Sleep and Dreaming Flashcards
How many stages of sleep are there and how long for?
5 stages
each cycle of sleep is 90 mins
What happens in stage 1 of sleep?
light sleep can be easily woken muscles are less active eye movements slow twitch suddenly go through alpha and theta brainwaves
What happens in stage 2 of sleep
brainwaves are slower eye movement stops bursts of brain activity body temperature drops heart rate slows
What happens in stage 3 of sleep
deep sleep
slow delta waves
also some fast waves
this stage is in between light and deep
What happens in stage 4 of sleep?
deep sleep all waves are slow delta waves hard to wake you no eye movement can feel disorientated can experience night terrors or sleepwalking
What happens in REM sleep/what is it?
20% of sleep is REM for infants 50% is REM REM = rapid eye movement eyelids flicker quickly dreaming occurs sensory blockade neurons are shot off = movement inhibition rapid, shallow and irregular breathing eyes jerking muscles paralysed heart rate blood pressure rises stimulates increase of proteins some people report dreaming in NREM sleep, not always accurate
How long people need sleep for
adults = 7 or 8 hrs
teenagers = 9 hrs
age 65< = sleep stops, very sleep deprived so can’t perform functions well
What are circadian rhythms
human bodily rhythms
sleep-wake cycle
What are ultradian rhythms
rhythms that occur in <24 hrs
just sleep
Factors affecting the sleep-wake cycle
Jet lag = sleep-wake is triggered by light and time cues, different can cause irritability and poor concentration and tiredness
Shift work = different time cues affect biological rhythms
Internal influences on sleep
Hormones = sleep resets hormones
= can affect sleep because of stress, under stress ACTH releases cortisol, causing alertness -> hard to fall asleep
= people with insomnia produce too much cortisol/at wrong time
= melatonin signals need for sleep
= triggered by darkness
= synchronises circadian rhythms
=affects time of sleep
External influences on sleep
exogenous, environmental features: light, time cues, stress, eat and drink, medication
zeitgebers:
- regulate body’s circadian rhythm
- 12 month cycle
- mood and performance
- jet lag, shift work, light
- light lets internal body clock know whether its day or night = when to sleep
- body clock reset over 24 hr period
- entrainment =bodily rhythms matches to their environmental triggers -> light you are awake
Strengths and weaknesses of internal influences
+ hamster study = removed SCN from hamsters and sleep-wake patterns became random
+ human study of blind man = found his bodily rhythms are closer to 24hrs, circadian rhythms are governed by internal influences
+ Li-You Chen et al (2015) = melatonin controls sleep found in rats, sleep deprivation reduces melatonin levels -> melatonin reduces sleep
- animal studies cannot be generalised
- individual differences to being blind, hard to generalise to people who aren’t blind and without that specific blindness
Strengths and weaknesses of external influences
+ practical applications for understanding body clocks in humans = zeitgebers
+ Ralph and Skene agree that light synchronises bodily rhythms
- Siffre found the sleep-wake cycle could be 48 hours, studies differ
- situation of sleep-deprivation studies are not natural, lack validity
Name some sleep disorders of depression
Insomnia
Narcolepsy
Symptoms of insomnia
difficulty falling asleep
waking up a lot during the night
frequently lying awake during night
not feeling refreshed on waking
finding it hard to sleep in day when tired
feelings irritable and unable to conentrate
How can insomnia be caused?
Lifestyles = jet lag or working shifts
Health conditions = mental-> depression physical -> heart problems
Medication, food and drink = neurotransmitters and hormones, caffeine and diet pills, smoking cigarettes, alcohol keeps people in the light, antidepressants can stop REM sleep
What is narcolepsy?
person has no control over their sleep-wake cycle
fall asleep suddenly
1/2000 people
Symptoms of narcolepsy
EDS (excessive daytime sleepiness) = feel extreme sleepiness, fall into an uncontrollable daytime sleep anytime
Hallucinations
Cataplexy = loss of muscle power, 70% of people with narcolepsy
Sleep paralysis = abnormal REM sleep
Explaining narcolepsy
Brain chemicals = hypocretin -> keeps us awake
=cells in hypothalamus produce hypocretin that damaged or missing, so cannot control when awake
Genes = 10% of people with narcolepsy have other family members with disorder
Stress or trauma = Barker made link between then
Evolution = might be advantageous for animal to stay still to stay alive -> survival characteristic
Explaining narcolepsy
Brain chemicals = hypocretin -> keeps us awake
=cells in hypothalamus produce hypocretin that damaged or missing, so cannot control when awake
Genes = 10% of people with narcolepsy have other family members with disorder
Stress or trauma = Barker made link between then
Evolution = might be advantageous for animal to stay still to stay alive -> survival characteristic
What is the id, superego and ego
id = "I want" superego = "you cannot have" ego = balance inbetween
What is manifest and latent content?
