Psychology A2 - Sleep

  • Created by: Scarlett
  • Created on: 18-09-13 10:05

Behavioural Appraoch

Behaviour is acquired through association and the environment. (Nurture - Environmental determinism)

Classical Conditioning - Making a connection or association between a stimulus and a response

Operant Conditioning - The consequence of behaviour, influences whether or not it will be repeated.

Social Learning Theory - Introduced by BANDURA because he recognised that OC and CC rely on direct experience. SLT involves VICARIOUS REINFORCEMENT where an experience is reinforced indirectly by watching others be praised. 

Mainly use experiments and research on animals for this approach. They believe only observable behaviour should be studied.

+Objective                                  - Lab experiments = low EV

+Easily apllicable                       - Reductionist

+We do learn by association

1 of 22

Biological Approach

Behaviour can be explained by looking at biological factors in the body. (Nature - physiological determinsim)

Genes - Predispositons, concordance rates, MZ and DZ twins.

Brain Structure - Phineas Gage - bar through brain, change of personality.

Biochemistry - Neurotransmitters and hormones. Schizophrenia - high dopamine. Depression - low serotonin.

Behaviour should be studied scientifically in lab experiments. Also the use of animals which can be generalised to humans. Believe behaviour can be removed using biological treatments - drugs.

+ Scientific approach                         - Reductionist

+ Objective                                        - Drugs only work for some (Why?)

+ Applicable                                      - Only treat symptoms

2 of 22

Circadian Rhythms

Repeats every 24 hours.

Enodgenous Pacemaker - Controls from inside

Exogenous Zeitgeber - Internal control

Suprachiasmatic Nucleus - In the hypothalamus and controls the sleep/wake cycle

Melatonin - Chemical that increases before sleep.

MICHEAL SIFFRE - A french cave explorer who spent 6 months underground in a cave away from any exogenous zeitgebers. This allowed him to "free run". When he was awake, they turned the lights on, when he went to bed, they turned them off At first his sleep/wake cycle was very erratic, 25-30 hours, but he soon settled into a 25 hour rhythm suggesting that endogenous pacemakers run a little slower and is corrected a little each day by zeitgeber.

+ ASCHOFF and WEVER placed pps. in a bunker and they kept a regular cycle of between 24-25 hours.                 

Case study so difficult to generalise  - Living in a cave (cold) may have affected it

3 of 22

Circadian Rhythms - Continued

RALPH - Took a mutated SCN with a shortened 20 hour rythm from one mouse and transplanted it into another which developed a similar rhythm. 

The PINEAL GLAND works with the SCN and regulates the release of melatonin which is released during darkness and peeks at roughly 3am.

CORTISOL is another hormone that affects sleep. This is at its lowest around midnight and peeks at roughly 6am.

This can affect drugs as they are likely to be inefficent if taken at a time where the target hormone levels are low. The study of this is called CHRONOTHERAPIES.

4 of 22

Restoration Theory

Physiological patterns associated with sleep are produced by the recover processes of the body.

OSWALD - Noticed that people who had suffered severe trauma to the brain, spent more time in REM sleep. He proposed REM restired the brain while NREM restored the body.

SHAPIRO - Found that runners spent more time in NREM sleep after a marathon.

HORNE and MINARD -  Found that exhausting excerise made you fall asleep faster not longer. 

PETER TRIPP - Raised money for charity by staying awke for 201 hours. After a few days, he showed signs of mental disturbance. Hallucinations and paranoid delusions. At the end he sle[pt for 24 hours and woek up feeling back to normal and refreshed. 

RANDY GARDENER - Beat this by staying awake for 264 hours (11 days). He suffered from blurred vision, disorganised speech ad mild paranoia. On his first night of sleep, he slept for 15 hours and over and the following nights recovered 1/4 of the sleep he`d lost, 2/3 of deep NREM and 1/2 REM.

