BIOLOGICAL RHYTHMS
Circadian Rhythms
The sleep-wake cycle
Core Body Temperature
Hormone
Evaluation
P: A study supporting the internal circadian rhythm, as a free-running rhythm is Michel Siffre’s Cave study.
E: Siffre (1972) spent 205 days in a midnight cave in Texas. He could illuminate his surroundings the way that he wanted; however, he had no way of knowing the time in the outside world. Researches found that at first Siffre's sleep pattern was erratic but it soon settled into a free running rhythm. They also found his day shifted to 25 hours in length.
C: Shows circadian rhythm exists in the absent of external cues
S: This study has low validity, as it is a case study, it cannot be generalised because individual differences may have affected the study.
P: Further support comes from Aschoff et al. (1976)
E: Had participants spend up to a month living in specially designed bunkers, which were built to shield participants from any external cues. It was noted that the participants kept a regular cycle of activity but after a few weeks’ participants were found to be half a day out of synch with the rest of the world. They found that the participants sleep wake cycle is maintained but it became free running.
C: This further supports the idea that the cycle operates without any external cues.
P: Support for the importance of external cues comes from Folkard et al. (1985)
E: 12 participants lived in ‘temporal isolation’ for 3 weeks isolated from natural light and other time cues. They agreed to go to bed at 11.45pm and get up when it said 7.45am. The clock initially ran to time but gradually quickened until it indicated a passing of 24hrs for 22hrs. All but 1 of the participants kept pace with the clock.
C: Suggests that the circadian rhythm can only be guided to a limited extent by external cues.
S: However, this study is a small sample size and therefore cannot be generalised to the wider population.
IDA
However, this theory is reductionist. It over simplifies the complex nature of rhythms down to genetic level. It is also deterministic as it suggests that rhythms are fixed by internal mechanisms.
Infradian & Ultradian Rhythms
ULTRADIAN
Sleep Stages
Basic rest-activity cycle
INFRADIAN
Monthly cycles
Seasonal Affective Disorder
Evaluation
P: A strength comes from Dement and Kleitman (1957)
E: They demonstrated the link with REM and dreaming. Participants were likely to report dreaming during REM. This could potentially provide way to identify dreaming, to help explain it.
C: This strengthens the theory that REM is characterized with dreaming.
P: A strength of the basic rest-activity cycle is put forward as its shown to be there and important
E: This was found that the importance of this 90-minute rhythm Is a form of timing to ensure that biological processes work in unison.
C: This is a strength because it suggests that the 90-minute cycle is important.
P: A strength of the infradian rhythm is put forward by Russell et al.
E: In this study, a group of women has their sweat samples taken. It was then rubbed on the top lip of another group. They found that their menstrual cycles became in sync.
C: This is a strength because it’s shown that the synchronisation of the menstrual cycle is governed by pheromones.
IDA
This approach is very determinist as it removes the free will of the individual, assuming they will behave in a certain way, which ignores all other social factors that may be an issue.
Endogenous Pacemakers & Exogenous Zeitgebers
ENDOGENOUS PACEMAKERS
The Suprachiasmatic Nucleus
Basic rest-activity cycle
EXOGENOUS PACEMAKERS
Light
Social Cues
Temperature
Evaluation
P: Evidence to support the role of the SCN comes from Morgan 1995
E: He bred ‘mutant’ hamsters so their circadian rhythms was 20 hours, instead of 24 hours, then transplanted their SCN into a normal hamster. Those hamsters then displayed the mutant rhythms.
C: This shows how the SCN is the dominant endogenous pacemaker that is not affected by exogenous factors.
S: However, as this study was done on animals, it cannot be generalized to humans, as we are far more complex biologically.
P: However, there is evidence to go against the SCN as the main endogenous pacemaker.
E: Kate Aldcroft spent time in a cave, after 25 days her temperature was a 24-hour rhythm, yet her sleep rhythm was in a 30-hour-cycle.
C: Suggesting that the SCN is not in charge and doesn’t control all rhythms, and that something external may have affected the rhythms.
P: A study to support Light as a dominant zietgeber comes from Campbell and Murphy
E: They shifted circadian rhythms just by shining a light on the back of someone’s knees.
C: Thus suggesting that artificial lighting does have effect on entraining rhythms.
S: Further support comes from Boivin et al 1996 who found that circadian rhythms can be entrained by ordinary dim lighting, although bright light is more effective.
P: Stevens 2006 suggested that artificial light might have some negative consequences.
E: He stated that exposure to artificial lighting disrupts melatonin production, so women in industrialized areas are more likely to develop breast cancer.
C: Further suggesting that light affects our circadian rhythms.
P: Research to support the idea that social cues entraining rhythms comes from Fuller et al; 2008.
E: He found that adhering to social cues ceases symptoms of Jet Lag, possibly because some of our body clocks are reset by food intake.
C: Suggesting that social cues also play a part in entraining our rhythms.
IDA
However, most of the data collected derived from experiments with animal. Thus we are unable to fully generalize the findings to humans. Also, the biological approach is too deterministic, as it doesn’t take into account individual differences.
Consequences of Disrupting Biological Rhythms
Shift Work
Jet Lag
Evaluation
P: A weakness of shift work is that there are other factors involved.
E: Shift work effects are not just due to the disruption of biological rhythms. They may be due to the lack of sleep associated with going to bed at odd hours. Experience social disruption, as they cannot spend time with family and friends. Divorce = as high as 60%.
C: Suggesting that there are other consequences to disrupting biological rhythms than shift work.
P: Another weakness of jetlag and shiftwork comes from Bovin et al.
E: Who looed at the power of lighting in resetting biological clocks. Used 31 males in 4 groups, who were ‘exposed’ to different conditions. Each group had advanced to a different degree, group one – 5 hours, group two – 3 hours, group three – 1 hour and group four – 1 hour LATER
C: Shows that even room lighting can have an effect on the circadian rhythm, not just jetlag or shift work
S: However, this experiment was conducted in a lab, thus having low mundane realism and may not be applicable to the real world.
S: Although, since the extraneous variables are controlled, they can be certain that the independent variable caused the dependent variable
P: Research evidence to support jetlag as a consequence from disrupting biological rhythms comes from Klein
E: He tested 8 participants flying between the USA and Germany. They found that adjustment to jet lag was easier for people of westbound flights than eastbound.
C: Suggests that the direction of the flight is and important factor in determining the effects of jet lag.
S: Further support comes from Schwartz who found that baseball sides from the east of the USA played better against teams in the west than western sides did playing against teams in the east. Supports phase advance.
P: A weakness of jet lag disrupting biological rhythms is that there are other factors involved.
E: Jetlag may also be affected by other factors, (other than disruption of biological rhythms). An individual may sleep badly the night before travel, because of worry/excitement. Travel itself is also tiring and many holidays include long trips to the airport before the flight. As well as alcohol, coffee and noise.
C: Suggesting that there are other factors that contribute to jetlag as well as disrupting biological rhythms.
P: A way of reducing the symptoms of jet lag is by taking melatonin.
E: Melatonin is a natural hormone that induces sleep. Herxheimer and Petrie 2001 reviewed 10 studies and found that when melatonin was taken near to a normal ‘bed time’, it was remarkably effective.
C: Thus it could be taken to induce sleep at a normal time in a new time zone.
