Psychology A2

• Seen in all complex animals, if deprived they try and catch up.
• Adults have spent 1/3/ 25 years of life asleep.
• Sleep itself ultradian rhythm with cycle of 90-120 minutes
• sleep-wale cycle circadian rhythm
• altered state of consciousness but no unconscious. 
• Part of Hypothalamus called Suprachiasmatic nucleus SCN acts like master clock to control sleep reacting to light from optic nerve and influencing pineal gland to produce melatonin.
• Little known until 1930's when scientists used EEG to measure electrical activity in the brain.
• Divided into 2 categories NREM & REM
• Order of stages 123432 REM (one 90 minute cycle) repeated aprox 5 times during night.

• Period of light sleep, brain waves start to slow down, HR slows down & muscles relax if you were woken you'd probable not be aware of sleep at all. 
• Length: 10-15mins
• Hertz/Waves: 8-12 Hz Theta

• Brain waves slower and short bursts of brain activity (sleepspindles) also K complexes.
• Length: 10-15 mins
• Hertz/Waves: 4-8 Hz Theta

• Large slow waves appear. Brain waves and body activity slow down even more. 
• Length: 15 mins
• Hertz/Waves: 1-4 Hz Delta

• Waves mainly delta. Other than occasional twitches person very still. Very deep sleep and difficult to wake up. Growth hormones produced and sleepwalking takes place. 
• Length: 30mins
• Hertz/Waves: Delta

• Eyes move rapidly and muscles paralysed. EEG shows brain very active. very difficult to wake someone if woken often report they were dreaming. Sometimes called paradoxical sleep because of contrast between active brain and unresponsive sleeping body.
• Length: 10 mins in first cycle & builds through night
• Hertz/Waves: 13-30 Beta

Normal working thought

light sleep

Deep Sleep.

• Sleep labs-studied objectively & scientifically
• REM and Dreams- thought to be same thig but dreams don't always occur in REM.

• sleep about 16-18 hours a day 50% in REM
• Premature babies REM can be up to 80%
• by 20 weeks babies useually awake between 10am & 8pm

• by 5 children have EEG patterns
• Sleep about 12 hours a day
• Have more REM activity
• Boys sleep more than girls
• Not uncommon for children to experience parasomnias

• Need for sleep decreases slightly
• Phase delay
• sleep patterns vary according to school year
• students who achieve mostly A's in their grades went to bed earlier & slept on average an hour longer.

• 2007
• sleep
• Adolescence lifespan changes
• sleep patterns & school year

• sleep
• Adolescence lifespan changes
• 3000 high school students

• 8 hours a night 25% REM sleep
• parasomnias rarer
• increase in other sleep disorders

• more difficulty going to sleep
• waking up more common
• REM decreases to 20% 
• deep NREM decreases from 24% in childhood to 5%
• Phase advance

• some ages researched more than others
• Gender differences
• Methodological problems
• Sleeping with a partner
• individual differences & age
• Operationalisation of sleep
• Cultural traditions

• Sleep
• Some ages researched more than others
• middle aged people

• Sleep
• Individual differences & Age
• sleep patterns determined by individual characteristics

• Sleep
• Oswald 1980
• Horne 1988
• Oh...

• Sleep
• Restoration theory
• Brain repair
• Immune System
• Tissue repair/Growth hormone
• Neurotransmitters
• REM essential for Brain repair
• NREM essential for Body repair

• Sleep
• Restoration Theory
• Oswald 1980
• People with brain traumas spent more time in REM
• Babies spent more time in REM for brain growth

• Sleep
• Restoration Theory 
• Oswald 1980
• Lack of sleep reduces function of immune system

• Sleep
• Restoration theory
• Oswald 1980
• new skin cells grow quicker during sleep
• Growth hormone released in stage 4

• Sleep
• Restoration Theory 
• Optional & Core Sleep
• REM and deep NREM used for restoration of the brain
• Light stages of NREM useless could be missed out
• Body repair can happen in relaxed wakefulness

• Sleep
• Oswald & Horne 
• Sleep Deprivation studies
• Exercise  & sleep
• Other evidence/AO2

• Restoration theory
• Case Studies
• Studies with animals
• human fatal familial insomnia

• Restoration theory 
• Peter Tripp 
• Randy Gardener 1965

• Sleep
• Restoration theory
• Sleep Deprivation case study
• Didn't sleep for 8 days
• Hallucinations & Delusions 
• Abusive & Paranoid
• Supports

• Sleep
• Restoration theory
• Sleep Deprivation case study 
• Didn't sleep for 11 days
• difficulty performing some tasks
• nothing like problems of Tripp
• Few physical symptoms
• Took 15 hours to catch up
• No permanent effects
• More typical 
• Goes against

• Restoration theory
• Rechstaffen et al 1983
• Rats on disks over water 
• One sleep deprived 
• All sleep deprived died after 33 days
• Supports

• Sleep 
• Restoration theory 
• Sleep Deprivation 
• Rare inherited condition 
• Sleep until middle age then stop
• Man studied died within 2 years 
• Supports BUT...
• Impossible to separate effects of sleep dep from underlying brain damage.

• Restoration theory
• Micro sleep 
• Stress
• Using animals
• correlational
• Case studies
• Lack of validity

• Restoration theory 
• Evaluation of sleep dep
• Cases of Tripp & Gardener little control over them 
• Lab studies would've used EEG recordings to monitor them
• May be they had periods of micro sleep

• Sleep 
• Restoration theory
• Evaluation
• studies on non humans show sleep dep leads to death
• very stressful procedures used
• impossible to separate effects of stress from sleep dep.

• Restoration theory
• Different sleep requirements & patterns
• Generalisabilty limited
• Ethical issues many animals died

• IV not manipulated
• No cause & Effect
• Lacks conclusiveness

Participants likely to be unique

• Total sleep dep very rare in real life 
• Even insomniacs sleep around 6 hours
• Sleep dep in a lab even less realistic.

• Restoration theory
• Predict More sleep
• Shapiro et al 1981
• Horne and Minard 1985

• Sleep
• Restoration theory
• Exercise and sleep
• Marathon runners
• Slept 1 hour more 2 nights following race
• Supports Oswald 1980

• Sleep
• Restoration theory
• Sleep & Exercise
• After many exhausting tasks ppts slept quicker but not longer

• Face Validity
• Neurotransmitters
• Studies of animals
• Issues and Debates

Makes Sense

• Suggested restored in sleep
• REM sleep brain very active
• More likely used up than restored

• Amount of sleep needed by animals varies can't explain this
• Nor why animals need to be unconscious for repair.

• Nature not nurture
• Biological approach- No free will to change patterns - not true for shift work.
• Reductionist ignores culture & learning.

