Consciousness Chapter 4
Defining Consciousness Consciousness is a general state of being aware of and responsive to events in the environment and one’s own mental processes
Defining Consciousness Dualism is the notion that the mind and body are separate Materialism is the notion that mind and body are not separate
Defining Consciousness Consciousness is seen as a continuum ranging from alert attention to dreaming or drug- induced states States that differ dramatically from normal consciousness are called altered states
Defining Consciousness Metacognition is the ability to think about one’s own thinking
Theories of Consciousness Some theorists hold consciousness is related to the operation of the brain Dennet believes consciousness develops through the constant updating of experience
Evolutionary Psychology According to evolutionary psychology, consciousness has survival value
Evolutionary Psychology Pinker argues consciousness can be broken down into three issues: Sentience (feelings) Access (ability to report on the content and product of rational thought) Self-knowledge (ability to recognize one’s experiences are unique)
The Sleep-Wakefulness Cycle Humans and other animals seem to have an internal 24-hour biological clock based on what are referred to as circadian rhythms
The Sleep-Wakefulness Cycle Jet lag is one example of a disruption to the circadian rhythm that may effect performance
Sleep as Restorative Core sleep repairs the effects of waking wear and tear on cerebral functions Optional sleep fills the time from the end of core sleep until waking
Sleep Cycles Kleitman and Dement studied the sleep- wakefulness cycle using an electroencephalogram (EEG) During an 8-hour sleep period, people go through five full cycles of five stages of sleep
Sleep Stages The most dramatic finding of early research was rapid eye movement (REM) sleep REM involves high-frequency, low amplitude brain-wave activity
Figure 4.14 EEG Activity during Sleep
Sleep Stages The first four stages of each cycle are non-rapid eye movement (NREM) sleep REM occurs only after the first four stages of each cycle
Sleep Stages Stage 1 is light sleep Brain waves are of low amplitude and are fast, with mixed frequencies In stage 1, the person can be awakened easily
Sleep Stages Stage 2 involves low-amplitude, nonrhythmic brain-wave activity, and deeper sleep Stage 3 sleep involves brain waves that are slower and higher in amplitude than stage 2 Stage 3 includes some low frequency, high amplitude delta waves
Sleep Stages Stage 4 is the deepest type of sleep, and over 50% of the waves are delta waves Sleepers take about 30 to 40 minutes to go through the four stages of NREM sleep Sleepers then go from stage 4, back through stages 3, 2, and 1
Sleep Stages REM has been called paradoxical sleep because of its contradictory nature Sleep cycles develop before birth and continue to change into adulthood
Sleep Stages Newborns spend nearly half their time in REM From age 1 to age 10, the ratio of REM sleep to stage 4 sleep drops dramatically In later adulthood, people have trouble sleeping through the night, and experience a decrease in REM sleep
What Is a Dream? A dream is a state of consciousness that occurs during REM sleep usually accompanied by vivid imagery
What Is a Dream? Most people dream every night, but forget them when they do not awaken during a dream or soon after a dream Dreams are mostly visual, and most are in colour Common themes include sex, aggressive incidents, and misfortunes or worries
The Content of Dreams People sometimes report being aware they are dreaming while it is happening This type of dream is a lucid dream
The Content of Dreams Most dreams focus on events and people a person comes into contact with Environmental stimuli that do not awaken a sleeper are incorporated into dreams
Psychodynamic Views The latent content is its deeper meaning, usually involving symbolic ideas and wishes
Psychodynamic Views Carl Jung felt dreams were nature’s way of allowing access to the unconscious The collective unconscious contains primitive ideas and images inherited from one’s ancestors These inherited ideas and images are archetypes
Cognitive Views According to cognitive psychology, dreams reflect the same kind of thinking people do when they are awake Dreams express current wishes, desires, and issues the person is dealing with
Biological Views Hobson and McCarley proposed dreams (and consciousness) have a biological basis Dreams have no hidden content or meaning
Dream Theories From the psychodynamic perspective, Freud felt a dream expressed desires, wishes, and unfulfilled needs that exist in the unconscious The manifest content of a dream consists of its overt story line, characters, and setting
Sleep Deprivation The longer a person is deprived of sleep, the greater the effect will be Sleep deprivation is comparable to the effects of alcohol on driving
Why Do We Sleep? There is no satisfactory theory of why we sleep One theory is that we sleep because we are tired But fatigue does not relate directly to sleep
Why Do We Sleep? Another theory emphasizes sleep as part of circadian rhythms This theory emphasizes the brain mechanisms underlying sleep
Why Do We Sleep? Another theory says REM is important in memory formation Yet another theory says REM is important in neural maturation
Is There a Sleep Switch? What makes people go to sleep and wake up? Cells located in the front part of the hypothalamus, the ventrolateral preoptic area (VLPO) of sleeping rats seem to turn on or off, depending on the stage of sleep
Brain Structures of Sleep and Dreaming
Sleep Disorders People who fall asleep suddenly and unexpectedly have narcolepsy
Sleep apnea causes airflow to stop for at least 15 seconds Sleep Disorders
Insomnia involves problems in going to sleep Night Terrors are panic attacks occurring within an hour of falling asleep Sleep Disorders
Sleepwalking runs in families It is more common among male children It decreases with age
Sleep Disorders REM sleep disorder Lucid Dreaming