IDA
However this is a biological approach and doesn’t take into account individual differences. Reignberg et al found that people who gave up shift work because they couldn’t cope tended to have rhythms that change a lot while on shift, whereas ‘happy shift workers’ had unchanging body rhythms.
The Nature of Sleep and Lifespan Changes
Infancy
Childhood
Adolescence
Adulthood and Old Age
Evaluation
P: Babies may sleep longer as an evolutionary adaptation to make their parents lives easier, and allow them to get on with things that increase their survival chances e.g. cooking. They also may wake in the night because they need feeding, and if they didn’t they would go cold and hungry.
E: Infants higher REM/Active sleep may be because a significant amount of learning is taking place, as REM is associated with consolidation of memories and production of neurotransmitters.
C: Supported by the fact the premature babies spend 90% of their sleep in REM.
P: Sleep changes may be linked to hormone production.
E: These hormones are primarily released at night therefore sleep patterns are disturbed, leading to deprivation. Many correlates of sleep deprivation are thought to be typical of puberty e.g. moodiness, poor attention span, and irritability.
C: Suggesting that hormonal changes can also explain the upset to the circadian clock, described as delayed sleep syndrome. Crowley et al 2007
S: Wolfson and Carskadon 2005 recommended schools begin their day later to accommodate for the poor attention spans of adolescents in the early morning.
P: Recent studies have found there to be a mortality risk associated with too much sleep.
E: Kripke et al 2002 surveyed over 1 million adult men and women and found those only sleeping 6 or 7 hours had a reduced mortality risk, whereas those sleeping an average of 8 hours had a 15% risk, with those sleeping 10 hours having a 30% increase.
C: This suggests … ( I am not quite sure how to end this :S)
S: However this is only correlational data and therefore may not know the cause and effect.
P: Reduced sleep can also be explained in terms of physical sleep problems e.g. apnoea or medical illnesses.
E: Van Cauter et al 2000 stated, the fact that SWS is reduced, older people are more easily woken. The reduction of SWS leads to ta reduction in HGH; so this could explain some problems in older people, e.g. bone density and lack of energy. Sleep deficit in old age may explain why they experience impaired functions e.g. decreased alertness. Taking melatonin and other techniques can treat this.
C: Suggesting .. (also don’t know how to end this..)
IDA
However this theory is culture bias. Tynjälä et al 1993 looked at sleep patterns in 400,000 11-16 yr. olds living in different cultures in 11 European countries. Found that an important factor was the number of evenings spent outside the house, meaning they went to bed late and had little sleep because they had to get up early.
Shin et al 2003 found that Korean meal adolescent sleep time was 6.5 hours and Ghanizadeh et al 2008 found a mean time of 7.7.
Functions of Sleep: Evolutionary Explanations
Energy Conservation
Predator Avoidance
Foraging Requirements
Waste Of Time
Unilateral Sleep
REM and NREM Sleep
The phylogenetic signal
Evaluation
P: Support for Predator avoidance comes from Allison and Cicchetti 1976
E: Who found that species who had a higher risk of predation did sleep less, although there were some exceptions e.g. rabbits who had a high danger rating, but slept as much as low rated moles.
C: Supporting the idea of predator avoidance when it comes to animals surviving.
P: However recent research by Capellini et al 2008 accused older research of not using standardised methods , and so carefully selected data to carry out a meta analysis.
E: They found a negative correlation between metabolic rate and sleep, which doesn’t support the theory.
C: Thus showing there to be more than just evolution behind the need and function of sleep.
P: Mukhametov 1987 supports unilateral sleep
E: He found that dolphins had to come up to the surface to breath, and so could not fall in deep sleep underwater or they would drown. So they adapted their sleep to unilateral, so the brain hemispheres would swap every two to three hours.
C: Thus supporting the idea that certain animals adapt to their surroundings in order for them to survive.
P: Support for Energy conservation comes from Zepelin and Rechtschaffen 1974
E: They compared sleep habits across species to investigate the costs and benefits. They found that smaller animals with higher metabolic rates sleep more than larger animals. C: This supports the view the energy conservation may be the main reason for sleep, although there are some exception e.g. the sloth, who sleep 20 hours a day, despite begin large.
P: Allison and Cicchetti 1976 support NREM and REM sleep
E: They found that larger animals had less NREM sleep, but not less REM sleep.
C: This shows that it is important for conservation.
* P: However Capellini et al found no correlation between body size and NREM sleep.
E: This is further supported by more primitive animals e.g. reptiles, who only have NREM sleep.
C: This suggests that NREM evolved first and was adapted as a way of conserving energy, whereas REM may have evolved later as a way of maintaining brain activity.
IDA
Horne 1988 put forward a theory that combines elements from restoration and evolutionary theory. He suggested a distinction between core and optional sleep. Core sleep is mainly SWS and vital for restoration of body and brain, whereas optional sleep in mainly REM and has the function of occupying unproductive hours and conserving energy.
Primary Insomnia
Secondary Insomnia
Teenage Insomnia
Primary VS Secondary Insomnia.
Consequences Of Insomnia
A Model to Explain Insomnia-
P: A study to support/weaken Insomnia comes from Ohayon and Roth 2003
E: They found that, in a study of almost 1500 Europeans, insomnia more commonly preceded than followed mood disorders.
C: This means that for some people, it may be helpful to treat the insomnia, whether it is a primary or secondary effect.
P: Insomnia could cause cognitive impairment e.g. poor concentration and memory loss.
E: Zammit et al 1999 found that patients with insomnia scored lower on the Medical Outcomes Study Cognitive Scale than the control patients, showing problems with memory, reasoning, problem solving and concentration.
C: Suggesting that insomnia may likely lead to harsh consequences.
P: Insomnia may also cause severe accidents. Sleepiness and cognitive issue make a risk for safe driving.
E: Arendt et al 2001compared the performance of adults deprived of a day of sleep with some given alcohol, and found that even keeping people awake for 3 more hours than usual lead to impairments equivalent to modest alcohol levels.
C: Thus showing how insomnia could have detrimental consequences to people’s lives.
P: Insomnia could also cause psychological disturbances.
E: Its possible that insomnia is actual the cause of some psychological problems e.g. depression, rather than the effect. Including drug and alcohol abuse (Breslau et al.)
C: Suggesting the insomnia could be the root of some psychological problems.
P: Insomnia also causes the Immune system to under function.
E: Savard et al 2003 found that in Canada, there were fewer immune cells in the people suffering chronic insomnia than in good sleepers.
C: Thus suggesting that insomniacs more prone to illnesses.
S: However there is an issue with cause and effect, as if stress is the cause, then stress affects the immune system as well.
P: Evidence to support predisposing factors comes from twin studies.
E: Watson et al 2006 who found that 50% of the variance in the risk for insomnia could be attributed to genetic factors.
C: Suggesting that insomnia could be the result of genetics.
S: Research also suggests that physiological factors may predispose people to develop insomnia.
IDA
One of the causes of primary insomnia is the person’s belief that they will have difficulty sleeping. A clever way to treat this is to by the attribution theory method, where the person who has learnt to attribute their sleeping difficulties to insomnia can be convinced the source is elsewhere, and so ends their dysfunctional attribution.