• Behaviours evolve to help animals survive
• Explains why animals have different amounts

• Sleep
• Evolutionary theory
• Foraging
• Avoid Predators
• Sleep Site
• Environment- Land/Water

• Sleep
• Evolutionary Theory
• Herbivores eat food poor in nutrients must eat a lot to get full so less time to sleep
• Carnivores eat food high in nutrients don't need a lot so afford to sleep more

• Sleep
• Evolutionarytheory 
• Predators can sleep longer
• Prey remain awake for enemies
• Really shouldn't sleep at all but if sleep necessary makes sense when least vunrable

• Sleep
• Evolutionary theory
• If safe deep burrow they can sleep more

• Sleep
• Evolutionary theory
• Animals in water difficulty breathing & sleeping
• If dolphin fell into deep sleep it would drown
• Evolved so 2 hemispheres of the brain swap over every 2-3 hours. (Unilateral)

• Waste of time (Meddis)
• Saving Energy Webb hibernation theory 1982

• Sleep
• Evolutionary explanation
• Meddis
• Sleep keeps animals safe when normal activities impossible
• Sleep 'Waste of time' keeps animals away from predators
• Ensures animals stay still usually hidden
• Allison & Cicchetti 1976

• Sleep 
• Evolutionary Explanation
• 1976
• Studied sleep in 38 animal species
• Prey animals slept significantly less
• Goes against Meddis
• Prey often Herbivores (Foraging)

• Sleep
• Evolutionary explanation 
• Sleep leaves animal vulnerable & unable to respond to danger
• If safety most important more effective to stay awake but quiet 
• Noisy sleepers particularly unsafe

• Sleep
• Evolutionary explantion
• 1982
• Animals hibernate in winter when activities impossible
• Sleep time of inactivity animals conserve energy resources
• Particularly important for small animals as high metabolic rate
• Small animals sleep more to conserve energy.
• Berger & Phillips

• Sleep
• Evolutionary Explanations
• Saving Energy Webb's hibernation theory
• Basal metabolic rate (rate which animal burns energy) positively correlated with sleep time
• smaller animals higher BMR so sleep more
• Only NREM useful to conserve energy
• REM energy consumption slightly less than working behaviour

• Exceptions
• Why haven't we evolved to need less?
• Problems with finding data on animals
• Correlations
• Deterministic & Reductoionist

• Sleep 
• Evolutionary Theory AO2
• Some animals don't sleep as theory would predict
• Giant sloth large & Inactive shouldn't need much sleep but sleep 20 hours a day
• Rabbits & moles sleep 8 hours yet rabbits higher danger rating.

• Sleep 
• Evolutionary Theory AO2
• Energy Conservation improtant in past
• Today huge advantage if survive on less sleep
• This has not happened

• Sleep 
• Evolutionary Theory AO2
• Young 2008 out of 5000 species info on less than 150
• data often based on fewer then 5 animals
• Often in lab conditions may not be reliable
• Know even less about REM/NREM patterns

Ignores free will, says it can't be changed and we can't be punished. Any evolutionary or Biological explanations.

Too Simple, things far more complicated processors, doesn't take into account other theories.

• Dysomnias
• Parasomnias
• Insomnia
• Sleep Walking
• Narcolepsy

Problems with quality, amount or timing of sleep

Behavioural or psychological events that happen in sleep.

• Sleep Disorder
• Lack of sleep 
• Initial insomnia-Problem with falling asleep
• Middle Insomnia-Problem with staying asleep
• Terminal insomnia-Problem with waking up too early
• Not defined by number of hours asleep

• Primary Insomnia
• Secondary Insomnia

• Insomnia occurs with no obvious medical or psychological cause for over a month.
• Idiopathic Insomnia
• Circadian Rhythm disorder

• When insomnia is result of existing physical or psychological condition. Symptom of other problem.
• Physical complaints
• Psychological conditions
• Stress or anxiety
• Medication
• Parasomnias
• Faulty learning

• Rare (1%) form of insomnia 
• no obvious explanation of cause
• Begins in childhood is lifelong
• Doesn't vary with life circumstances
• Likely to be some basic malfunction in our sophisticated sleep control system
• May be genetic some evidence it runs in families

• Dauvilliers et al 2004
• Watson et al 2006 Twin studies 
• Biological approach deterministic, can't overcome problem. However good sleep hygiene & treatments mean difficulties can be overcome.
• Reductionist complexity of many types of insomnia. ignores learned factors.

• Sleep
• Sleep Disorders
• Idiopathic insomnia evaluation 
• 2004
• used clinical interviews/questionnaires.
• 73% of chronic insomniacs reported family history of it.
• control group who suffered occasional bouts 24%.
• Questionnaires/Interviews- researcher bias/demand characteristics

• Sleep 
• Sleep Disorders
• Idiopathic insomnia 
• 2006
• Twin studies
• correlation 0.5 in MZ twins 0.15 in DZ twins
• Suggests genetic explanation
• Identical twins treated similar could be enviroment.

• persons biological clock/sleep-wake cycle not synchronised with 24 hour light/dark environment.
• Shift work or jet lag 
• Barion & Zee 2007 AO2
• Teenagers- Roberts et al 2008 AO2

• Sleep 
• Sleep Disorders
• Circadian rhythm disorder AO2
• 2007
• Clinical trials
• Common symptoms insomnia & excessive wakefulness
• lead to Multimodal approach to explaining primary insomnia
• development of successful intervention programmes (bright light, hormone replacement therapy)

• Many teenagers suffer probably due to hormones
• Phase delay
• Roberts et al 2008 AO2

• Sleep
• Sleep disorders
• Circadian rhythm disorder
• Teenagers 
• 2008
• Texas
• 25% reported insomnia 
• 5% said interfered with ability to do things next day
• Led to suggestion schools open later in morning.

• Face validity
• Methodology
• Gender differences 
• Many Factors
• Belief 
• Treatments
• Roth

• Self report not all anonymous
• Not possible to know how accurate or if ppts were influenced by what they thought socially desirable
• Mostly correlation

• Doesn't explain why women suffer more 
• Women have higher levels of anxiety or neuroticism or due to hormonal changes
• Findings inconsistent
• Few studies look specifically at gender differences

• Chronic insomnia highly complex unlikely to be explained by 1 factor
• Large number of factors make it hard to conduct meaningful research
• studies only find small effects 
• Difficult to draw firm conclusions

• Main causes persons belief they're going to have difficulty sleeping
• person is tense when trying to sleep

• Important to distinguish between primary & secondary for treatment needed.
• If insomnia symptom of other disorder important to treat that first

• Sleep
• Sleep disorders
• Primary insomnia
• Doesn't think it's common
• claims 10% of insomniacs have primary insomnia.
• 90% have secondary cause.

• Secondary Insomnia
• Medical Conditions
• Diabetes
• arthritis
• asthma

• Secondary Insomnia
• Depression 
• Schizophrenea
• generalised anxiety disorder

• Worrying causes anxiety which can cause insomnia
• Not sleeping causes fustration & even more anxiety
• Vygontas et al 2001

• Sleep 
• Sleep Disorders
• Secondary insomnia
• 2001
• Compared patients with insomnia to those who didn't suffer
• insomniacs secreted more cortisol 
• Suggests chronic insomnia involves sustained arousal of body's stress response system

• Secondary Insomnia
• Some Medication side effects which disrupt sleep
• Medication taken to improve sleep cause problems if effects too long lasting.

