topic 9 - sleep and dreaming

the four stages of sleep

the four stages of sleep

stage 1 - light sleep where muscles are less active and eye movements are slow

stage 2 - brainwaves are slower, eye movements stop, heart rate slows and body temperature starts to drop

stage 3 - between light and deep sleeps with slow delta brainwaves

stage 4 - deep sleep with slow delta brainwaves and no eye movements

REM sleep

when there is rapid eye movement and eye jerking

dreaming occurs during this time

there is a sensory blockade

signals shut off neurons in the spinal cord which causes movement inhibition and paralysis

rapid, shallow and irregular breathing

the sleep cycle

in one night’s sleep, you go through five cycles of the stages of sleep and REM sleep

each cycle lasts about 90 minutes

as the cycles progress, REM sleep lasts longer and there is less deep sleep

benefits of sleep

thought to help neurones repair themselves

helps to avoid the breakdown of proteins

REM sleep stimulates learning and is associated with an increase in proteins

dreaming takes place in REM sleep

types of bodily rhythms

circadian rhythms

ultradian rhythms

circadian rhythms

human body rhythms that have a daily (24-hour) cycle

the superchiasmatic nuclei (SCN) control the circadian rhythms

ultradian rhythms

rhythms that occur in a period of less than 24 hours

internal influences on sleep

hormones

melatonin

a hormone that signals the need for sleep

triggered by darkness

synchronises the circadian rhythms

produced in the pineal gland

external influences on sleep

zeitgebers

zeitgebers

environmental or external cues that regulate the body’s circadian rhythms

main zeitgeber is light

light sensitive cells in the retina of the eye let the internal body clock know whether it is day or night

strengths of the internal influences on sleep explanation

there is evidence from animals that the suprachiasmatic nuclei (SCN) have the role of setting the biological clock

Miles et al. (1977) suggested we have circadian rhythms governed by internal factors

Li-You Chen et al. (2015) confirm that the pineal hormone melatonin is important for controlling sleep

weaknesses of the internal influences on sleep explanation

evidence from animals studies makes it a problem in generalising the results to humans

evidence relating to human blindness is weak

strengths of the external influences on sleep explanation

there are practical applications for understanding how our biological clocks work

Ralph Mistlberger and Debra Skene (2004) agree that light is the main way bodily rhythms are synchronised

weaknesses of the external influences on sleep explanation

difference in findings

studies are conducted in a artificial setting, so lack of validity

insomnia

refers to problems with sleeping

can be caused by lifestyle, health conditions and what is taken into the body

symptoms of insomnia

difficulty with falling asleep

waking up a lot during the night

frequently lying awake during the night

not feeling refreshed on waking

finding it hard to fall asleep in the day when tired

feeling irritable and unable to concentrate

narcolepsy

where a person has no control over their sleep–wake cycle

can fall asleep suddenly at any time without being able to control such attacks

caused by lack of hypocretin, genetic influences, stress and evolution

hypocretin

a chemical in the brain that keeps us awake and regulates the sleep–wake cycle

stress and trauma

Wayne Barker (1948) looked at situational stress and narcolepsy and made a link between them

symptoms of narcolepsy

hallucinations and vivid dreams

cataplexy (loss of muscle power)

sleep paralysis and abnormal REM sleep

Freud’s (1900) theory of dreaming

the unconscious mind accounts for about 90% of our thinking and holds all thoughts and wishes not in the conscious or preconscious

dreaming can uncover unconscious wishes

manifest content

the story the dreamer tells of what happens in a dream

latent content

the deeper meaning behind what it is said the dream is about

dreamwork

the transformation of unconscious thoughts into dream content

strengths of Freud’s (1900) theory of dreaming

data was qualitative, detailed and focused on real individuals, so there was validity in the findings

this was a unique approach

there is some evidence to support the theory like Guénolé et al. (2013)

weaknesses of Freud’s (1900) theory of dreaming

dreaming cannot easily be tested

cannot be measured objectively and so his theory is unscientific

case studies meant each analysis was unique to the individual so it was not generalisable