Explanations of Other Sleep Disorders
NARCOLEPSY
REM
HLA
HYPOCRETIN
Evaluation
P: REM is supported by Vogel 1960.
E: Who observed REM at the onset of sleep in a narcoleptic patient, compared to it normally occurring in the later stages of sleep.
C: Further supporting the explanation of REM.
S: Further support comes from Seigel 1999, who found that Cataplexy in dogs co-occurred with brain cell activity associated with REM. However, generally the research is unconvincing.
P: There has been evidence to weaken HLA as a common variant in narcoleptics.
E: The specific HLA variant is not found in all narcoleptics, and is reasonably common in the general public.
C: Suggesting it cannot be the sole cause.
P: Evidence for lower levels Hypocretic causes narcolepsy came from narcoleptic dogs.
E: Who had a mutation on chromosome 12, leading to a disruption of the processing of Hypocretin (Lin et al 1999).
C: Suggesting that low levels of Hypocretin cause narcolepsy.
S: These findings have been confirmed in human studies, where they found for example, lower levels of Hypocretin in their cerebrospinal fluid. (Nishino et al 2000).
P: However, there has been a lack of evidence to support narcolepsy as being inherited.
E: Hypocretin loss in humans is rarely due to only 1 gene and does not appear to be inherited due to lack of conclusive twin evidence. More likely that it is caused by brain injury, illness, diet, stress and possibly autoimmune attacks.
C: Weakening the theory that Hypocretin is inherited and causes narcolepsy.
P: Linking Hypocretin to HLA
E: Autoimmune attack links to involvement of HLA as mutations of HLA affect the immune response and so make the attacks more likely, maybe resulting in reduced number of Hypocretin cells. (Mignot 2001)
C: Suggesting that HLA and Hypocretin play a part together in causing narcolepsy.
IDA
Real world applications - Researchers are trying to create an artificial drug to replace the missing Hypocretin in the brains of narcoleptics. This is not a cure, but a way of controlling narcolepsy. Possibly in the future there may be a way of transplanting Hypocretin cells into narcoleptics brains.
Aggression
Social Learning Theory (SLT)
Social Learning Theory
Observation
Mental Representation
Production Of Behaviour
Bobo Doll Study
Evaluation
P: Phillips (1986) supports SLT
E: Daily homicide rates in the US increase in the week following a boxing match. Viewers imitated behaviours seen.
C: Social learning theory is evident in adults as well as children.
S: Does not take into account other extraneous variables.
P: Another support is that it can explain aggressive behaviour in absence of reinforcement.
E: Although participants behaved aggressively after observing models, at no point were they rewarded.
C: Shows vicarious learning is necessary – children learn about consequences.
S: Does not account for individual differences.
P: More support comes from Wolfgang and Ferracuti (1967) – can explain differences.
E: Propose in large societies, some subcultures develop norms that sanction violence to a greater degree than dominant culture.
C: Shows people respond differently to different situations.
P: However, SLT can be used to explain cultural differences in aggression.
E: Among !Kung San or the Kalahari Desert aggression is rare. Answer lies in child rearing practices. When children argue, parent neither reward or punish them, separate them.
C: Shows cultural differences.
IDA
Deindividuation
Nature Of Deindividuation
Process Of Deindividuation
Research On Deindividuation
Reduced Self Awareness
Evaluation
P: Postmes and Spears (1998) weaken the theory.
E: Their meta-analysis of 60 studies found that antisocial behave is not more common in large groups.
C: Limited support for deindividuation,
P: Support comes from Robert Watson (1973)
E: Collected data on the extent to which warriors in 23 societies changed their appearance prior to going to war. Societies where they changed their appearance were more destructive to their victims.
C: Changing your appearance = more likely to act aggressively.
S: Recognises cultural differences.
P: Zimbardo (1969) supports the theory.
E: Group of 4 female undergrads required to deliver electric shocks. Half participants wore bulky coats and hoods and were not referred to by names. Other half was given name tags and could see each other.
C: Those in deindividuation condition gave shocks for twice as long.
S: Gender bias.
P: Spivey and Prentice-Dunn (1990) – increase pro-social behaviour as well.
E: Found deindividuation can lead to pro-social behaviour. When pro-social environmental cues were present participants performed altruistic acts.
C: Depending on the environment your deindividuation doesn’t need to lead to anti-social behaviour.
P: Mann (1981) supports the theory.
E: Analysed 21 suicide leaps in the US, 10/21 cases when a crowd watched, occurred at night.
C: It shows being part of a crowd caused deindividuation.
S: Cultural bias.
Institutional Aggression
Institutional Aggression Within Groups: Prisons
Interpersonal Factors
Gang Membership
Situational Factors – The ‘Deprivation Model’
The Pains Of Imprisonment – Sykes 1988
Institutional Aggression Within Groups: Genocide
Dehuminisation
Obedience to Authority
Evaluation
P: Harer and Steffensmier 2006 support the importation model in terms of individual factors.
E: They collected data from 58 US prisons. Black inmates = significantly higher rates of violent behaviour, lower rates of alcohol/ drug-related misconduct than white inmates. C: These patterns parallel racial differences in these behaviours, supporting the model.
P: Evidence to support claim that peer violence is used to relieve deprivation from institutions such as prison.
E: McCorkle et al. 1995 found that overcrowding, lack of privacy and the lack of meaningful activity all significantly influence peer violence.
C: Supporting the deprivation model.
S: However, research in psychiatric institutions is not consistent with this.
S: Ninja et al. 1999 found that increased personal space failed to decrease the level of violence among patients.
P: Bellisiset et al (2004) weakens gang membership theory.
E: Found inmates with gang involvement were not more likely to get involved than other inmates.
C: Suggesting that Gang membership doesn't pre-determine what happens in prisons.
S: Fisher 2001 – isolating known gang members reduced serious support. Weakens the research.
P: Stuabs model emphasises importance of bystander intervention in preventing genocide.
E: Doing nothing it appears, merely allows killing to continue. May escalate it by signaling consent.
C: However, bystander intervention does not necessarily end institutional aggression. Intervention can shorten conflict but may also hasten perpetrators to step up their genocidal policy within that period of time. (Rwandan genocide - 8,000 deaths per day).
P: Obrien 2003 claims that dehumanisation may explain violence against immigrants, seen by some as 'polluting threats to the social order'.
E: Esses et al. 2008 has demonstrated that individuals high in social dominance orientation have a tendency to dehumanise out-group members. (refuges, asylum seekers).
S: Supporting the theory that dehuminisation causes aggression within groups.
P: Mandel 1998 challenges Milgram's claim.
E: He argues that his account is mono-causal and does not match historical record.
C: Weakening Milgram’s theory of obedience to authority.
S: Goldhagen 1996 suggests that the main causal factor in Holocaust was a form of anti-Semitism.
Neural And Hormonal Mechanisms
Neural Mechanisms
Serotonin
Dopamine
Hormonal Mechanisms
Testosterone
Cortisol
Evaluation
P: Scerbo and Raine support for the importance of serotonin
E: A meta-analysis of studies found that lower levels of serotonin in individuals were described as being aggressive.
C: This supports the claims that serotonin depletion leads to impulsive behaviour, which leads into aggressive behaviour in various forms.
P: Evidence for the importance of serotonin comes from studies of animals that have been specially bred for domestication and for increasingly docile temperaments.