5 of 22

Restoration Theory - Continued

HORNE- Beleived REM and deep NREM are essential for normal brain function. He refers to these as CORE SLEEPLight NREM sleep appears to have no obvious function and refers to this as OPTIONAL SLEEP.

As a baby, 50-60% of sleep is REM. As older children, this falls to 25%. Young adults. 20% and by your 70s and 80s and it falls to only 10%. 

STERN and MORGANE - Thought REM sleep is for the restoration of neurotransmitters.

- It may just be that the mechanisms resposible for sleep deteriorates as we get older.

+ As you get older, you learn less so wouldnt need as much CORE SLEEP. 

6 of 22

Infradian Rhythms

Lasts for more than a day.

Menstral Cycle - 

At the beginning of the cycle, oestrogen rises causing the lining of the uterus to thickens. In the middle, ovulation takes place and an egg is released by an ovary.

If the egg is fertilised, it attaches to the uterus and develop. The average cycle is 28 days but can range from 21-35 days. 

McCLINTOCK- Studied 135 women aged between 17-21 lining in female uni halls and found the women who spent a lot of time together had synchronised cycles. He beleived that synchrony was produced by pheremones. However there is a lot of disagreement as to whether they exist. 

RUSSELL- Wanted to know if olfractory cues from one women could influence anothers monthly cycle.They collected odour by placing cotton pads in the armpits of donor for 24 hours. This pad was then rubbed on the upper lips of pps. This was carried out 3x a week for 6 months. He found that the cycles shifted significantly to resemble the donors. 

7 of 22

Infradian Rhythms - Continued

PMS occurs the week before menustration and can cause agreesion and depression.

DALTON- Found that PMS was associated in an increase in accidents, suicides and crimes. PMS has been used as legal defence. DETERMINISTIC.

Seasonal Affective Disorder - (SAD)

This is related to variations in melatonin which is produced in the night. Due to it bieng darker in winter time, this can lead to more melatonin. Phototherapy is often used to combat this by using a bright light.

POSTOLACHE- Found treatment with artifical light does not produce as complete a remission as natural sunlight. Patients scored higher on depression in winter than in summer. Temperature and social contact may also affect this.  


This can last up to 7-8 months. It involves significant changes to metabolism, heart rate and circulation. It is thought this is caused by hormones triggered by endogenous pacemakers which react to light and temperature. Animals may not hibernate if not given the appropriate clues.

8 of 22

Infradian Rhythms - Hibernation Continued

DAWE and SPURRER- Transfused blood from hibernating squireels into active oneswhich fell into hibernation 48 hours later. There is a chemical in the blood called HIBERNATION INDUCTION TRIGGER (HIT).


9 of 22

Jet Lag

This occurs when we cross time zones due to the shift in zeitgebers. Our body is telling us its one time and the environmental cues are saying its another. 

East to West is best, it causes a PHASE DELAY wheres its just like going to bed earlier.

West to East causes a PHASE ADVANCE where you feel as though youre waking up earlier. This is harder. 

RECHT- Looked at US baseball players who travelled a lot for games. The US is larger enough to have 4 different time zones. They studied the results over 3 years and found that teams travelling East to West before a game, won 44% of their games compared to those travelling West to East who won 37%. However there was no control over the behaviour of the players before the game and it dosent consider the influence of the coaches. 

Jet Lag and Cancer-

RAFRISOON-  Used data from 1500 female flight attendants and found that those who had been flying for over 50 years ahd double the risk of breast cancer.

10 of 22

Jet Lag - Continued

FILIPSKI - Recreated the effects of jet lag in mice by repeatedly phase advancing the light/dark cycle by 8 hours every 2 days. They found that the desynchronised animals experinced accelerated cancer tumour growth.

You can help this by sleeping whien it`s night and staying awake during daytime. 

BEAUMONT- Found that taking melatonin tablets for 5 days after arrival significantly reduced the symptoms of jet lag. Though the long term consequences havent been fully investigated. 

11 of 22

Shift Work

Working in scheduled slots.