• Sleepwalking disrupts sleep 
• Sleep apnoea repeated awakenings 
• Obstructive sleep apnoea where person stops breathing while asleep may occur 5-30 times an hour.
• For safety brain wakes person up
• OSA highly correlated with obesity 
• Krakow 2009

• Sleep 
• Sleep disorders 
• Secondary insomnia
• Parasomnia
• 2009
• believes more than half patients who report chronic insomnia have undiagnosed sleep apnoea.

• Secondary insomnia
• Behavioural approach claims insomniacs have faulty learning
• My eat, watch telly or listen to music in bed
• Brain associates bed with being awake & active
• Person difficulty falling asleep

• Sleep 
• Sleep Disorders 
• Secondary insomnia AO2 
• 2006
• Aim- see how family conflict affected later development of insomnia. Longitudinal study
• Procedure- New Zealand, Children followed from birth 1972 to present day. Wide range of things studied. One variable family conflict. assessed using questionnaire to measure levels of tension, hostility & distress in family. included events such as separation & divorce.
• Results- Degree of family conflict between 9-15 was correlated with insomnia at 18. controlled factors such as socio-economic status, gender, health & depression.
• Conclusion- Possible causal connection between family conflict & later sleep problems.

• Methodology- large study over 1000 children on 15% suffered insomnia aged 18, majority female. Relatively small group to study effects of so many variables. Study Correlation.
• Ethics- Study began when children born so informed consent needed from parents then themselves when 16. Info collected from intrusive personal questions. Would've had right to withdraw. Researchers gained full ethical approval.

• Parasomnia
• Most common in childhood
• affects 20% of children less than 3% of adults
• Usually takes place in stage 4 of sleep 
• Do things usually performed in day
• Not conscious & later has no memory of events.

• Genetic factors
• Psychodynamic explanations
• Environmental Factors
• Physiological factors

• Strong evidence for genetic basis
• Hublin et al 1997-twins
• Kales et al 1980-parents percentage
• Researchers identified a gene DQB1*05 may be crucial in SW & night terrors

• Sleep 
• Sleep Disorders
• Sleepwalking 
• Genetic Factors
• 1997
• large scale questionnaire
• 11,220 identical & non-identical twins
• Greater chance both identical twins were sleepwalkers.

• Sleep 
• Sleep disorders
• Sleep Walking
• Genetics
• 1980
• child is 10 times more likely to suffer if first degree relative does
• Percentage of Sleepwalking increases from 45% if one parent is affected to 60% if both parents are.

• Not 100%
• Biological model
• nature not nurture 
• no free will
• problems with twin studies
• large sample

• Freud thought SW linked to dreaming
• during dreams work through unconscious anxieties
• Moving from REM to NREM stops this so unconscious energy spills into NREM.
• SW is person acting out their dreams
• Represents desire to sleep where person slept as a child
• Doesn't explain wide range of acts SW displays

• Don't lead to hypothesis that can be tested using objective scientific methods
• Whether you believe or not becomes matter of personal opinion
• Arnulf et al 2009 matched SW to dreams

• Sleep 
• Sleep disorders
• Sleepwalking 
• Psychodynamic AO2
• 2009
• Matched 43 patients with severe SW with control group of 25 healthy patients
• Data gathered retrospectively by interview
• Sleep patterns monitored over 1 night in sleep lab.
• 71% ppts reported at least 1 dream which associated with an episode of SW 
• Researchers noted action in dream corresponded with observed behaviour in sleep lab
• Controlled experiment in lab- more valid
• Definition of dreaming vague
• data gathered retrospectively may not be reliable.

• Sleep deprivation
• fever
• effects of drugs & alcohol
• Hormonal changes
• Menstruation
• Zadra et al 2008-SW after sleep dep

• Sleep 
• Sleep Disorders
• Sleepwalking
• Environmental factors
• 2008
• 40 patients 
• Observed in sleep lab
• behaviours such as playing with bed sheets, sitting up & walking around counted
• Observed for a normal nights sleep then returned to sleep lab & deprived from sleeping
• after 25 hours allowed to sleep 
• First night 50% sleepwalkers showed signs of SW
• After sleep dep rose to 90%
• Sleep dep doesn't lead to SW in normal individuals must be characteristic of people genetically predisposed to SW
• May provide useful way of diagnosing condition
• Repeated measures in lab well controlled, results reliable.
• may not sleep normal in lab-lacks ecological validity
• May be genetic vulnerability but environmental triggers  also needed.

• Hormonal changes
• Menstruation 
• SW may be more common in children as they spend more time in stages 3 &4.
• AO2- Nature not nurture, deterministic, Biological approach.

• SW hard to test as not predictable
• In lab people wired up to electrodes & woken frequently not typical of sleep so can't be generalised.

• Free will or deterministic?
• People accused of murder/rape claim they were sleeping.
• Jules Lowe tried for murder in 2003 claimed couldn't remember committing crime claimed must have been SW. Found 'Not Guilty' but indefinitely secured in psychiatric hospital.
• Kenneth parks drove 14 miles stabbed mother in law. jury usually find motive or conclude actions too deliberate to be SW. however jury accepted his case.
• Brings up debate of free will

• Sleep disorder characterised by excessive daytime sleepiness. 
• addition people often have symptoms such as cataplexy, disturbed night time sleep, hallucinations & sleep paralysis.
• Begins in adolescence 
• Estimates suggests affects 1/2000

• Differences with the brain
• Genes
• Psychological explanations

• first put forward in 1916 Von Economo suggested narcoleptic patients had damage to hypothalamus & midbrain.
• Fault in part of brain that control REM sleep
• Explains some of classic symptoms e.g. cataplexy same in REM sleep
• REM associated with dreaming & loss of muscle tone
• People with narcolepsy have loss of muscle tone & go into REM very quickly.

• Too Simplistic-doesn't explain daytime sleepiness
• Evidence narcolepsy caused by brain damage rare
• recent case 23 year old got narcolepsy following damage to his hypothalamus after a stroke.
• Another person got it as result of tumour

• Researchers noticed some dogs suffered from cataplexy, especially when excited.
• Tendency can be increased by selective breeding allows narcolepsy to be studied directly.
• Gene defect responsible for narcolepsy in dogs
• Gene on chromosome 12 responsible for regulating neurochemical called orexin.
• Confirmed by Thannickal et al 2000-studied brains of narcoleptics.
• Injecting Orexin into areas of brain involved in sleep increase REM suggestion orexin centrally involved in control of REM sleep.

• Sleep 
• Sleep disorders
• Narcolepsy
• Genes 
• 2000
• examined brains of 4 narcoleptic patients who'd died 4-12 years earlier 
• Found orexin producing cells in hypothalamus were drastically reduced in people with narcolepsy compared to 12 normal people brains.

• Chemelli et al 1999 mice that couldn't make orexin developed symptoms of narcolepsy.
• Studies with animals can't be generalised. Bring up ethical issue genetically manipulating animals to develop unpleasant disorders but generated much useful research
• Can't explain why some people have less orexin. MZ twins have higher concordance than DZ but only 30%. suggesting not entirely inherited.
• Drugs to increase orexin not yet available .
• Most agree narcolepsy involves genes & at least 1 environmental trigger.

