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Topic 9 - Sleep and Dreaming - Coggle Diagram
Topic 9 - Sleep and Dreaming
Sleep disorders
Insomnia
A sleep disorder where suffers have trouble falling or staying asleep
Can be acute (brief period lasting from 1 night to a few weeks) or chronic (happens at least 3 nights a week for 3 or more months)
Symptoms
Feelings of irritability, anxiety and depression
Finding it hard to fall asleep
Waking up a lot/often lying awake at night
Not feeling refreshed when waking up
Difficulty concentrating
Finding it hard to fall asleep in the day
Explanations
Lifestyle (frequent flying/shift work can affect body rhythms)
Mental/physical health conditions
Medication/food/drinking/smoking (can affect neurotransmitters/hormones)
Life stressors (e.g: work, family, health, divorce, death of a relative)
Narcolepsy
A sleep disorder where sufferers have no or impaired control over their sleep-wake cycle
Neurological disorder - caused by problems with brain functioning
Sufferers not only have daytime sleepiness, but can also fall asleep suddenly at any time without control
It is estimated about 1 in 2000-2500 people have narcolepsy
Symptoms
EDS (excessive daytime sleepiness) - feeling sleepy/falling asleep in the day, even if they had enough sleep last night
Cataplexy - episodes of loss of muscle power/tone caused by strong emotions
Hallucinations/vivid dreams
Sleep paralysis
Fragmented sleep - waking up several times a night and taking a while to fall back asleep
Explanations
Lack of hypocretin (a chemical in the brain that regulates the SWC)
Some sufferers have damaged or missing cells in the hypothalamus that produce this chemical
Genetics (10% of people with narcolepsy have family members who also have it
Stress/Trauma
Evolution
Cataplexy can be considered a survival characteristic (staying still to survive)
Studies
Freud - Little Hans (1909)
Method: Case study
Longitudinal - lasted 3 years, ending when Hans was 6
Aim: Help LH overcome his phobia of horses and find proof for his theories on how phobias develop, the Oedipus complex and the effectiveness of psychoanalysis as therapy
Hans had two dreams you need to know:
Dreamed his mother was gone - woke up crying
Freud claimed this dreamed showed Hans was not only anxious his mother would leave him, but was afraid his father would take her - unconscious wish to sexually possess his mother revealed itself in dream
Dreamed about a big giraffe and a crumpled one - Hans took the crumpled one and the big one shouted at him
Crumpled one was his mother, big one was his father
LH like getting in bed with parents in morning - father didn't like him doing it
Shouting was symbol of LH wanting to take mother from father - evidence young boys have sexual feelings for their mother, but feel guilty about it and fear their fathers
Evaluation
Strengths: Conducted over a long period of time (lots of information and detail gathered), ethical (cured Hans' phobia),
Weaknesses: Freud only met Hans twice (most information received from father), dream interpretation subjective, hard to generalise study, there are other explanations for Hans' phobia (he saw a horse die)
Procedure
Freud gained data from written letters and reports from Hans's father, as well as meeting him a few times
It foucsed on Hans's dreams and fear of horses/leaving home
Imagination and role play helped Hans get over his unconscious fear of his father, and horses in turn
Hans especially feared horses with black straps around their eyes and mouth
Freud believed this specific fear was a symbol of Hans's fear of his father, who had a moustache and wore glasses
Conclusion
Freud used this case study as evidence of the psychosexual stages of child development
Hans's fear of his father, represented by his horse phobia, was evidence of the Oedipus complex
Siffre (1972)
Method: Field experiment
Only one participant (Siffre himself)
Aims: Investigate space travel's effects on a person's body clock/the natural sleep-wake cycle without external environmental cues/is it 24 or 48 hours?
Procedure
Siffre went into Midnight Cave in Texas and stayed there for 6 months without seeing daylight, other people or anything to indicate time
His only communication with the outside world was two phone calls to researchers a day - one to say when he woke up and thought it was daytime, and another to say when he went to bed. This would turn lights in his tent on and off respectively.
