Sleep And Dreams : cognitive Approach

Question 1

What is the cognitive approach to sleep

Answer 1

The cognitive approach states that the purpose to sleep is to facilitate our cognition (thinking) for example by organising memories

Question 2

Sleep and information processing + evidence

Answer 2

• one key idea is that sleep facilitates information processing. According to this view , switching off for a nights sleep allows new information to be sorted stored and consolidated.
• Mazza et al (2016) found that by splitting study sessions over two days with a nights sleep in between reduced the practice time needed in half.

Question 3

Key theory - cognitive theory of dreaming

Answer 3

The reorganisation theory (Crick and Mitchson 1986)

Question 4

What does the reorganisation theory of dreams propose? (Crick and Mitchison 1986)

Answer 4

• based on reverse learning meaning that learning can be undone in REM asleep - or that we dream to forget / get rid of useless memories during REM asleep.

Question 5

The two categories of memories proposed by crick and mitchison (information collected through the day stored in our memories)

Answer 5

Crick and Mitchison proposed we have two types of information Coll fed through the day sttored in our memories

1) adaptive memories : these are memories useful to us and we need to use. for example where you saw your sister hide her huge bar of toblerone
2) parasitic memories : useless pieces of information we pick up during the day fir example the colour of shoes your mother in law was wearing

Question 6

How does the reorganisation theory work

Answer 6

• during REM when we are dreaming , our brains are not being used to process the information we need when awake , so our brains use this time to throw out parasitic memories (unwanted memories from the day)
• they believed that the cortex can become overloaded so parasitic memories are deleted during sleep to make space . Random memories are activated and dreams are produced.
• dreams are a mechanism for unlearning superfluous associations. Dreams with a pathological or harmful nature such as obsessions or delusions expel unwanted thoughts - which If not got rid of could lead to obsessive or paranoid behaviour.

Question 7

Evidence of reorganisation theory - network computer models

Answer 7

Crick and Mitchison ran neural network computer models of learning , finding that the storage of such systems is easily overloaded and that reverse learning could address this problem. The models acted in random and repetitive ways - which the researchers compared to human obsessions and hallucinations

Question 8

Evidence of reorganisation theory - czeislar et al 1990

• aim
• findings and how they relate to the cognitive approach

Answer 8

Aim - whether exposure to very bright light (zeitgeber) in the workplace at night and then total darkness for the daytime sleep can reset the circadian rhythm to help night shift workers cope bette with changing shift patterns
Findings which relate to cognitive approach : due to a lack of sleep
: - men in the experimental group slept 2 hours more each day than men in the control group. - Cognitive skills in the experimental group were higher than the control group from midnight to 8am (when night shift workers are working and normal people are sleeping)
- mean values for alertness were higher in the experimental group than the control group during the hours midnight to 8am
This stud supports the cognitive approach to understand the nature of sleep in that it shows skills such as alertness , memory and performance are impaired with lack of sleep and so accidents are more likely to happen when companies employ workers on night shift

Question 9

Evidence of reorganisation theory - dolphins

Answer 9

• the spiny anteater echidna and dolphins all have a very large forebrain relative to body size- and they do not have REM sleep. The reorganisation theory would explain that this excessively large cortex is because it does not lose unwanted memories during REM sleep so needs tie capacity to store both adaptive and non adaptive memories

Question 10

Summary of evidence for the reorganisation theory

Answer 10

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Question 11

Evaluation : strengths and weaknesses of reorganisation theory

Answer 11

Strengths
+ clear about why REM is important
+ explains why pictures are in dreams

Weaknesses

• doesn’t explain non rem
• subjective evidence
• patients with PTSD often suffer repetitive nightmares , suggesting sleep doesn’t delete harmful memories
• human long term memory has un unlimited storage capacity which counters the idea it is necessary to delete memories