REM sleep resets the brain, memories consolidated, protects established memories, decision making, creative connections are made, toxins are removed.
How does sleep help physical repair?
Slow wave sleep helps heal cells, especially those in the cardiovascular system.
Helps maintain hormone balance and increase immune activity.
How does sleep help emotional stability?
Reduces cortisol levels, a hormone related to stress.
Stage 1 - sleep onset
Light sleep
Muscles less active, eye movements slow, can twitch suddenly
Can be easily awoken
Alpha and theta brain waves
Stage 2 - late night stage
Eye movement stops
Theta waves slow with occasional bursts of rapid brain waves
Lose conscious awareness of outside world
Stage 3 - light sleep / deep sleep bounaries
Extremely slow brain waves
Delta waves alternate with shorter, faster waves
Stage 4 - only delta waves present
No body movement or muscle activity
More growth hormone released, which helps with physical repair
REM sleep
Breathing quicker and less regular
Muscles temporarily paralysed
Brain waves similar to when awake
Normally 3-5 intervals of REM sleep per night
Most dreams occur
Starts short with long periods of deep sleep, later in the night REM sleep increases in length
Circadian rhythm
The sleep-wake cycle every day
Exogenous zeitgeber
Any signal that the brain uses for the purpose of clock resetting, eglight, food, exercise, social interactions
Endogenous pacemaker
Internal biological clocks that manage bodily rhythms
Pineal gland
Communicates information about environmental lighting to the rest of the body. Controls circadian rhythms; secretes melatonin: the release peaks at midnight and we sleep better when it is released; exposure to light during the night reduces melatonin production and release.
SCN
A part of the brain that regulates circadian rhythms. It delays the release of melatonin until dark.
The role of the hypothalamus
When we are exposed to light, it stimulates a neural pathway from the retina to the hypothalamus. This is where the SCN is located, which sends signals to other parts of the brain that control hormones, body temperature, and other processes that play a part in whether we feel sleepy or awake.
Sleep onset insomnia
Taking a long time to get to sleep but can sleep through the night.
Sleep maintenance insomnia
Wakes frequently during the night.
Primary insomnia
Not related to any other problems but are problems in themselves. No known cause, so most likely to be caused by bad sleeping habits such as staying up late.
Secondary insomnia
Stem from another problem which can be physical or psychological e.g. stress or depression or too much caffeine.
Freud's theory of dreaming - the unconscious mind
The part of the mind that people are not aware of but holds thoughts and memories.
Repression
The process of pushing unpleasant thoughts and experiences into the unconscious mind.
Wish fulfilment
Satisfying urges and desires.
Manifest content
The actual content of your dreams.
Latent content
The underlying meaning of the dream hidden in the latent content.
Ego
Obeys the reality principle (we can't have everything we want)
Super ego
The internalised voice of parent's and society's morals. The source of guilt and shame.
Id
Obeys the pleasure principle (every wish must be satisfied). Mostly in the unconscious mind.
How do we access the unconscious mind?
Freud believed the only way was to bring the unconscious into the conscious through dreams.
Dreams - wish fulfilment
When you dream, your ego's defences are lowered, so repressed wishes can reach your conscious awareness. Repressed wishes and memories are distorted in our dreams. The more unpleasant the wish or memory, the more distorted it becomes.
Criticism of Freud's theory - The theory is too subjective
Dream interpretation is very open to opinion as a number of people can hear the same description of a dream and have differentinterpretations of it.
Criticism of Freud's theory - It is difficult to test
Its concepts are not objective enough and dreams cannot be easily verified. A big part of the theory relies on the unconscious mind, but this can't be asked about/observed.
Criticism of Freud's theory - Cultural and historical bias
Freud's themes, especially how dreams were interpreted, my have been influenced by the culture at the time. E.g. in Freud's time society was very strict about sex, so the idea of repressing lust and desire made sense. However today people have more liberal attitudes to sex, but this doesn't mean that the manifest content of dreams are very different.
Wolfman - sample
Freud used the pseudonym 'Wolfman' to protect the patient's identity. Later revealed to be Sergei Pankejeff: a man in his 20s from a wealthy Russian family. In 1906 his sister killed herself and in 1907 his father killed himself, leading to Pankejeff's own depression.
Wolfman - design
Longitudinal case study. Carried out a series of interviews between 1910 and 1914, which he analysed 15 years later.
Wolfman - conclusions
The unconscious mind can have a significant effect on behaviour. It illustrates the process of repression, where traumatic events are pushed into the unconscious mind as a safety mechanism. However, it also shows that repressed memories can find their way back into the conscious mind through dreams that people have and then recall.
Wolfman criticisms - Sample size too small
It is not reliable to bass a theory of dreams, which is supposed to apply to all, on the case of one person. It might be that other people don't use dreams as a way of symbolising traumatic experiences.
Wolfman criticisms - The Wolfman may only represent people with mental health problems.
Even if we accept that we can make some generalisations based on the Wolfman's experiences, they may not apply to people with good psychological health. Everybody dreams, but not everybody has traumatic life histories or mental health issues.
Activation synthesis theory
Dreams are a result of our brains trying to make sense of brain activity during sleep.
What does the theory day happens in our brains, which causes dreams?
Neuronal activity increases in the pons and random brain waves are generated. These waves travel up to the cerebral cortex in areas that would normally interpret sensory information, e.g. occipital lobe, limbic system. The information is treated as real sensory information. Through interpreting the stimulation, synthesis occurs; using stored memories to make sense of the information.
Criticisms of the activation synthesis theory - Too reductionist
Dreams are complex and packed full of meaning. you cannot reduce this down to simple neuronal processes.
Criticisms of the activation synthesis theory - Dreams often follow patterns
Dreams can be recurring or quite coherent. This does not fit with the idea that they are generated by random brain activity.