“normal” state - being awake Other states - daydreaming,

dreaming, hallucinations, starvation, sensory deprivation, hypnosis, meditation

Unconsciousness = parallel processing system (not Freud’s unopened box of childhood memories)

Biological Rhythms

Circadian rhythm - daily biological clock

Suprachiasmatic nucleus (SCN) in the hypothalamus senses light and controls clock

Circadian rhythm controls body temperature - rises in early morning, peaks during the day, dips in early afternoon, and drops at night

Circadian rhythms are affected by time changes, traveling across time zones, bright lights before bed

Because of electricity, most people today do not get enough sleep Cell phones/tablets also create light that

fools the SCN

Sleep

Sleep Cycles: Stages of Sleep The awake brain produces alpha

waves You don’t remember the moment

that you fall asleep Stages 1-4 are NREM sleep (non-

REM)

Figure 5.4 Brain waves and sleep stages  The regular alpha waves of an awake, relaxed state are quite different from the slower, larger delta waves of deep Stage 4 sleep. Although the rapid REM sleep waves resemble the near-waking Stage 1 sleep waves, the body is more aroused during REM sleep than during Stage 1 sleep.

From Dement, 1978

© 2010 by Worth Publishers

Stage 1

Stage 1 sleep often includes hallucinations (dreams with no plot), includes the hypnagogic sensations of

falling or weightlessness Stage 1 is short (less than 20

minutes)

Stage 2

Brain waves have “sleep spindles” - bursts of rapid, rhythmic activity

Sleeptalking may happen here Lasts about 20 minutes

Stage 3

Transitional, short Delta brain waves begin (large and

slow)

Stage 4

More delta waves Deep sleep - harder to wake

someone up from Sleepwalking and bedwetting

typically happen here, mostly in children

REM sleep

After 4, you go back through stages 3 and 2 to Rapid Eye Movement sleep

Brain waves are similar to stage 1, but breathing and heart rate increase and eyes move

Motor cortex is active but brainstem blocks its signals (leaving you basically paralyzed)

REM sleep cont.

Dreams happen in REM sleep Unlike stage 1, these are typically

emotional, detailed, and have a continuous plot

REM is “paradoxical sleep” - brain waves look active but body is very relaxed

Sleep Cycle

Sleep cycles last about 90 minutes After the first cycle, stage 1 is

replaced with REM As the night goes on, you have less

of stages 3 and 4 and more REM

Figure 5.6 The stages in a typical night’s sleep Most people pass through the five-stage sleep cycle (graph a) several times, with the periods of Stage 4 sleep and then Stage 3 sleep diminishing and REM sleep periods increasing in duration. Graph b plots this increasing REM sleep and decreasing deep sleep based on data from 30 young adults.

From Cartwright, 1978; Webb, 1992

© 2010 by Worth Publishers

Do We Need Sleep?

People can stay awake for about 8 to 10 days, but higher-level functions such as concentration and perception are significantly affected

Rats and people who go more than two weeks without sleep die

Effects of Sleep Loss

Diminished productivity and concentration

Irritability Increased production of stress

hormone cortisol, which stimulates production of body fat

Increased production of hunger hormone ghrelin (and decrease of leptin, which suppresses hunger)

Suppresses immune system’s capacity to fight of viral infections and cancer

Slower reaction time More errors on visual and memory

tasks Changes to metabolic and endocrine

systems that mimic aging

How much sleep do we need? Infants and young children need

more than adults Most adults will sleep 7.5-9 hours per

night when they have no restrictions Our brains track “sleep debt” for at

least two weeks

Theories on Sleep

Sleep protects us - keeps us from running around in the dark

Sleep helps us recuperate - repair brain tissue from free radicals

Sleep helps memory - memories of the day’s new info are built and stored during sleep

Sleep boosts creativity - people are more insightful at problem solving with more sleep

Sleep helps physical growth - pituitary gland releases growth hormone during sleep

Sleep Disorders

Insomnia - consistent inability to sleep Sleeping pills and alcohol can make it

worse Natural solutions:

Exercise Avoid caffeine Relax in dim light Sleep on a consistent schedule and don’t

spend more than 7 hours in bed

Narcolepsy - uncontrollable “sleep attacks” where patients drop in to REM

Attacks usually last less than 5 minutes but may happen at any time

Genetic cause identified (affects 1 in 2000 people)

Sleep apnea - temporarily stop breathing during sleep

Lack of oxygen wakes patients up throughout the night, preventing them from reaching delta-wave sleep

Symptoms: terrible snoring, wake up feeling tired

Linked to obesity, cured with a mask that forces air through nose

Night terrors - not the same as nightmares

Typically happen to children in stage 4 sleep, often not remembered by child

Child may scream, breath quickly, sit up, and/or speak, without waking up

Sleepwalking - runs in families, mostly affects children

Typically not dangerous, many people return to bed on their own

Happens during stage 4 sleep

Dreams

Content of Dreams

Manifest content (Freud’s idea) - what actually happens in a dream

More commonly negative than positive

Trauma commonly causes nightmares

Dream content varies with culture Often includes details from the day

or things we’re worried about

Theories on Dreams

Freud: to satisfy our wishes in a safe, socially acceptable way

Believed dreams are symbolic versions of latent content (unconscious motives and sexual desires) that could be analyzed to learn about someone’s unconscious

No longer considered scientific

Dreams may help us file away memories by processing new information

Dreams may develop and stimulate neural pathways (infants spend more time in REM sleep than anyone else)

Dreams may make sense of neural static - random neural firing may be interpreted as dreams (activation synthesis theory) Dreams activate visual processing areas

and the emotional limbic system Dreams reflect cognitive

development Use language and other skills as children

learn them

REM sleep is biologically necessary Animals/people deprived of REM

sleep will have “REM rebound” when they are allowed to sleep unrestricted

REM occurs in mammals and may reflect the ability to learn

More than one theory of dreaming may be true

Addiction

Addiction can be physical (withdrawal causes pain or cravings) or psychological (usually for stress-relieving drugs)

Addiction take time to develop and some people never develop one

While therapy to overcome addiction is usually helpful, it is not necessary for everyone

Addiction was traditionally used to talk only about substance abuse (drugs/alcohol)

Can you be addicted to things like food, the Internet, video games, gambling, etc? Or does this just give people an excuse?

Influences on Drug Use

Biological: Having an identical twin puts the other

twin at higher risk for alcohol dependence and marijuana use than a fraternal twin

Mice can be bred to prefer alcohol to water

Researchers are investigating genes that contribute to addiction

Psychological influences: Feeling that one’s life is meaningless Depression, low self-esteem, abuse, or

loneliness Social-cultural influences:

People do it at parties (to be social) Actions of friend group Some religions discourage drug/alcohol

use Cities have higher rates than rural areas