• Most explanation biological some failed attempts at psychological
• Lehrman 1943 suggested sudden attacks of sleepiness disguise sexual fantasies.
• Little evidence to support & very difficult to test in objective way in a lab.

Occur every 24 hours

Have cycle length of more than one day

occurs more than once every day

• Sleep wake cycle
• Body temperature
• Hormones

• one period of sleep & wake every 24 hours
• average person 7 hours a day
• Usually unbroken period of sleep 
• Some countries siesta normal
• In humans cycle controlled by endogenous pacemaker called suprachiasmatic nucleus (SCN) pair of cells in hypothalamus
• Also effected by external causes exogenous zeitgebers eg light

• Lowest about 4:30am
• Highest around 6pm
• Slight trough after lunch not due to effects of eating.
• Many countries siesta is related to this dip
• Folkard et al found children remember more material in afternoon when body temp higher.

• Concentration on hormones varies over the day
• prolactin peaks in middle of night explains why women often go into labour then.

• Menstrual Cycle
• Seasonal affective disorder (SAD)

• Happens aprox every 28 days 
• Controlled by internal biological clock 
• Mainly endogenous 
• can be influenced by exogenous cues.
• Research shown when many women live together they menstruate at same time.
• Some evidence for cycles in men Empson 1977 looked at temp & mood in males & found a cycle of aprox 20 days
• PMS also affects many women a week before menstruation. symptoms: acne, depression, mood swings

• Form of depression affects people in winter months
• People tend to eat & sleep more in winter
• Serotonin & Melatonin secreted when its dark by pineal gland
• Research shows these hormones are a cause of chronic depression
• Understanding role of darkness in SAD led to effective treatment.
• Phototherapy uses very strong light to suppress melatonin
• Some question if due to placebo effect.

• Sleep Stages 
• Oral Habits

• 5 stages of sleep in one cycle
• One sleep cycle goes through al 5 stages & lasts about 90 minutes
• Cycles continuous through the night with REM stages getting longer as night progresses
• cycle noted in foetuses as young as 20 weeks
• control of cycle is through variety of neurotransmitters 
• Biological clock in Medulla seems to control number of 90 minute cycles

• Eating occurs roughly at 4 hour intervals
• Smoking & coffee drinking cyclic due to need to sustain stimulant effects 
• Animals fed at particular times reliably increasing activity just prior to eating
• Friedman and Fisher 1967

• Sleep 
• Ultradian Rhythms
• Oral Habits
• 1967
• Observed eating & drinking behaviour in psychiatric patients over periods of 6 hours   
• detected clear 90 minute cycle in eating & drinking.

• Individual differences
• Biological Approach
• Real world applications
• Deterministic

• wide variation in how long people sleep
• innate difference in when circadian rhythms peak

• research in area helpful in knowing best time to take drugs
• if drugs work on certain hormones important to know when they're at their peak

• internal biological clocks
• Main one in humans SCN

External cues from Environment influence bodily rhythms

SCN- mammals main endogenous pacemaker. Runs without any external cues receives info from eyes via optic nerve, makes sure internal clock tuned into night/day.

Pineal gland & Melatonin - SCN then send messages to pineal gland to control amount of melatonin produced. At night melatonin increases as it increases we feel sleepy.

• Michael Siffre 1975: Research on sleep-wake cycle
• Method: Spent 6 months living in cave in texas
• No light or anything else to say what time of day it was
• Rhythms became free running
• When awake lights were turned on
• Wired up so some body functions could be recorded
• only telephone link to outside world, monitered by video camera
• Results: Fairly erractic sleep-wake pattern at first
• Setteled down to average of just over 25-32 hours
• Body temp more stable
• sleep & body temp became desynchronised shows 2 seperate body clocks controlling them
• Conclusion: People have endogenous cicadian rhythm to control Sleep-wake cycle. Light is needed to fine tune length of cycle & keep rhythms in tune with enviroment.

• Methodological: 
• Case study difficult to generalise
• Other studies have confirmed results
• Although isolated from clocks, radio, daylight ect not isolated from artificial light, research suggests this may affects rhythms
• Ethical:
• Volunteer fully aware of nature of study
• No one could predict effects on him 
• Did report feelings of depression, suicide & memory problems

• Stephan and Zucker 1972
• Rats housed in lab 12 hours of dark followed by 12 hours of light
• Drank more & more active when dark
• Damaged SCN of one group found didn't have normal circadian rhythms of drinking & activity

• More scientific & controlled than Siffre. Other parts of hypothalamus damaged to show didn't affect rhythms. Surgical procedure difficult 11/25 rats survived. operation itself might've affected rats behaviour
• Findings can't be generalised 
• Unethical 
• Told us useful information 

• Took SCN from golden hamster with shortened circadian rhythm of 20.2 hours
• Transplanted it into hamster with normal 24 circadian rhythms.
• Found hamster had very similar rhythms to donor

• Foetuses-regular rhythms as young as 20 weeks likely to be innate
• Biological
• Reductionist

• Light: most important zeitgeber, light can reset SCN & pacemakers in other parts of body
• Social cues: eat & sleep at times appropriate for age & culture.
• Temperature: Entrained by temperature 

• Campbell & Murphy 1998:
• studies 15 healthy volunteers in sleep lab ppts randomly put into control or experimental group. second night experiment group had light shone on back of knees for 3 hours. core body temp & levels of melatonin shifted by up to 3 hours. Suggests light has influence.
• Evaluation: Levels of melatonin for control group weren't recorded for comparison. not able to repeat findings.

• Miles et al 1977:
• Studied man blind from birth with 25 hour sleep/wake cycle despite exposure to clocks & radios. Suggests light dominant time cue.
• The Arctic:

In summer in arctic when sun doesn't set residents still slept for 7 hours a day. Suggests other factors apart from light act as zeitgebers

• Link to cancer: If artificial light resets body clock fact we live in artificially lit world may have negative consequences. Stephans says might explain why women in industrialised societies are more likely to develop breast cancer
• Not really Two Seperate Systems: although researchers try and study systems seperate, two systems run together & depend on each other.

• traditional pattern 3 8 hour periods rotate backwards after a week
• some work schedules more disrupting than others 
• Most difficult go against body's natural inclination to longer day of 25 hours.
• Fixed work schedules considered best as allow to adapt
• If shifts rotate better in clockwise direction

• Effects on health: heart disease, kidney disease & cancer associated with shift work. People who work shifs for 15 years 30% more likely to develop heart disease.
• Accidents: Most disastrous industrial accidents occur during early hours. 20% shift workers report falling asleep during work, increases risk. Most lorry accidents happen between 4-7am.
• Poor quality sleep: difficult to adjust to daytime sleeping. Typically 1-2hours shorter than night time sleep REM particularly affected
• Social Problem:difficult to meet friends & spend time with family

• Can be improved:
• Utah chemical plant backward shift rotation change every 7 days. 
• Introduced forward shift pattern 21 days on shift allow body to adjust.
• After 9 months workers reported feeling less stressed with fewer sleep difficulties & increased productivity
• Philadelphia police officers moved from backward shift rotation to 18 days forward rotation. 30% reduction sleeping on job & 40% fewer accidents.
• Although planned naps shown to reduce tiredness & improve performance not popular with employees
• Individual Differences: people deal better than others.
• Western approach: Much research done in west may be different in different cultures can't generalise
• Sampling: People willing to take part likely to be quite motivated especially when being watched. real life may behave different so may lack ecological validity.