He recorded his thoughts and experiences in a diary and conducted tests on himself, including:
Memory tests
Recording blood pressure
Physical dexterity (using a cycle machine, threading beads on a string)
Shaved daily and weighed his beard trimmings to test his hormonal cycle
Mental acuity tasks
Results
Siffre became depressed, had suicidal thoughts and even wanted to trap a mouse for companionship
His eyesight and STM worsened in the cave
His SWC started at just over 24 hours, but by the end of the study, it could vary between 18 and 52 hours
Conclusion
Long periods of isolation like Siffre's in a confined space are not suitable for space travel
Without cues for daylight and time, the SWC varies hugely
External cues are needed for humans to work out time
Evaluation
Strengths: Key variables controlled, ecologically valid (field experiment), lots of quantitative and qualitative data gathered.
Weaknesses: Siffre had artificial lights (can reset body clock), only one participant, he wasn't isolated from all external influences on sleep
Theories
Freud
Believes dreams are a way for unconscious wishes and desires to enter the conscious mind and be fulfilled
Through talking with a therapist, the meaning of dreams can be uncovered
Dreams have two types of content:
Manifest: What actually occurs in the dream (story)
Latent: Underlying psychological meaning of dream, unconscious wish/desire being fulfilled. The process of changing this into the manifest content is called dreamwork
Evaluation
Strengths: Uses qualitative information from real individuals, involving patients increases validity (they must accept a meaning), supported by evidence such as Little Hans
Weaknesses: Interpretation of dreams is heavily subjective, his ideas cannot be specifically tested quantitatively or scientifically, case studies are hard to generalise
Hobson and McCarley's activation synthesis theory
Neurobiological explanation for dreaming
Believes dreams have no meaning, but are created by the brain attempting to make sense of activity that occurs during REM sleep
Muscles are paralysed to inhibit movement and sensory information is not being picked up (blockade), so the activity must come from somewhere else
Hobson and McCarley believe this activity is caused by random neurons activating, sending messages and creating thoughts in the brain
Evaluation
Weaknesses: Cannot explain phenomena such as lucid dreaming or children dreaming less, they used cats to support their theory, some people say their dreams do make sense, Hobson himself would later discredit this theory
Strengths: Supported by research done by them, more credible than Freud's because it can be tested scientifically, is still being developed and refined
Influences on sleep
Internal
Hormones
Melatonin makes you feel sleepy
Cortisol helps to wake you up
These hormones are controlled by the pineal gland
The suprachiasmatic nucleus (SCN) are a group of cells that control our circadian rhythms
It uses external cues such as sunlight to help it do so
A lower body temperature makes it easier to sleep
Sudden brain activity can wake someone up
External
Light detected by the eyes tells the pineal gland to stop secreting melatonin and start secreting cortisol
Food can make it harder to fall asleep (digestion)
It is easier to sleep in cold outside temperatures
Evaluation
Weaknesses: Reductionist (focuses on biology and ignores the choice to sleep), research on it (e.g: Siffre's) lacks validity
Strengths: Applicable to medicine/drug therapy, Friedman and Fisher have found a 90 minute clock exists in the body, has heavily contributed to our understanding of the brain and behaviour, Bovin et al showed that external factors influence circadian rhythms
Features of sleep
Stages
NREM (Non Rapid Eye Movement) Stage 1 - Sleeper is easy to wake, muscle/brain activity begin reducing
Stage 2: Body temperature begins dropping, heart rate/brainwaves slow
Stage 3: Deeper sleep, harder to wake, brainwaves mostly slow delta
Stage 4: Deepest sleep, eyes/muscles don't move, sleepwalking can happen here
REM (Rapid Eye Movement) sleep: Eyelids flicker quickly, dreaming and waking usually occur here
Cycles
Sleep-wake cycle: A circadian rhythm consisting of about 16 hours where a person is awake, followed by about 8 hours where they are asleep.
Sleep cycle: An ultradian rhythm of about 90 minutes where a person goes through all 4 stages of NREM sleep, followed by a period of REM sleep.
The fraction of the cycle in which REM occurs increases each time the cycle repeats in a night.
Stage 1 of NREM sleep only occurs during the first cycle of a night. Later cycles start at stage 2 and finish with REM.