E: These animals have shown a corresponding increase, over generations, of levels of serotonin in the brain.
C: Supports the idea that high levels of serotonin block the stimuli that may lead to aggressive behaviour.
P: Evidence for dopamine as cause for aggression is inconclusive.
E: A study by Couppis and Kennedy rat study found that some individuals might seek out aggressive encounters because dopamine is increased as a positive reinforce in the brain when they engage in aggressive behaviours.
C: Suggesting that dopamine is more of a consequence of aggression rather than a cause
P: However, Scerbo and Rain challenges this theory.
E: A meta-analysis examined neurotransmitter levels in antisocial children and adults. They found lower levels of serotonin in individuals described as aggressive, but found no rise or fall of dopamine levels in this group compared to normal individuals.
C: Suggesting that dopamine has no effect on levels of aggression.
P: Albert et al. (1993) state that there is inconclusive evidence for the link between testosterone and aggression.
E: Some studies find no relationship between testosterone and aggression, most studies give small samples.
C: Not enough evidence to support testosterone.
P: Manzur (1985)
E: We should distinguish between aggression and dominance. Individuals act aggressively when they want to cause pain. Aggression is a form of dominant behaviour.
C: Aggressive behaviour may not be a reason of increase in testosterone.
Genetic Factors In Aggression
Twin Studies
Adoption Studies
Role Of MAOA
Genetics And Violent Crimes
Evaluation
P: Support comes from Miles and Carey (1997) – genetic basis.
E: Meta-analysis of 24 studies. Results = strong genetic influence, could count for 50% variance in aggression.
C: Shows genetics is a factor.
S: Ignores extraneous variables.
P: Further supports comes Rhee and Waldman (2002)
E: Meta-analysis, combines results of 51 studies, concluded aggression, anti social behaviour a product of genetics.
C: Shows genetics is a factor.
P: Plomin et al. (1981) weaken twin studies.
E: Twin pairs were encouraged to act aggressively to Bobo doll, by being exposed to an aggressive model. No difference in correlation.
C: Shows individual differences.
S: Ethical issues, protection from harm.
P: Walters (1992) argue against a gene in aggression.
E: Low correlation between hereditary and crime.
C: Data does not suggest there is a link between hereditary violence.
S: Extraneous variables not taken into account.
IDA
Evolutionary Explanations
Jealousy
Cuckoldry And Sexual Jealousy
Mate Retention And Violence
Sexual Jealousy And Extreme Violence
Infidelity
Sexual Coercion
Violence Toward Pregnant Partner
Uxorocide (Wife Killing)
Evaluation
P: Shakelford study particular tactics used by men are early indicator of violence.
E: Findings can be used to alert friends and family to danger signs, specific acts that lead to future violence in relationships.
C: Help sought or offered before violence happens
P: Takahashi supports male sexual jealous as a link to aggression.
E: neural response to imagined scenes of sexual infidelity and emotional infidelity different for men and women – men greater activation of amygdale and hypothalamus when sexual, women same but for emotional
C: Supporting the link between sexual jealousy and aggression.
P: Edlund and Sagarin argue that research is insufficient.
E: It doesn’t tell us whether locus of responsibility moderates the jealous response.
C: Suggesting that the research doesn’t say whether degree of perceived infidelity is important
P: Camilleri supports the link between infidelity and partner violence.
E: Risk of partner’s infidelity predicts sexual coercion among males, not females. Males risk of cuckoldry, not females.
C: Supporting the link that infidelity may lead to aggression.
S: Camilleri and Quinsey – men convicted of raping partners more likely to experience cuckoldry risks prior to offence compared to men convicted of non-sexual partner abuse
P: Further support of sexual jealousy comes from Burch and Gallup
E: Frequency of violent acts toward partners who were pregnant around double than those not pregnant, sexual jealousy characterising men who committed violence against pregnant partners.
C: Supporting the link between sexual jealousy and aggression in partners
S: Taillieu and Brownridge – women abused while pregnant more likely to be carrying child of a man other than partner.
IDA
Group Display As An Adaptive Response
Sports
Xenophobia
Territoriality
Warfare
Benefits Of Aggressive Display
Status
Costly Displays – Signals Of Commitment
Evaluation
P: Foldessi (1996) support the link between xenophobia and violent displays.
E: Hungarian football crowds - Racist conduct of extremist supporters led to increased spectators violence.
C: Supporting territorial displays.
S: Culture bias.
P: Lewis et al. (2005) support testosterone and territorial behaviour.
E: Among football fans, crowd support rated significant factors contributing to home advantage. Fans felt responsible for victory.
C: Supporting territorial behaviour.
S: Pollard and Pollard (2005) – displays of support hard to pinpoint.
P: Moore and Brylinsky (1993) – challenges home crowd advantage.
E: Measles Epidemic – 11 American basketball games for 2 teams played without spectators. Siena Saints NY nine games away, 5 with and 4 without spectators. Hartford Hawks Connecticut, 11 games, 4 without and 7 with. Siena Saints averaged 76:25 with and 86:70 without, Hartford Hawks 64:29 with 71:25 without.
C: Displays of support for home team crowds did not increase performance.
P: Warfare – Palmer and Tilley (1995) support sexual selection.
E: Male youth gang members had more sexual partners than normal young males.
C: These males were seen more attractive because of status.
S: Leunissen and Van Vught (2010) – military men greater sex appeal only if observed. Issue with criteria that actually watched them right.
IDA
Gender bias – Adams (1983), does not reflect women’s behaviour adequately. Idea of women warrior unheard of. Rare for them to fight, therefore the understanding is limited.
Success and failure of dieting
RESTRAINT THEORY – HERMAN & MACK (1975)
The Restraint theory `was an attempt to explain both the causes and consequences associated with the cognitive restriction of food intake. They suggested that attempting not to eat actually increases the probability of over-eating.
BOUNDARY MODEL – HERMAN & POLIVY (1984)
In an attempt to explain why dieting, might lead to overeating they created the boundary model. Model explains the failure of dieting in terms of the greater distance between hunger and satiety in dieters. It takes dieters longer to feel hungry and therefore more food to reach a state of satiety. In addition, dieters have a self-imposed desired intake. Unlike non-dieters, when they go over this threshold of desired intake, they experience a ‘what the hell’ effect, and continue to eat until they reach satiety, i.e. beyond the maximum level imposed as part of their diet.
RESEARCH SUPPORT – WARDLE & BEALES (1988)
Assigned 27 obese women to 1 of 3 groups for 7 weeks; restrained eating, exercise or non-treatment group. Women in restrained eating group ate more than women in other 2 groups.
LIMITED RELEVANCE – OGDEN argues that restraint theory may explain the overeating of some groups with disordered eating patterns (e.g. dieters, bulimics) HOWEVER the behaviour of restricting anorexics can’t be explained in this way. If trying not to eat results in overeating, claims Ogden, then how to restricting anorexics manage to starve themselves?
OBEISTY TREATMENTS BASED ON RESTRAINT MAY FAIL BECAUSE restraint theory suggests that restraint leads to overeating, yet the treatment of obesity typically recommends restraint as a way of losing weight. As a result, overeating may be a consequence of obesity treatment, leaving many obse individuals depressed, feeing a failure and unable to control their weight.