• effects of air travel over number of time zones
• body telling us one time environment telling us other. 
• Worst traveling West to East easier to adjust body clocks when ahead of local time (phase delay) 
• No jet lag traveling North to South as no change in time zone
• although SCN can change & readjust in day effects can last up to a month because different internal clocks readjust at different speeds

• Show wide range of symptoms: tiredness, clumsiness, concentration problems, memory difficulties, digestive problems.
• Main problem disturbed sleep 
• Need about a day to adjust to each time zone crossed

• Recht et al 1995: 
• Analysed results of USA baseball league
• over 3 years studies 19 teams
• Found teams from west travelling east had fewer wins (37%) then east travelling west (44%)
• Rafnsson et al 2001:
• suggests jet lag contributes significantly to cancer
• Looked at 1500 female flight attendants found those flying over 5 years had double risk of breast  cancer. disagreement of cause of problem, correlation studies no cause & effect 

• Other factors: jet lag not just due to disruption of rhythms (travel to airport, cramped positions,noise,alcohol)
• Individual differences: some people more resistant to effects than others (Phase Tollerance)
• Age: Jet lag decreases with age
• Affects can be reduced:
• Avoid alcohol & caffine
• Melatonin
• Social customs
• Go into daylight as soon as possible

Behaviour rewarded likely to be repeated

• watching role models & imitating behaviour
• Vicarious reinforcement (seeing what happens to others)

• Similar to themselves in age & gender
• Individual has low self esteem
• Model has desirable characteristics e.g. rockstar

Attention: Must notice aggressive model

• Retention: Must remember behaviour
• Reproduction: Must have skills to copy behaviour
• Motivation: Must have good reason to copy aggression 
• Self Efficacy: Child's confidence in self to carry out aggressive act

ARRMS

• ppts male & females aged 3-5.
• half watched adult model being aggressive to bobo doll half watched non aggressive model
• Model aggressive in very distinctive way E.g striking on head with hammer & kicking around room saying words such as "POW"
• Children fustrated by being shown toys they couldn't play with.
• Taken to room where among other toys was bobo doll
• Results
• Children who watched aggressive model reproduced much of verbal & physical behaviour
• Other group showed virtually no aggression towards doll
• Aprox 1/3 of children in aggressive condition repeated verbal responses. None of other group made such remarks
• Boys more aggressive than girls in behaviour but not words

• Divided 66 nursery children into 3 groups 
• All 3 groups watched film where adult kicked & punched bobo doll
• Three conditions: 
• Condition 1: adult rewarded
• Condition 2: Adult told off
• Condition 3: Neither rewarded or punished
• Findings
• Condition 1: Children behaved most aggressive
• Condition 2: Children behave least aggressive
• Children learnt through vicarious learning. All children learnt how to be aggressive condition 2 performed just as many aggressive when offered rewards to do so. 

• Other support- Patterson et al 1989 aggressive children raised in aggressive homes
• Reliability- carries out in lab IV & DV controlled 
• Individual differences- Can explain differences in aggression
• Can explain differences in society- !Kung San of Kalahari Desert 

• Methodology- In lab lacks ecological validity, demand characteristics, doll designed to be hit, can't be applies to real life situations
• Does it apply to adults?- Only involve children Philips murder rates increase in US after major boxing match
• Reductionist- doesn't look at biological factors
• Ethical-No protection from harm, children encouraged to be aggressive

• Individual transformed when part of crowd, loose self control, capable of acting in way goes against personal norms
• Occurs when person no longer identified as individual (In crowds,wearing uniform or disguise) 
• Affected by drugs & Alcohol
• Behave in ways they would not as individuals
• Research suggests people more violent in groups
• Reduced sense of guilt & less concern about being judged by others
• based on primitive urges less fear of punishment
• 'Baiting crowd' urge person attempting suicide jump

• Zimbardo 1969: four female students asked to give electric shocks. Half bulky lab coats, hoods, Separate cubical, dimly lit cubical, never referred to by name. Others normal clothes, brightly lit room, big name tags, introduced by name. individuation condition shocked for twice as long. 
• Malamuth & Check 1981: Male students American Uni found 1/3 might commit rape if no chance of being identified
• Mann 1981: Analysed suicide leaps in America.10/21 cases where crowd gathered baiting occurred, usually at night, large crowd, some distance from person.
• Watson et al 1973: Looked at how 23 societies changed appearance before war. Those who changed appearance more likely to kill, maim & torture victims
• Rehm et al 1987: Wearing uniform parts of sport team increased aggression. Children handball one team wore orange vests others normal clothes. Orange shirts played more aggressively.

• Prosocial behaviour/lack of support: doesn't always lead to aggression disasters show large groups act in selfless way.
• Depends on Social norms: being in group could conform to group norms that could be prosocial.
• Not always uncontrolled: Looting in American Riots controlled with selected targets. Football fans have certain rules for aggression.
• Gender differences: Male & female groups may respond different.
• Methodology/gender bias: Zimbardo only females. costumes similar to Ku Klux Klan (demand characteristic). Watson cross cultural studies could be biased.

• Irwin & Cressey 1962 
• Prisoners bring into prison own histories and traits & this influences prison environment 
• Younger inmates more difficulty adjusting & be more violent than older inmates.

Harer et al: data from 58 prisons, black inmates higher rates of violence, lower rates of alcohol & drug use. If prison itself you'd expect no difference

• Prison or hospital itself that cause violence rather than people in it. 
• Conditions included crowding, loss of freedom, loss of sex, boredom & loneliness. Lead to extreme stress & frustration. 
• Trainee nurses more likely to suffer violence  

• Stanford prison experiment Zimbardo et al 1973:
• randomly allocated roles of prisoner & guard asked to act out life in prison.
• Guards became too vicious towards prisoners
• Before study no difference between groups so must've been situation
• McCorkle et al 1995:
• lack of privacy, overcrowding & lack of meaningful activity significantly increased prison violence
• Research not consistent. Psychiatric institutes found increasing space didn't decrease violence.
• Deterministic if prison to blame prisoners can't be blamed for actions
• Practical applications poor Environment known to cause aggression authorities have moral duty to change them.
• Ethical problems Zimbardo didn't protect ppts.

• special rituals for new members of group
• create bond with new members & show physical & mental toughness
• Particularly common in military 
• 2006 on russian solider had to have legs & genitalia amputated after being brutally beaten
• Another lost leg after being forced to sit on block of ice for 4 hours.
•  

• In prisons research found domination of weak essential  to maintain status.
• Problems arise deciding whether it has or has not happened 
• Many people involved regard it as fun
• student 1/5 reported what researchers defined as hazing yet 1/20 regarded themselves as experienced it.