Manifest content = story of the dream
Latent content = meaning of dream, uncovers unconscious thinking
Dreamwork
The way the mind keeps unconscious thoughts hidden to protect mind = disguises by repressing thoughts and ideas
Condensation = many ideas appear as one idea in a dream
Displacement = something unimportant seems to be important, shifts attention away from important thing
Secondary elaboration = ideas from dreamwork to build a whole story
Strengths and weaknesses of Freud’s theory of dreaming
+qualitative, detailed and focused on real individuals
+had validity
+he saw power of the unconscious which cannot be easily studied
+Guenole et al found that more people reported more dreaming if they heard noise, noise did not wake them because dreaming kept them asleep = sensory blockade
-cannot be easily tested
-the unconscious or dreamwork cannot be measured objectively = unscientific
-each analysis was unique to individual
Hobson and McCarley vs Freud’s theory
Freud = dreams have meanings
Hobson and McCarley = dreams are random
Activation synthesis
Hobson and McCarley = random thoughts are what we dream
Neurons randomly firing send thoughts makes brain generate “nonsense”
Strengths and weaknesses of activation synthesis
+people observed in sleep lab
+study is still being used
+other studies supported, cat used to see which areas of brain light up
-unethical to use animals
-animal studies cannot be generalised to human functioning
-1977 theory (too long ago)
Freud’s aim
look at how children develop
how Oedipus complex and psychosexual develops
Procedure of Freud’s
gathered lots of detailed information directly from boys parents and some from Hans
looked at Hans’s phobia of horses
Hans was afraid to go out of house
Freud analysed what little Hans’s reported to find out Hans’s unconscious that was causing the phobia
Hans’s phobia of horses
he see a horse fall down and die in the street
he is mainly scared of horses with black bits around mouth
black bits = Hans’s father’s moustache
Hans feared his father because his father would be angry with Hans for wanting his mother - Oedipus complex
An early dream
had a dream that he thought his mother was gone and he had no mummy
anxiety his mother would leave - Oedipus complex
fear his father would take mother away
The giraffe dream
had dream that there was a big giraffe in the room and a crumpled one
big giraffe = penis
Hans denied this so,
big giraffe = Hans’s father and crumpled = mother
Little Hans wanted to take his mother away from father
Strengths and Weaknesses if Freud’s study
+Freud gathered a lot of in-depth and detailed information
+Little Hans was very carefully documented
+clear what information was given to him and what was Freud’s interpretation
-Freud’s parents knew about Freud’s theory so could have only passed on information that suited complex
-bias
-not generalisable = one person
-learning explanation = Hans saw horse die
Siffre aim
wanted to see how astronauts would be affected in space
not having zeitgebers to set biological clock
wanted to see his “natural” sleep-wake cycle when deprived of external cues
Siffre’s procedure
Texas
went >6 months without seeing daylight
has tent on wooden platform with bed, table and a chair
ate frozen food and drank water
undertook experiments while in cave
removed all zeitgebers
when Siffre woke up, he phoned team of researchers
did memory and physical tasks e.g. target practice
did exercise - riding bike
kept diary of his thoughts
when he felt tired he slept and researchers turned off lights
Siffre’s results
became depressed and upset at lack of freedom
wanted to trap mouse - loneliness
thought about suicide
effects of dark and loneliness were severe
worse eyesight and psychological problems
short-term memory was affected
sleep-wake cycler was >24 hrs
varied from 18-52 hrs
Siffre’s conclusions
lot of variation in sleep-wake cycle when cues to daylight and time were missing
astronauts would need companionship
Strengths and weaknesses of Siffre
+qualitative and quantitative data
+done over long period of time
-lights came on when Siffre woke up and went off when asleep, could have affected internal body clock
-not being generalisable, one case study
-has external zeitgebers = noise of mice, damp, telephone connections to research team and other issues