CULTURAL BIAS IN OBEISTY RESEARCH – IDA
Some cultural groups appear to find it harder to diet successfully because of a natural inclination to obesity. Asian adults are more prone to obesity than Europeans (PARK ET AL). Asian children and adolscents have a greater central fat mass compared to other ethnic groups (MISRA ET AL.)
FREE WILL OR DETERMINISM – BORN TO BE FAT? – IDA
It is likely that a number of genetic mechanisms exert an influence on weight, suggesting that the success/failure of dieting may be determined by factors other than an individual’s choice of lifestyle. One such gene codes for lipoprotein lipase (LPL), an enzyme produced by fat cells to help store calories as fat. LPL also makes it easier to regain lost weight.
THE ROLE OF DENIAL
Research in cognitive psychology has shown that attempting to suppress or deny a thought frequently has the opposite effect. WEGNER suggests any attempt to suppress thoughts of forbidden foods only increases the dieter’s preoccupation with the very foods they are trying to deny themselves. As soon as food is denied, therefore, it becomes more attractive.
THEORY OF IRONIC PROCESSES OF MENTAL CONTROL
Attempting to suppress a thought frequently has the opposite effect, making it even more prominent. Central to any dieting strategy is the decision not to eat certain foods. This results in a state of denial as dieters attempt to suppress thoughts about foods ‘forbidden’ as part of their diet.
RESEARCH SUPPORT - WEGNER ET AL.
Asked some participants NOT to think of a white bear, but to ring a bell if they did, and others to think about the bear. Results: those told NOT to think about the bear rang their bells far more often than PP’s who were asked to do so.
RESEARCH SUPPORT – SOTENS ET AL.
Found that participants who suppressed thoughts about food also showed a rebound effect, and were more likely to think about food after suppression. This might explain why denial of thoughts about food leads to greater than less preoccupation with it.
FREE WILL OR DETERMINISM – IDA
Some people find dieting ineffective because they have high levels of lipoprotein lipase, which makes body more effective at storing calories.
MAY BE GENDER DIFFERENCE IN LPL ACTIVITY
Research suggests that sex hormones play a part in LPL activity, e.g. oestrogen inhibits LPL activity, which explains why women put on weight after menopause when oestrogen levels are lower. A consequence of this is that dieting through restraint or denial may be more difficult for post-menopausal women for purely biological reasons.
REDDEN claims that people usually like experiences less when they have to repeat them constantly. When it comes to dieting, this makes it harder to stick to a particular regime. However, by focusing on the specific details of each meal, people get bored less easily and are better able to maintain their diet.
REAL WORLD APPLICATION – IDA
This has led to the development of anti-diet programmes aimed at replacing dieting with conventional eating. These emphasise regulations of eating by body hunger and satiety signals rather than the development if inappropriate attitudes to food (e.g. denial or restraint), which have been shown to be ineffective at weight control.
A meta-analysis of the effectiveness of anti-dieting programmes (HIDDINS & GRAY) found that they could improve both eating behaviour and psychological well-being, and led to weight stability rather than weight change.
The Environment of Evolutionary Adaptation
The Environment of Evolutionary Adaptation
PREFERENCE FOR MEAT - GOOD FOR BRAIN GROWTH
Taste aversion was first discovered by farmers trying to rid themselves of Rats. They found it was difficult to kill the rats by using poisoned baits because rats would only take a small amount of any new food, and if became ill would rapidly learn to avoid it. T.A was first demonstrated by GARCIA ET AL. Rats, made ill through radiation after eating saccharin developed an aversion to it because they formed an association between the illness and the taste of the saccharin.
ADAPTIVE ADVANTAGES
Taste aversion would have helped our distant ancestors to survive, because if they survive after ingestion poison than they could learn to avoid that food in the future. Once learned, taste aversions are difficult to shift, an adaption that would have helped survival.
THE ‘MEDICINE EFFECT’- the medicine effect describes a tendency for individuals to develop a preference for any food eaten just before recovery from an illness, which then becomes associated with feeling better
PREFERENCE FOR MEAT
Milton 2008 - Claims that without animals it is unlikely that we would have evolved into the intelligent creatures that we are today. This is because there simply would not be enough nutrition in a vegetarian diet.
TASTE AVERSION
TASTE AVERSION CAN BE EXPLAINED by biological preparedness. Differential learning abilities in different species has the ability to learn certain associations more easily than others; particularly associations that help them survive.
IDA – REAL WORLD APPLICATION - Research on the origins of taste aversion has been used to help understand the food avoidance that often occurs during chemotherapy in the treatment of cancer. This claim was supported in a study by BERNSTEIN & WEBSTER, who gave patients a novel-tasting ice cream prior to their chemotherapy and the patients subsequently developed an aversion to that ice cream. This has led to hospitals giving patients both a novel and a familiar food prior to their chemotherapy. Aversion then forms to the novel (i.e. unfamiliar) food and not to the familiar food. This is consistent with our evolved avoidance of novel foodstuffs (neophobia), which is consistent with our survival.
Circadian Rhythms
- Rhythms that last about 24 hours
The sleep-wake cycle
- In addition to external cues, there is also an endogenous ‘clock’
- The internal circadian rhythm is ‘free running' and works without any external cues
- There are external cues such as daylight
- These help adjust the internal clock to environment you live in
- These studies show that circadian rhythms persist despite isolation from natural light, demonstrates the existence of an endogenous ‘clock’
Core Body Temperature
- One of the best indicators of the circadian rhythm
- Lowest at 4:30am (36c)
- Highest at around 6:00pm (38c)
- There is a slight through just after lunch
- The temperature dip is a bi-daily rhythm
Hormone
- Hormone production also follows a circadian rhythm
- Cortisol is at its lowest around midnight and peaks around 6am
- Also produced when we are stressed
- Related to making us alert when we wake up
- Because cortisol levels are bit sufficiently high for alertness
- Also melatonin and growth hormone have circadian rhythm.
Evaluation
P: A study supporting the internal circadian rhythm, as a free-running rhythm is Michel Siffre’s Cave study.
E: Siffre (1972) spent 205 days in a midnight cave in Texas. He could illuminate his surroundings the way that he wanted; however, he had no way of knowing the time in the outside world. Researches found that at first Siffre's sleep pattern was erratic but it soon settled into a free running rhythm. They also found his day shifted to 25 hours in length.
C: Shows circadian rhythm exists in the absent of external cues
S: This study has low validity, as it is a case study, it cannot be generalised because individual differences may have affected the study.
P: Further support comes from Aschoff et al. (1976)
E: Had participants spend up to a month living in specially designed bunkers, which were built to shield participants from any external cues. It was noted that the participants kept a regular cycle of activity but after a few weeks’ participants were found to be half a day out of synch with the rest of the world. They found that the participants sleep wake cycle is maintained but it became free running.
C: This further supports the idea that the cycle operates without any external cues.
P: Support for the importance of external cues comes from Folkard et al. (1985)
E: 12 participants lived in ‘temporal isolation’ for 3 weeks isolated from natural light and other time cues. They agreed to go to bed at 11.45pm and get up when it said 7.45am. The clock initially ran to time but gradually quickened until it indicated a passing of 24hrs for 22hrs. All but 1 of the participants kept pace with the clock.