The more taxing ones are those that go against the bodys natural inclination to adapt to a longer day. Should rotate shifts clockwise

Night shifts are especially hard as your body tells you to sleep. This also means you then have to sleep during the day hien it`s light and noisy, they get one average 2 hours less sleep. The exposure to light messes with the melatonin levels which can take 2 weeks to right.

CHARLES CZEISLER- Studied shift patterns. Health problems, sleep difficulties and work related stress were noted. The pahse delay system waschanged, moving a shift forward. He also changed shift roatation from 7-21 days allowing more time for adjustment. After 9 months, work satisfaction was significantly increased and factory output was higher.

+ High Ev

-Other factors may have affected it (personality)

12 of 22

Evolutionary Theory

Sleep has evolved into essential behaviour because it provides some selective advantages. 

Unilateral Sleep-

An arguement against this is that sleep is foudn in animals that would be better off without it. The Indus river dolphin has adapted to become blind where there is poor visability yet, despite being at risk of being hit by floating debris or attacked, it still sleeps. However it does this in 4-60 second naps that accumulate to roughly 7 hours a day. This and hibernation resemble SWS. 

The pattern differs from one species to another. In this, one hemisphere is asleep while the other is awake. In dolphins this is important in order for them not to drown so the hemispheres swap every 2-3 hours. 

Species that have more similar patterns are genetically close <- Strong Phylogenetic.

13 of 22

Evolutionary Theory - Continued

WEBB -  Claims the function of sleep is similar to that of hibernation. It serves to preserve energy at a time when it would be inefficent to be awake.

BERGER- Believed sleep helps to offset the cost of being endothermic (warm blooded). It helps reduce metabolic pressure. Have a rate up to 10x greater than ectothermic animals (cold blooded). 

ZEPELIN - Found a correlation between diet and sleep. Herbivores sleep the least while carnivores sleep the most. Omnivores fall in the middle.

RATTENBORG - Attached EEG`s to 3 toed sloths and monitored them for 3-5 days. He found they slept an avaerage of 9.63 hours a day, 6 hours less than captive sloths. This may be because they have to be more cautious of predators and spend more time foraging. 

14 of 22

Evolutionary Theory - Predation

Predation Theory-

Suggests sleep is a survival advantge.

Night time is dangerous for diurnal animals who have poor night vision. Others may evolve to sleep in burrows and grazing animals sleep very little.

ALISON and CICCHETTI- Found an analysis of the sleep patterns of 39 species revealed a relationship between risk of predation and amount of sleep. However there were exceptions suggesting this theory may only apply to some animals. 

This theory dosent explain why we have a strong urge to sleep when sleep deprived.

HORNE- Believes there is a distinction between core and optional sleep. Core sleep = Stage 4 and REM sleep and is vital to keep normal brain funtioning. Optional sleep = portions of NREM (is dispensible), Optional sleep has the function of occupying unproductive hours and in small mammals, of conserving energy. 

15 of 22

Sleep Disorders - Insomnia

Insomnia - 

Whether or not you feel refreshed following a nights sleep. May involve *Trouble falling asleep * Remaining asleep * Waking too early. Can be either short term, occasional or constant and long term for over a month. 

Usually associated with increases in a number of physiological measures over a 24 hour cycle such as body temperature, heart rate and metabolic. Researchers believe insomniacs are in a state of hyper arousal.

VGONTZAS - Found that insomniacs have increased levels of adreno-cortizotrophic hormone (ACTH) and cortisol, both of which are linked to stress and arousal. 

NOFZINGER - Found insomniacs had a smaller decline in brain stem and pre-frontal cortex activity at night. 

16 of 22

Sleep Disorders- Insomnia Continued

Personality - 

HALES- Used a personality test (Minnesota Multiphasic Personality Inventory) to test a sample of insmniacs and non-insomniacs. The insomniacs had personality traits in common. They tended to handle stress and problems internally rather than expressing emotions.