• Highlights importance of prison & prisoner
• Suggests first prisoner to act aggressively is first piece of popcorn which explodes in saucepan.
• After heat is applied other prisoners will explode & act aggressively

• Examples:
• Murder of 6 million Jews by Nazi's in WW11
• Murder of 800,000 Tutsi & moderate Hutu by Hutu extremists in Rwanda in 1994

• Dehumanisation: target group dehumanised made to seem worthless animals
• Obedience to Authority: Milgram believed holocaust result of situational factors forced Nazi soldiers to obey leaders whatever own morals.

• Serotonin
• Thought to reduce aggression by inhibiting emotions that could lead to aggressive response
• Low levels associated with impulsive behaviour, aggression & violent suicide.
• Studies of pets breed to reduce aggression have high levels.
• Mann et al gave 35 health ppts drug known to reduce serotonin. Using questionnaire to assess hostility found in MALES increase in hostility & aggression
• Dopamine

• high levels of dopamine associated with high levels of aggression 
• when dopamine has been increases using anphetimines increase in aggression found
• Antipsychotics that reduce dopamine have shown to reduce aggression

• Alcohol & Serotonin: alcohol causes major disturbance in metabolism of brain serotonin.
• Evidence from non humans: vervet monkeys those fed diet high in serotonin showed low levels of aggression. position not quite so clear in humans than animals
• Alternative explanations: possible not caused but low levels of serotonin but low serotonin metabolism
• Hard to show how dopamine works: studies with mice show when dopamine is turned off they find it difficult to move so lack of aggression could be due to this.
• Result not cause?: Dopamine could be result not cause of aggression
• Reductionist/Deterministic

• Testosterone
• Male sex hormone 
• thought to influence aggression from early teens
• Dabbs et al measured testosterone in saliva of violent & non violent criminals those with highest levels had history of violent crime.
• Young males who behave aggressively when drunk have high testosterone levels 
• Cortisol
• High levels decrease effect of other hormones such as testosterone 
• increases anxiety so causes social withdrawal
• high levels inhibit testosterone so inhibit aggression
• studies shown low levels in violent offenders & school children

• Support: meta analysis found weak but positive correlation between testosterone & aggression
• Inconsistent: other studies no relationship
• Methodology: Correlations no cause & effect. small samples of men from prisons, Self report measures inaccurate or judge aggression solely on crime committed 
• Only males: Most studies with testosterone & aggression involve males only. Link between testosterone & aggression even higher in women
• Aggression or dominance?: people aggressive if want to inflict injury but dominant if want to achieve/maintain status
• Reductionist/Deterministic

• Coccaro et al 1997 looked at adult twins found 50% concordance rate of aggression towards others. 
• Meta analysis confirmed strong genetic basis for aggression

• Twins brought up in same environment & treated similarly difficult to isolate genes & environment.
• Hutchings et al 1975 14,000 adoptions in Denmark  significant number of adopted boys with criminal convictions had biological parents with criminal convictions.

• gene responsible for producing protein MAOA associated with aggressive behaviour 
• Controls serotonin production in brain, low levels associated with impulsive, aggressive behaviour

• Family in Netherlands many men history of extreme violence
• Analysed chromosome of 28 family members found genetic defect on X chromosome.
• Abnormally low levels of MAOA in bodies

• 5000 male children found link between MAOA & aggression .
• Those with low levels more likely to commit anti social behaviour if mistreated as children as well.
• Those with high levels that'd been mistreated & those with low levels who hadn't didn't show anti social behaviour. 
• Interaction between genes & environment important 

• Gene-enironment interaction: inherited temperament or personality characteristic puts some people more at risk of committing violent crime. nature & nurture. Brennan 1993 found genetic influences significant in property but not violent crime
• Methodology 
• Problems with twin studies: brought up in same way involve small samples
• Problems of measuring aggression: Self report or observation. difficult to compare thoseusing  observation found less genetic influence
• Problems in sampling: convictions for violent crimes rare people convicted not necessarily persistent violent offender could be one off. 
• Free Will
• Reductionist

• good hunters and skilled fighters able to get rid of rival males and gain more resources
• Given them high status made them attractive to females
• ensures survival of the fittest 
• could've been costly for males not to engage in fights
• low status men at risk of not producing off spring

• Face validity: survival of fittest makes sense
• Yanomamo tribe of amazon: one most common cause of aggression is access to women. More successful warriors more wives & children
• World War 11: Germans invading Eastern Europe carried out systematic rape & women in concentration camps often abused
• Murders: Daly Wilson Looked at fights ending in murder. Low status males engage in more risky strategies to gain status & look more attractive to females. 
• Triads & Gangs: Leader almost always most dominant & Aggressive. 

• women always 100% certain child she gives birth to has her genes
• Males never 100% sure evolved behaviours to reduce risk
• Male aggression against females designed to deter female from sleeping with other males.
• Direct guarding of females 
• Threats
• Uxorocide- wife killing may be unintended outcome of behaviour meant to control rather than lead to death

• Murders in Married couples: 80 murders 44 husbands 36 wives although more husbands evidence shows done in self defence. nearly 1/3 from sexual jealousy.
• Evidence from victims themselves: 44 battered wives women's hostil in Canada 55% cited jealousy as reason for beatings.
• Can help prevent violence: Practical application male retention tactics early sign of violence. Alert friends & family.
• Shackleford et al & Uxorocide: 14,000 murders where man killed wife. Young women more at risk regardless of mans age. suprising most vunrable in terms of fertility. disagrees outcome is accidental. Infedility carries double loss, loss of partner & anothe man gains partner by killing wife eliminates competitor gaining reproductive stakes

• Generally viewed less aggressive 
• Aggression High risk strategy 
• Males risk outweighed by possible gains
• Females costs outweigh benefits
• Mothers presence more crucial for child than fathers 
• If women wants children to survive must be more concerned for own survival 
• High status & aggression not seen as attractive to men aggression not adaptive
• LEd to development of low risk indirect strategies such as gossiping & name calling. aimed at reducing attractiveness of competing female. 

• Males 4 times more likely to use physical aggression than females
• Students asked how they'd respond in aggressive situation majority of men said direct physical aggression most women said walk away.
• Research not consistent. Some research shows in family conflict women start & cary out physical acs as often as men goes against theory.

• Cultural Difference: can't explain differences.  !Kung Tribe
• Individual differences: Can't explain why individuals act in different ways. If 3 men faced with wife's infidelity one result in beating one in murder other in getting drunk
• Post Hoc: After the fact. explains behaviour after it's happened doesn't make prediction & test it. 
• Deterministic
• Reductionist
• Ethical Implications: Creates diversion between men & women. back up sexual stereotype men more aggressive than women. Give justification for aggression & rape.