C: Suggests that the circadian rhythm can only be guided to a limited extent by external cues.
S: However, this study is a small sample size and therefore cannot be generalised to the wider population.
IDA
However, this theory is reductionist. It over simplifies the complex nature of rhythms down to genetic level. It is also deterministic as it suggests that rhythms are fixed by internal mechanisms.
Infradian & Ultradian Rhythms
- Ultradian: less than 24 hour cycle
- Infradian: More than 24 hours, monthly cycles
ULTRADIAN
Sleep Stages
- The first 4 stages are NREM: 1 and 2 are characterized by light sleep.
- Known as slow wave sleep (SWS) in stages 3 and 4.
- REM: this is a deep sleep shown as paradoxical sleep’, as the brain and eyes move, but the body is paralyzed.
Basic rest-activity cycle
- The 90-minute sleep cycle is located within a 24-hour rhythm.
- Freidman and Fisher observed eating/drinking behaviour in a 90-min cycle.
INFRADIAN
Monthly cycles
- The pituitary gland releases FSH. This releases LH, which stimulates oestrogen, and it releases preoestrogen which thickens the lining of the uterus.
Seasonal Affective Disorder
- SAD is a disorder that is characterised by depressive symptoms in the winder months that fades in the winter.
- This is due to the low levels of serotonin, which is characterized by depressive symptoms.
Evaluation
P: A strength comes from Dement and Kleitman (1957)
E: They demonstrated the link with REM and dreaming. Participants were likely to report dreaming during REM. This could potentially provide way to identify dreaming, to help explain it.
C: This strengthens the theory that REM is characterized with dreaming.
P: A strength of the basic rest-activity cycle is put forward as its shown to be there and important
E: This was found that the importance of this 90-minute rhythm Is a form of timing to ensure that biological processes work in unison.
C: This is a strength because it suggests that the 90-minute cycle is important.
P: A strength of the infradian rhythm is put forward by Russell et al.
E: In this study, a group of women has their sweat samples taken. It was then rubbed on the top lip of another group. They found that their menstrual cycles became in sync.
C: This is a strength because it’s shown that the synchronisation of the menstrual cycle is governed by pheromones.
IDA
This approach is very determinist as it removes the free will of the individual, assuming they will behave in a certain way, which ignores all other social factors that may be an issue.
Endogenous Pacemakers & Exogenous Zeitgebers
- Endogenous pacemakers: Internal cues
- Exogenous zeitgebers: Are external cues that entrain our biological rhythms.
ENDOGENOUS PACEMAKERS
The Suprachiasmatic Nucleus
- Located in the hypothalamus above the optic nerve.
- It obtains info about light through our eyes.
- Albus et al: 2005, states that the SCN is actually a pair of structures, one in each hemisphere of the brain, ventral and dorsal.
- Ventral portion is quicker to reset the external cues.
Basic rest-activity cycle
- 90-mins cycle, usually drinking.
EXOGENOUS PACEMAKERS
Light
- Most dominant zeitgeber.
- It can control the SCN and different oscillators because the protein CRY is light sensitive.
- Campbell and Murphy, 1998 – shining light at the back of participant’s knees, shifted their circadian rhythm.
Social Cues
- E.g: Mealtimes and bedtimes
- Davidson, 2006, the zietgeber for cells in the liver and heart is reset by mealtimes.
Temperature
- Cold temperature – time of reduced activity.
- Warm temperature – time for activity.
- Buhr et al, 2010, daily changes in body temperature are governed by own circadian clock and these temperature changes entrain other circadian rhythms.
Evaluation
P: Evidence to support the role of the SCN comes from Morgan 1995
E: He bred ‘mutant’ hamsters so their circadian rhythms was 20 hours, instead of 24 hours, then transplanted their SCN into a normal hamster. Those hamsters then displayed the mutant rhythms.
C: This shows how the SCN is the dominant endogenous pacemaker that is not affected by exogenous factors.
S: However, as this study was done on animals, it cannot be generalized to humans, as we are far more complex biologically.
P: However, there is evidence to go against the SCN as the main endogenous pacemaker.
E: Kate Aldcroft spent time in a cave, after 25 days her temperature was a 24-hour rhythm, yet her sleep rhythm was in a 30-hour-cycle.
C: Suggesting that the SCN is not in charge and doesn’t control all rhythms, and that something external may have affected the rhythms.
P: A study to support Light as a dominant zietgeber comes from Campbell and Murphy
E: They shifted circadian rhythms just by shining a light on the back of someone’s knees.
C: Thus suggesting that artificial lighting does have effect on entraining rhythms.
S: Further support comes from Boivin et al 1996 who found that circadian rhythms can be entrained by ordinary dim lighting, although bright light is more effective.
P: Stevens 2006 suggested that artificial light might have some negative consequences.
E: He stated that exposure to artificial lighting disrupts melatonin production, so women in industrialized areas are more likely to develop breast cancer.
C: Further suggesting that light affects our circadian rhythms.
P: Research to support the idea that social cues entraining rhythms comes from Fuller et al; 2008.
E: He found that adhering to social cues ceases symptoms of Jet Lag, possibly because some of our body clocks are reset by food intake.
C: Suggesting that social cues also play a part in entraining our rhythms.
IDA
However, most of the data collected derived from experiments with animal. Thus we are unable to fully generalize the findings to humans. Also, the biological approach is too deterministic, as it doesn’t take into account individual differences.
Consequences of Disrupting Biological Rhythms
- Shift Work: Shift work can be considered any scheduled work outside the 'normal' daytime hours of 7am to 7pm.
- Jet Lag: Used to refer to the physiological effects of disrupted circadian rhythms – even those that do not arrive from jet travel.
Shift Work
- Night workers often experience a circadian ‘trough’ of DECREASED ALERTNESS during their shifts – between 12am (cortisol = lowest) and 4am (core body temp = lowest)
- Workers who have to sleep in the day have SLEEP PROBLEMS because of other interruptions (noises/daylight) = usually sleep 1-2 hours less.
- REM in particular is affected.
- Relationship between shiftwork and organ disease – Knutsson et al found that individuals who worked more than 15 years are three times more likely to develop heart disease.
Jet Lag
- Symptoms: Loss of appetite, nausea, fatigue, disorientation, insomnia, mild depression.
- PERFORMANCE DECREMENT- Effects of jetlag found in study of American Major League baseball teams.
- Generally eastward flights (where there has been a phase advance of the circadian rhythm, ie. backward shift in the 24 hour cycle) cause greater problems than travelling west (where there is a phase delay, i.e. a forward shift in the 24 hour cycle.)
- Jet lag is less of a problem when travelling west because the body finds it less difficult adjusting to a slightly longer day than to a slightly shorter one.
- Even though the SCN can readjust its clock within the day, the effects of jet lag can last up to a month because internal clocks entrain at different speeds.
- This means that the central and peripheral clocks remain uncoordinated for some time.
Evaluation
P: A weakness of shift work is that there are other factors involved.
E: Shift work effects are not just due to the disruption of biological rhythms. They may be due to the lack of sleep associated with going to bed at odd hours. Experience social disruption, as they cannot spend time with family and friends. Divorce = as high as 60%.
C: Suggesting that there are other consequences to disrupting biological rhythms than shift work.