Genetics - 

WATSON - Found evidence of possible predisposition. He found that MZ twins insmnia was highly correlated at 0.47. DZ insmnia was poorly correlated at 0.15. Genetics may have a strong influnce on the disorder.

JOHO- Studied mice which displayed behaviour very similar to human sleep maintenance inssomnia. He found that mutations in the genes that control electrical excitabiliy in the brain area controlling SWS cause the mice to enter SWS for only short periods before waking up. 

+Mainly Bio/Physio Approach  -Reductionist

+Easily Replicated                    -Chronic insomia highly complex. 

17 of 22

Sleep Disorders - Sleepwalking

Can wander around from a few seconds to half an hour. When woken they experience mental confusion. Around 30% of 5-12 year olds may have episodes of sleepwalking but in only 1-5% does it ocur regularly. Tends to run in families. Usually takes place in deeper stages of NREM early in the night. During sleepwalking, they usually carry out routine automatic tasks but can sometimes be quite complicated. 

A disorder of imcomplete arousal. EEG recordings show a mixture of Delta waves typical of SWS plus Beta waves which are characteristic of being awake.

BAKWIN- Studied the frequency of sleepwalking in MZ and DZ twins and found a CR of 47% for MZ`s and 7% in DZ`s. He also found a tendency within families. 

BASSETTI- Believes it may be related to the same gene abnormality associated with narcolepsy.

OLIVIERO- Believed sleepwalking may be more common in children because they have more SWS. He suggested the system that normally inhibits motor activity is not sufficently developed in some children and adults. 

18 of 22

Sleep Disorders - Sleepwalking Continued

Jules Lowe attacked and killed his father but claimed no recollection because he was sleepwalking. Tests were carried out and they observed him during his sleep. He had a history of sleepwalking but had never been violent. The test proved he did sleepwalk and he was diagnosed with INSANE AUTOMATISM (which is linked to drinking). He was found not guilty due to insanity. 

19 of 22

Sleep Disorders - Narcolepsy

2 main symptoms are feeling sleepy and episodes of cataplexy (loss of muscle tone) during the day. These are triggered by emotional arousal. Begins in adolescene or early adulthood. 1 in 2000 people are sufferers.


20 of 22

Sleep Disorders - Narcolepsy Continued


SCAMMELL- The neurotransmitter hypocretin has an important role in maintaining a waking state of mind. Scammell suggested that narcolepsy is caused by the loss of cells in the hypothalamus that secret HCRT. 

GERASHCHENKO- Found evidence for the role of the hypothalamus in narcolepsy by developing cells in the hypothalamus in rats with a neurotoxin. They found a relationship between the number of cells lostand a decline in levels of HCRT. A 73% decline in HRCT neurons resulted in a 50% reduction in HCRT. As narcoleptics have 80% less HCRT, this suggests that some nuerons are lost. 

THANNICKAL- Conducted post-mortem analyses of the brains of parkinson sufferers and found that the brains had lost up yo 62% of the vell that contain HCRT. 

Genetic Explanations - 

Narcolepsy has been found in certain breeds of dog. Research had found that Doberman Pinchers have a genetic mutation affecting HCRT but unfortunately, further research indicated this genetic defect did not apply to humans.

21 of 22

Sleep Disorders - Narcolepsy - Genetic Explanation

Seems unlikely that narcolepsy in humans is purely genetic because narcolepsy does not run in families and insnt concurrent in twins. It is thought it is caused by a combination of genetic predispositon and one or more environmental factors such as hormonal changes, infection, trauma or immune system dysfunction.

Narcoleptics have increased frequency of one type of leukocyte antigen. HLA which could link to HCRT neurons being destroyed as part of the autoimmune response. HLA is part of the immune system and recognises foriegn antigens. However the most specific HLA variant is not found in all narcoleptics. 

22 of 22


No comments have yet been made

Similar Psychology resources:

See all Psychology resources »See all Sleep resources »