Hobson and McCarley’s (1977) activation-synthesis theory of dreaming

the brain is active during REM sleep where our muscles are not working and so there is movement inhibition and sensory blockade

random thoughts are sent to brain from neurones being randomly activated

random thoughts are what we dream and these dreams seem to make sense

strengths of Hobson and McCarley’s (1977) activation-synthesis theory of dreaming

there is evidence to support the theory

using animals for studies means there are no ethical issues

weaknesses of Hobson and McCarley’s (1977) activation-synthesis theory of dreaming

using animals for studies makes the results less generalisable

people can associate random thoughts with events during the day

theory was built on and amended

aim of Freud (1909) Little Hans

build evidence for his theory of how children develop

procedure of Freud (1909) Little Hans

gathered a lot of detailed information from the regular reports sent to him by the boy’s parents and directly from the boy

looked at Hans’s phobia of horses and his dreams

idea was to reveal to Hans his own unconscious wishes and desires so the phobia could be cured

used traditional psychoanalysis, where he listened to what was said and dreamed, considered how these issues are symbols of hidden unconscious desires and then interpreted the symbols to uncover the desires

results of Freud (1909) Little Hans

Hans particularly did not like horses with black bits around the mouth which was thought to be a symbol for Han’s father

fear of horses showed Hans’s unconscious fear of his father because his father would be angry with Hans for wanting his mother (Oedipus complex)

to help with his phobia, he imagined his father in a different role, that of ‘grandfather’

Hans once had a dream that his mother was gone and Freud said this was a dream showing anxiety that his mother would leave

Hans had another dream about a big giraffe shouting at him for taking away a crumpled giraffe and this was linked to Little Hans wanting to take his mother away from his father

conclusions of Freud (1909) Little Hans

children develop in a series of psychosexual stages

theory about the Oedipus complex in small boys was supported by the Little Hans study

the horse represented Hans’s father and the fear showed the Oedipus complex in action

strengths of Freud (1909) Little Hans

gathered a lot of in-depth and detailed information about the boy so great validity

scientific because it was very carefully documented and objective

weaknesses of Freud (1909) Little Hans

case study was uniquely about Hans so not generalisable

most information came from Han’s father, leading to bias

there is a learning explanation to explain Hans’s phobia other than Freud’s theory

aims of Siffre (1975)

to see how people would get on when travelling through space, where they could be isolated and would not have zeitgebers

to see what his ‘natural’ sleep–wake cycle was when deprived of external environmental cues

procedure of Siffre (1975)

went into Midnight Cave, Texas, USA, on 14 February 1972 and came out in September of the same year

spent 6 months without daylight

lived in a large chamber that was about 130 metres from the entrance of the cave, down a 30 metre vertical shaft

had frozen food and water

every time Siffre woke up and thought is was 'day', he phoned his team of researchers above ground to say he was awake and they put lights on before he began his daily experiments

recorded his thoughts in a journal and did muscle exercises, like target practice

when he was ready for sleep, the team of researchers above ground turned the lights off

results of Siffre (1975)

became depressed and upset at his lack of freedom

became desperate for companionship

began to think about suicide

came out of the cave with worse eyesight and psychological problems

his short-term memory was affected

did not get the ‘days and nights’ right

periods of sleep–wake were longer than 24 hours

conclusions of Siffre (1975)

the body clock might be manageable

period of isolation in a confined space was not manageable

astronauts would need companionship

time is not something humans work with and understand without external cues

strengths of Siffre (1975)

rich qualitative and quantitative date was produced because of careful documentation, making the result have great validity

having being done over a long period of time also gave it great validity

weaknesses of Siffre (1975)

strong artificial lights were used and would affect his internal body clock, acting as cues as found by Czeisler et al. (1999)

one-person case study made the results less generalisable