P: Another weakness of jetlag and shiftwork comes from Bovin et al.
E: Who looed at the power of lighting in resetting biological clocks. Used 31 males in 4 groups, who were ‘exposed’ to different conditions. Each group had advanced to a different degree, group one – 5 hours, group two – 3 hours, group three – 1 hour and group four – 1 hour LATER
C: Shows that even room lighting can have an effect on the circadian rhythm, not just jetlag or shift work
S: However, this experiment was conducted in a lab, thus having low mundane realism and may not be applicable to the real world.
S: Although, since the extraneous variables are controlled, they can be certain that the independent variable caused the dependent variable
P: Research evidence to support jetlag as a consequence from disrupting biological rhythms comes from Klein
E: He tested 8 participants flying between the USA and Germany. They found that adjustment to jet lag was easier for people of westbound flights than eastbound.
C: Suggests that the direction of the flight is and important factor in determining the effects of jet lag.
S: Further support comes from Schwartz who found that baseball sides from the east of the USA played better against teams in the west than western sides did playing against teams in the east. Supports phase advance.
P: A weakness of jet lag disrupting biological rhythms is that there are other factors involved.
E: Jetlag may also be affected by other factors, (other than disruption of biological rhythms). An individual may sleep badly the night before travel, because of worry/excitement. Travel itself is also tiring and many holidays include long trips to the airport before the flight. As well as alcohol, coffee and noise.
C: Suggesting that there are other factors that contribute to jetlag as well as disrupting biological rhythms.
P: A way of reducing the symptoms of jet lag is by taking melatonin.
E: Melatonin is a natural hormone that induces sleep. Herxheimer and Petrie 2001 reviewed 10 studies and found that when melatonin was taken near to a normal ‘bed time’, it was remarkably effective.
C: Thus it could be taken to induce sleep at a normal time in a new time zone.
IDA
However this is a biological approach and doesn’t take into account individual differences. Reignberg et al found that people who gave up shift work because they couldn’t cope tended to have rhythms that change a lot while on shift, whereas ‘happy shift workers’ had unchanging body rhythms.
The Nature of Sleep and Lifespan Changes
- As humans grow from infancy to old age, there are major changes in the amount and kind of sleep they experience.
Infancy
- Babies sleep the most at around 16 hours a day, but not continuously, they wake up every hr. or so, because their sleep cycles are shorter than the 90 min adult ones.
- They have immature versions of SWS and REM sleep called quiet and active.
- At birth about half of their sleep is active, and they go into deep sleep more gradually (around 20 mins) unlike adults who go fairly directly.
- By 6 months, the circadian rhythm is established, and by 1 yr. they sleep mainly at night, with a few naps in the day.
- Deep sleep increases and REM/active reduces.
- It is unknown whether REM/active is accompanied by dreaming, as they can’t report.
Childhood
- By 5 yrs. Children have EEG patterns that look like adults, but they still sleep more (around 12hrs. per day)
- They have more REM activity still (around 30% total sleep time)
- Boys sleep slightly more than girls.
- Not unusual for children to experience a variety of parasomnias e.g. night terrors.
Adolescence
- During childhood the need for sleep decreases, but in adolescence it increases to around 9 or 10 hrs. a night.
- Circadian rhythms change so that teens feel naturally more awake at night and more difficulty getting up early (phase delay)
- One distinguishing feature is that REM sleep for males is accompanied by orgasm and ejaculation, which is significantly less likely at other ages.
Adulthood and Old Age
- Normal adult sleep is usually 8 hours with 25% in REM sleep.
- Parasomnias are more rare but other sleep disorders e.g. insomnia and apnoea are more frequent.
- As age increases, sleep time remains around the same, but older people have more difficulty going to sleep and wake up more frequently (up to 6x a night), so they nap during the day to cater for this.
- The pattern of sleep also changes. REM decreases to around 20% and SWS is reduced to as low as 5%, other NREM sleep increases.
- Older people experience a phase advance of circadian rhythms, feeling sleepier in the evening and waking up earlier.
Evaluation
P: Babies may sleep longer as an evolutionary adaptation to make their parents lives easier, and allow them to get on with things that increase their survival chances e.g. cooking. They also may wake in the night because they need feeding, and if they didn’t they would go cold and hungry.
E: Infants higher REM/Active sleep may be because a significant amount of learning is taking place, as REM is associated with consolidation of memories and production of neurotransmitters.
C: Supported by the fact the premature babies spend 90% of their sleep in REM.
P: Sleep changes may be linked to hormone production.
E: These hormones are primarily released at night therefore sleep patterns are disturbed, leading to deprivation. Many correlates of sleep deprivation are thought to be typical of puberty e.g. moodiness, poor attention span, and irritability.
C: Suggesting that hormonal changes can also explain the upset to the circadian clock, described as delayed sleep syndrome. Crowley et al 2007
S: Wolfson and Carskadon 2005 recommended schools begin their day later to accommodate for the poor attention spans of adolescents in the early morning.
P: Recent studies have found there to be a mortality risk associated with too much sleep.
E: Kripke et al 2002 surveyed over 1 million adult men and women and found those only sleeping 6 or 7 hours had a reduced mortality risk, whereas those sleeping an average of 8 hours had a 15% risk, with those sleeping 10 hours having a 30% increase.
C: This suggests … ( I am not quite sure how to end this :S)
S: However this is only correlational data and therefore may not know the cause and effect.
P: Reduced sleep can also be explained in terms of physical sleep problems e.g. apnoea or medical illnesses.
E: Van Cauter et al 2000 stated, the fact that SWS is reduced, older people are more easily woken. The reduction of SWS leads to ta reduction in HGH; so this could explain some problems in older people, e.g. bone density and lack of energy. Sleep deficit in old age may explain why they experience impaired functions e.g. decreased alertness. Taking melatonin and other techniques can treat this.
C: Suggesting .. (also don’t know how to end this..)
IDA
However this theory is culture bias. Tynjälä et al 1993 looked at sleep patterns in 400,000 11-16 yr. olds living in different cultures in 11 European countries. Found that an important factor was the number of evenings spent outside the house, meaning they went to bed late and had little sleep because they had to get up early.
Shin et al 2003 found that Korean meal adolescent sleep time was 6.5 hours and Ghanizadeh et al 2008 found a mean time of 7.7.
Functions of Sleep: Evolutionary Explanations
- This theory suggests that sleep offers an adaptive function, and is therefore vital for survival.
- There are 4 main parts to the theory, these are:
- Predator avoidance
- Waste of time hypothesis
- Energy conservation
Energy Conservation
- Warm-blooded mammals expend energy to remain a constant temperature.
- This is an issue for small animals with high metabolic rates, as all activities require energy and high rated animals expend even more.
- Sleep offers a period of enforced inactivity, as this uses less energy.
- Backed up by the idea of hibernation. (Webb 1982 described it as the hibernation theory)
Predator Avoidance
- This suggests that an animal that is prey to another animal has a reduced sleep time (minimal for restoration purposes), as they must remain alert to avoid predation.
- A big predator (lion) can sleep for much longer as there is no threat of predation.
- The prey sleep as a vital function when they are least vulnerable.
Foraging Requirements
- Time spent sleeping may be constrained by food requirements.
- Herbivores eat plants, which is low in nutrients = more time eating and less time sleeping.