• Like war no deaths
• Benefits to players
• Shows off Skills
• Intimidation
• Football hooliganism (gain status fro working class males & Fear of strangers (Xenophobia))

• Seems contradictory
• Helps Protect 
• Examples

• Shows commitment
• Stops others free loading

• Difficult to prove
• Free will
• Reductionist
• Simplistic

• Mood
• Health concerns 
• Culture
• Role of learning

• One explanation for eating particularly junk food is to escape low mood
• People who are stressed or depressed tend to increase carbs & fat content of meals
• Wegner et al 2000
• Students recorded eating patterns & sleep over 2 weeks. Binge days linked with low mood. no difference in mood before & after binge. Low mood may make binge more likely but doesn't relieve low mood.
• Garg et al
• food choice of 38ppts watching either happy or sad film. offered buttered popcorn & seedless grapes throughout. Those watching sad film ate 36% more popcorn. happy film group ate far more grapes
• Serotonin hypothesis
• carbs contain amino acid tryptophan essential for brain to make serotonin. Serotonin associated with improved mood. However small amount of protein as in chocolate stop tryptophan entering brain so unlikely explanation.
• Opiate Hypothesis
• Opiate neurotransmitters act like heroin, produce feelings of pleasure & reward. sweet foods increase endorphins & activate natural reward pathway.
• Individual difference hypothesis
• Differences in how we respond to stress. external eaters eat tempting food if hungry or not. Internal eaters respond to internal cues for hunger.

• West obesity, heart disease & diabetes growing.
• Success of health diet depends on knowledge money & time available.
• Slow process of Jamie Oliver campaign shows how hard it is to change established attitudes to food.
• survey schoolchildren 82% believed healthy living personally important doesn't correlate that 20% are obese. gap between attitude & behaviour
• Orthorexia-eating disorder people eat highly restricted diet try & avoid anything unhealthy. Can include pesticides, artificial additives or anything genetically modified. extreme cases malnutrition & death.

• Availability 
• Tend to eat food available in region. Mediteranian people lower levels of heart disease & obesity thought to stem from diet high in olive oil, low dairy produce & high levels of fruit & veg.
• Religion & Festivals 
• Most religions forbid eating of certain food or certain items prepared certain ways. Fasting.CUltures attach meaning to certain food. eating major part of celebrations.
• Globalisation 
• Cultural diversity being reduced by globlisation of food. Fast fod available world wide.Pica Indians those who stay in community low levels of obesity those who move to American Culture high levels. Lesham looked at bedouins in urban environment compared to desert bedouins & jewish women. little difference in diet of desert & urban bedouins (high salt intake) both groups very different diet to jewish women. High salt intake related to living in desert. Cultural explanation reductionist as some evolutionary involvement carried on when in urban environment. Also looked at christian & muslim groups living in Isreal. Muslim community carb intake twice that of Christian as well as higher levels of protein, fat & salt. BMI index virtually identical. Cultural differences important even when access to same food.

• Parents
• Provide food for child so their attiude will affect child's. strong cerrelation between diets of mothers & children. Association between parents & childrens attitudes to food generally. Correlations found betwen parents & children in terms of snack intake & body dissatisfaction. Common technique reward children with food they like for eating food they don't. Works short term but long term increases liking of reward food & decreases liking of diliked food.
• Peers
• Modelling using peers who are admired can increase fruit & veg intake. Meyer & Gast looked at 10-12 yr old girls found significant poitive correlation between peers & poor eating habits. Likeability of peers considered most important factor.
• Media
• Children exposed to food advertisments on telly use animation peer models to make food look attractive. Can affect prefernces unfortunatley foods tend to be unhealthy can contribute to childhood obesity.

• Gender bias: Most studies done on women males may respond in different ways. Men homosexuality is risk factor.
• Reductionist
• Deterministic
• Different samples: ppts come from different groups so can't generalise particularly when looking at culture.

• Restraint Theory
• Role of denial
• Attention to detail

• People try & restrict food intake. Hermann & Mack say often increases likelyhood of overeating.
• Preload Test
• ppts given food preload either high or low in calories then given taste test. They dont know amount of food they eat is being measured. After calorie rich preload restraint eaters should feel full & eat less. Many studies found opposite.
• Boundary Model
• Restrained eater have coginitve boundary once pasted 'what the hell effect'.

• Implications for treating obesity
• Limited relevance 
• Cultural differences in obesity
• Methodological issues reliable but lacks ecological validity

• People try and loose weight by not thinking/eating about certain foods. Research shows this has opposite effect.
• Wegner et al 1987 asked ppts not to think of white bear. results showed those told not tot think about the bear thought about the bear more often than those told to think about the bear.
• Wegner admits ironic effects not huge but such effects could be signs of more serious forms of eating behaviour.

• Claims people usually like things less if they repeat them. Makes sticking to diet regime hard. Riddin suggests we should not think "not another salad" but focus on detail of meal therefore get less bored.
• Jelly bean experiment 135 pp 22 jelly beans each one group saw bean detail other group saw flavour detail. pp that saw more general info got bored faster.

• Anecdotal evidence:
• may not be 100% accurate
• Success & failure of diet not objective less reliable 
• Free will & deterministic: some factors could be genetic.

• Attention to detail
• Lifestyle changes: Physical exercise, Group & individual support, Self Monitoring, Set realistic goals
• Pharmacological & Surgical Techniques: Drugs: Orlistat & Sibutramine & Surgery: Gastric band & Gastric bypass

• Humans homeostatic animals try and keep constant internal environment
• Apart from pregnancy or growing, humans keep same body weight within narrow limits (set point theory)

• Triggered by liver when glucose levels are low in blood
• Initiates food-seeking
• Paraventricular hypothalamus responsible for telling person specific food they need - linked to cravings

• Damage to LH in rats led to aphagia (absence of eating)
• Theory caused some problems, damage to LH causes problems in other areas eg thirst and sex
• Other research shows eating controlled by other neural circuits in the brain

• Main area involved in satiation
• Initiated when glucose levels rise or when hormone CCK is released

• Damage to VHM in rats caused them to overeat
• Gould found lesions in VMH alone didn't cause overeating, his research has not been replicated

• Although blood glucose levels do respond rapidly to food intake, problems with the theory that glucose levels signal to the brain to tell us to stop eating
• Don't vary much under normal circumstances, not enough to be effective signal to brain
• People with diabetes, long-term high levels of glucose but normal apetites

• Help us choose food on basis of previous experience
• Surgically removing amygdala in rats caused them to eat both familiar and new foods
• Normal rats would initially avoid new foods
• If healthy adults exposed to unpleasant smells, blood flow to amygdala significantly increases

• Empty stomach sends messages to the brain via neural pathways to eat
• Cannon persuaded Washburn in 1912 to swallow deflated balloon, measured stomach contractions in relation to W's hunger, found W's hunger pangs were correlated to stomach contractions - supports
• However, people who have lost some or all of stomach still able to regulate food intake - other mechanisms involved

• The way stomach sends signal via neural pathway to brain is through hormone ghrelin
• Hormone secreted in stomach, amount released directly linked to emptiness of stomach
• Gastric bands reduce ghrelin production from stomach

