participants view color words (e.g., green, red, or blue) printed in different colored font.  The participants’ task is to identify the color in which the word is printed.  The delay in reaction time caused by such mismatched words is known as the Stroop effect (Stroop, 1935).

·         Raz and colleagues hypnotized 16 people – 8 who were highly hypnotizable and 8 who were less hypnotizable (Raz et al., 2005). While hypnotized, the participants received instruction on a Stroop task that they would perform a few days later in an fMRI scanner.

·         After the hypnosis session, all participants received a post-hypnotic suggestion – a suggestive statement that a particular behavior will occur sometime in the future. They were told that during the test they would see gibberish words in different colors and they would have the simple task of pushing a button corresponding to the actual color of the letters.

·         Highly hypnotizable people who received the “gibberish” suggestion identified the colors faster than the less hypnotizable people who received the same suggestion.

·         Brain scans taken during the Stroop showed that highly hypnotizable people had turned off the areas of the brain that normally process the meaning of words.

·         To study the role-playing theory, researchers compared brain scans of hypnotically induced pain, physically induced pain, and imagined pain (Derbyshire, Whalley, Stenger, & Oakley, 2004; Raij, Numminen, Närvänen, Hiltunen, & Hari, 2005).

·         All participants were highly hypnotizable.

·         Imagined pain did not activate the same brain areas as real pain but hypnotically induced pain did.

·         Participants reported actually feeling pain for both real and hypnotically induced pain, but not for imagined pain.

Next: Future Directions in Hypnosis

·         The study of hypnotically induced pain contradicts the view of hypnosis as role-playing.

·         The Stroop test study shows that hypnosis can enable some people to override automatic processes.

·         The possibility of using suggestion to deprogram automatic behaviors offers promise for the treatment of problematic behavior that has become automatic, such as substance abuse and eating disorders.

·         Smoking is another behavior that might be overcome with hypnosis. The behavior of smoking has become automatic for smokers. Perhaps the results of Raz’s work can be applied more deliberately to train smokers to see a cigarette as something they would not be interested in smoking.       





Additional Discussion Topics

  1. Ask students how long they are able to sustain full attention (you can use the CPS clickers to poll the class if you’d like).  Ask them if they think the amount of time people can sustain their attention has changed over time and why.  A good way to start is to talk about multitasking, TV, etc.  Ask them how long they think classes should be.
  2. Ask students what time they started high school and how tired they felt throughout the day.  Now ask them how they designed their college schedules (what time does their earliest class start; what time are they finished).  Their answers will reflect their circadian rhythm.  Some are morning people; others are night people.  Students are often interested in how their patterns compare to those of their classmates.
  3. Poll the class and see how many students meditate.  Ask those who do to discuss exactly what they do and what they experience in that stage.
  4. Ask students to discuss their impression of hypnosis.  Is it really an altered state of consciousness?  Is it a question of role-playing?
  5. Ask students to discuss their experiences with different sleep disorders.  Most have some experience with insomnia.  You can go to and discuss some common ways to treat them.  Many may have parents or grandparents with sleep apnea. 



  1. Have students go to and read about how to meditate.  Have them practice meditating for the week you cover this unit and write about what, if any, differences they’ve noticed as the result of the practice.
  2. Have students keep a sleep journal the week you cover this section.  Have them write down what time they go to sleep, if they wake up in the night, and what they remember dreaming about.  Have them report how many times they hit snooze each morning and how tired they felt throughout the day.  You can use this to talk about circadian rhythms, dreaming, and sleep debt.
  3. Ask students to think about the last dream they remember in detail and analyze it from a psychoanalytic, biological, and cognitive perspective.
  4. Go to and have students take the Stroop task.
  5. Give students a list of psychoactive drugs (marijuana, ecstasy, cocaine, caffeine, nicotine, alcohol, LSD, crystal meth, Valium, and morphine) and ask them to write down if they think the drug is a stimulant, depressant, or hallucinogen.  They generally think they know much more than they do.  You can link this back to Chapter 2’s discussion of intuition.


Suggested Films

  1. Sleep apnea:  
  2. Dead Again (1991) gives a good example of clinical hypnosis.
  3. Trainspotting (1996) is a movie with a good deal of information on heroin usage.  Be warned, though, there is some language and nudity.
  4. Requiem for a Dream (2000) – warning, rated R
  5. The Basketball Diaries (1995) – warning, rated R
  6. Caffeine and skin health:
  7. Quitting cigarettes and laser therapy: 
  8. NOVA Sleep:


Suggested Websites

  1. Cell phone laws:
  3. Hypnosis: Another Way to Manage Pain and Kick Bad Habits:
  4. Self-hypnosis:
  5. Dream interpretation:
  6. National Institute of Drug Use:
  7. College and Drug Use:


Suggested Readings

Agrawal, A. & Lynskey, M.T. (2008).  Are there genetic influences on addiction: Evidence from

family, adoption and twin studies.  British Journal of Addiction, 103(7), 1069-1081.

Erlacher, D. & Schredl, M. (2008).  Cardiovascular responses to dreamed physical exercise during REM lucid dreaming.  Dreaming, 18(2), 112-121.

Freud, S. (1900/1953). The interpretation of dreams. In J. Strachey (Ed. & Trans.), The Standard Edition of the Complete Works of Sigmund Freud (Vols. 4 & 5). London: Hogarth Press.

Golden, C., Golden, C. J., & Schneider, B. (2003). Cell phone use and visual attention.  Perceptual and Motor Skills, 97(2), 385-389.

Hilgard, E. (1977). Divided consciousness: Multiple Controls in Human Thought and Action. New York: Wiley.

Juliano, L.M., & Griffiths, R.R. (2004). A critical review of caffeine withdrawal: Empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology, 176, 1-29.

Lucidi, F., Devoto, A., Bertini, M., Braibanti, P., & Violani, C. (2002).  The effects of sleep debt on vigilance in young drivers: An education/research project in high schools.  Journal of Adolescence, 25(4), 405-414.

Lynn, S.J. & Rhue, J.W. (1991).  Theories of Hypnosis: Current Models and Perspectives.  New York: Guilford Press.

Most, S. B. & Astur, R. S. (2007).  Feature-based attentional set as a cause of traffic accidents.  Visual Cognition, 15(2), 125-132.

Taber, K.H. & Hurley, R.A. (2006).  Functional neuroanatomy of sleep and sleep deprivation.  Journal of Neuropsychiatry and Clinical Neurosciences, 18(1), 1-5.