Cummings et al 2004 - 6 participants, allowed to eat lunch, ghrelin levels monitored every 5 mins, fell immediately after eating lunch, lowest level after 70 mins, slowly began to rise, peaked as participants asked for evening meals, 5 out of 6 participants closely correlated with degree of hunger reported

• Well controlled study, changes due to hunger rather than external queues
• Participants all male and small sample
• Ethical issues but approval gained from ethical committee and participants, gave full consent and fully debriefed afterwards

• Sends messages to brain to reduce eating
• Injections of CCK in animals reduce meal size
• Animals with genetic mutation eliminating CCK become obese

• Understanding biological systems important when explaining human eating behaviour
• Reductionist
• Studies with animals - can't generalise
• Practical applications

• Early diets
• Poison avoidance
• Morning sickness

• Sweet foods encourage people to eat fruit with natural fructose content
• Provide important calories
• Desor suggests even 1-3 day old infants prefer sweet flavours - shows innate
• Natural avoidance of bitter foods help to protect people eating poisonous food, neophobia - fear of eating novel foods
• Preference for salt less easy to explain
• Preference for meat - without meat wouldn't have been able to grow brains, so adapt to environment and survive today
• Far more efficient means of obtaining protein than plants and leaves, and will have increased reproductive fitness of lower-ranking males, could exchange with females for sex

• Showed importance of calories in ancestral diet
• Asked 4-5 year old children which fruit and veg they preferred, found choice not dependent on sweetness or familiarity or how much protein they contained but in how dense they were in calories

• Cooking kills bacteria; spices, onion & garlic extremely effective at killing bacteria
• Taste receptors: bitter and sour, help us identify gone-off food
• Food neophobia - fear of the new
• Taste aversion learning - Garcia et al: made wolves sick with lambs meat, when allowed to approach live sheep wolves would sniff then leave, learned to associate poison with sheep

• Happens for at least 75% of women
• Embryo protecting hypothesis
• Buss (2008) - said many foods shouldn't be eaten by pregnant women, baby most vulnerable in early weeks when major organs developing, this is when morning sickness is worst as it protects baby, sickness helps mother avoid foods which may be harmful

• Face validity
• Liking and disliking of foods is universal
• Fossil evidence
• Post hoc and lack scientific evidence
• Can't always explain modern food tastes
• Reductionist
• Deterministic
• Nature not nurture

• Body weight less than 85% than is normal for height and age
• Distorted body perception
• Intense fear of becoming fat
• Loss of 3 consecutive menstrual cycles (women)

• Hilda Brook (1973): individuals try and regain control over their life due to struggling with independence as parents wouldn't give it them
• Not wanting sexual maturity, caused in females who have unconscious desire to remain young, stops them from developing body shape associated with adulthood, results in boyish figure and no periods, keep illusion of being a child
• Family influences
• Minuchin et al: an enmeshment, parents interfering and over involved, no-one has clear identity as everything is done together, conflict avoidance - avoided or remains unsolved, by refusing to eat and making a stand for independence one area they can control
• Brook (1991): AN starts in early childhood with ineffective parents that don't respond sensitively to child's needs, make wrong decisions about whether or not they are hungry, means child has to rely on other people to tell them when they are hungry

• Brook's theory supported by observations of parents and teenagers with anorexia, tend to suggest what children's physical needs are rather than letting them say themselves
• All theories difficult to test, little support for most
• Based on view, anorexia only develops in teenage females
• Can't explain rise in disorder in last 50 years
• Parental conflict may be result of AN rather than cause

• Operant conditioning - behaviour repeated because it's rewarded. families praise persons thinness & self control. May be way of gaining acceptance from high achieving parents.
• Social Learning Theory - imitation of models, Western society - media portray attractive and healthy females as thin, in some girls means difference between real and ideal self, causes dissatisfaction with own body weight and shape which can lead to eating disorder
• Hoek et al: black females of Caribbean island much lower rate of anorexia, concluded because of media in Western lifestyle, black population still valued larger female body sizes
• Becker et al: looked at attitudes to eating on island of Fiji following introduction of TV, number of girls with eating disorders rose

• Can explain gender differences
• Can explain culture differences
• Can't explain why all women in one culture don't suffer
• Not all studies have found a difference between black and white groups
• Emphasis on Western culture

• Inaccurate judgment, obsessive thoughts, low self-esteem
• People have incorrect beliefs about their weight problem and body image
• Believe eating a small snack has noticeable effect on body size
• Slade and Russell: found anorexics overestimated body width by 25-55% but could judge other object accurately

• Face validity
• Successful in developing cognitive behavioural therapies
• Distorted thinking, could be effect rather than cause
• Doesn't explain where distorted thought comes from in the first place and why some have them but others don't
• Reductionist
• Led to useful therapies

• Gender bias
• Reductionist
• Ethical issues - internet communications used for qualitative data, no informed consent, protection or privacy

• Relatives of females with anorexia are up to 5-10 times more likely to develop it
• Family share similar environments so may not just be effect of genes
• Holland et al: looked at concordance rates for anorexia in MZ and DZ twins, found 56% concordance rate in MZ twins and 7% in DZ
• Concordance rate not 100% - suggests other factors
• Sample small so results unreliable
• Virtually all studies done in the West
• Although we knows genes are important we don't know what's inherited

• Serotonin - fewer receptors in brains of people with anorexia, changes still found in people who have recovered, which shows it is not just due to loss of body weight
• Dopamine - overactivity in dopamine receptors in anorexic sufferers
• Serotonin shown to affect personality traits associated with anorexia such as perfectionism, being obsessive and anxiety
• Problem with serotonin as cause that drugs which increase amount of serotonin not effective in treating anorexic patients - but can prevent relapse
• Chemical changes may be result rather than cause - starvation experiments with healthy volunteers produce changes in neurotransmitters similar to those with eating disorders
• Can explain why anorexia starts off in adolescence as this is time of hormonal and biological change

• Adapted to flee famine hypotheses
• Reproduction suppression hypotheses

• Guisinger (2003): anorexia evolved from behaviours that would have helped our ancestors survive in the environment of evolutionary adaptation
• May have been times when food supplies very short and behaviour such as cutting down on food, hyperactivity and denial of starvation would have been useful in local famine conditions
• Normally when a person faces starvation there is an increase in desire for food, depression and inactivity, useful to turn these behaviours off so people could increase chance of survival and have energy to move to more favourable environment

• Surbey (1987): In some species, females subjected to stress or in poor physical condition don't reproduce or have puberty delayed
• Helps survival as female wouldn't bive birth in conditions detrimental to survival of offspring
• Characteristic of anorexia that menstruation stops so it may have evolved when females feel unable to cope with biological or emotional responsibilities of womanhood

• No direct evidence of this as impossible to test scientifically
• Doesn't explain why anorexia is found mainly in women when both men and women would have been affected by hunger
• Difficult to see how it may have been passed on genetically when anorexia stops menstruation which would decrease fertility and maybe kill a person

• Treatment implications - biological treatments offer the promise of a range of treatment possibilities including gene-replacement therapy, but if AN due to family problems more difficult to change through treatment
• Gender bias
• Free will and determinism
• Reductionist