- Carnivores eat food high in nutrients allowing them to have time to sleep and conserve energy, as they do not have to eat continuously.
Waste Of Time
- Meddis 1975 suggested that sleep helps animals stay out of the way of predators when they are most vulnerable. E.g. during the night.
- Sleep merely ensures animals stay still when they have nothing better to do with their time.
- Young 2008 (Seigel) agreed with this, suggesting that being awake is riskier because the animal is more likely to get injured., and also that sleep enables energy conservation and remaining out of danger and so offers the best chance of successfully passing on genes.
Unilateral Sleep
- Sleep isn’t just adaptive but also the patterns of sleep.
- The differences in sleep patterns tell researchers about different selective pressures facing a specific species, with different sleep patterns being an adaptive response.
- An example of adaptive sleep patterns is unilateral sleep. This is where one hemisphere of the brain is awake while the other is asleep. This has evolved in some marine animals and migrating birds to cope with particular selective pressures.
REM and NREM Sleep
- In REM sleep the brain is relatively active, whereas in NREM it is inactive, and so suggests that it is only NREM sleep that has evolved for energy conservation.
The phylogenetic signal
- This is behavioural similarity between species close on the phylogenetic scale.
- Research has found that mammalian species that are genetically close have more similar sleep patterns than would be expected. (Capellini et al 2008)
Evaluation
P: Support for Predator avoidance comes from Allison and Cicchetti 1976
E: Who found that species who had a higher risk of predation did sleep less, although there were some exceptions e.g. rabbits who had a high danger rating, but slept as much as low rated moles.
C: Supporting the idea of predator avoidance when it comes to animals surviving.
P: However recent research by Capellini et al 2008 accused older research of not using standardised methods , and so carefully selected data to carry out a meta analysis.
E: They found a negative correlation between metabolic rate and sleep, which doesn’t support the theory.
C: Thus showing there to be more than just evolution behind the need and function of sleep.
P: Mukhametov 1987 supports unilateral sleep
E: He found that dolphins had to come up to the surface to breath, and so could not fall in deep sleep underwater or they would drown. So they adapted their sleep to unilateral, so the brain hemispheres would swap every two to three hours.
C: Thus supporting the idea that certain animals adapt to their surroundings in order for them to survive.
P: Support for Energy conservation comes from Zepelin and Rechtschaffen 1974
E: They compared sleep habits across species to investigate the costs and benefits. They found that smaller animals with higher metabolic rates sleep more than larger animals. C: This supports the view the energy conservation may be the main reason for sleep, although there are some exception e.g. the sloth, who sleep 20 hours a day, despite begin large.
P: Allison and Cicchetti 1976 support NREM and REM sleep
E: They found that larger animals had less NREM sleep, but not less REM sleep.
C: This shows that it is important for conservation.
* P: However Capellini et al found no correlation between body size and NREM sleep.
E: This is further supported by more primitive animals e.g. reptiles, who only have NREM sleep.
C: This suggests that NREM evolved first and was adapted as a way of conserving energy, whereas REM may have evolved later as a way of maintaining brain activity.
IDA
Horne 1988 put forward a theory that combines elements from restoration and evolutionary theory. He suggested a distinction between core and optional sleep. Core sleep is mainly SWS and vital for restoration of body and brain, whereas optional sleep in mainly REM and has the function of occupying unproductive hours and conserving energy.
- A sleep disorder is any condition, which involves difficulty sleeping, insomnia being one of the most common.
- Short-term Insomnia: Some people suffer insomnia for a short period of time (days/weeks). This tends to be caused by immediate worries e.g. an exam.
- Long-term (Chronic) Insomnia: This is insomnia that lasts for more than 4 weeks (DSM definition). There is then a distinction made between primary and secondary insomnia.- secondary is more common.
Primary Insomnia
- This is sleeping problems not directly associated with a health condition or physical cause.
- They may feel stressed/depressed, but these are not the cause of insomnia, perhaps an effect.
- They may have developed the sleeping problems through bad sleeping habits e.g. staying up late.
- Sometimes they may have had an identifiable cause for the insomnia before that has now gone, but the insomnia persists because of the expectation of their inability to sleep.
Secondary Insomnia
- This is sleeping problems as a result of something else. (a single underlying medical/physical/ environmental cause) and so is a symptom of the main cause.
- Insomnia is also typical of people with circadian rhythm disorders such as phase delay syndrome (i.e. shift workers) where the abnormal rhythm causes sleepiness at inappropriate times.
- Older people often suffer from insomnia due to discomfort while sleeping from medical disorders e.g. rheumatism. They also struggle to seep because of their reduced SWS, meaning they are more easily woken.
- Insomnia can also be the result of environmental factors e.g. too much caffeine or alcohol.
- Other sleep disorders (parasomnias) can cause insomnia e.g. sleep apnoea, where the person stops breathing up to 30 times an hour, and so sleep is disrupted.
Teenage Insomnia
- Teenage insomnia may be the result of the shift in the circadian rhythm-a circadian phase disorder
- Roberts et al 2008 found that teenage insomnia was a major problem, as common as substance abuse and depression. They analysed data from over 4000 adolescents aged 11-17 from Texas and found 25% of the young people had symptoms of insomnia and 5% reported a lack of sleep interfered with their ability to function in the day.
- In a follow up study, of the teens with symptoms 41% still had the symptoms a year later.
Primary VS Secondary Insomnia.
- If insomnia is the symptom of another disorder, it is important to treat that, rather than the insomnia.
- However it may not be that simple to work out the cause of someone’s insomnia e.g. does depression cause insomnia or insomnia cause depression.
Consequences Of Insomnia
- The detrimental effects of it show the importance of treating the disorder.
A Model to Explain Insomnia-
- Speilman and Glovinsky 1991 offer a distinction between predisposing, precipitating, and perpetuating factors in their model.
- Predisposing - suggests a genetic vulnerability for insomnia.
- Precipitating - events that trigger the disorder in vulnerable individuals. E.g. environmental factors such as stress or jet lag.
- Perpetuating - factors that maintain insomnia when the original cause of it has gone. Epsie 2002 suggests these factors are the key to chronic insomnia.
P: A study to support/weaken Insomnia comes from Ohayon and Roth 2003
E: They found that, in a study of almost 1500 Europeans, insomnia more commonly preceded than followed mood disorders.
C: This means that for some people, it may be helpful to treat the insomnia, whether it is a primary or secondary effect.
P: Insomnia could cause cognitive impairment e.g. poor concentration and memory loss.
E: Zammit et al 1999 found that patients with insomnia scored lower on the Medical Outcomes Study Cognitive Scale than the control patients, showing problems with memory, reasoning, problem solving and concentration.
C: Suggesting that insomnia may likely lead to harsh consequences.
P: Insomnia may also cause severe accidents. Sleepiness and cognitive issue make a risk for safe driving.
E: Arendt et al 2001compared the performance of adults deprived of a day of sleep with some given alcohol, and found that even keeping people awake for 3 more hours than usual lead to impairments equivalent to modest alcohol levels.
C: Thus showing how insomnia could have detrimental consequences to people’s lives.
P: Insomnia could also cause psychological disturbances.
E: Its possible that insomnia is actual the cause of some psychological problems e.g. depression, rather than the effect. Including drug and alcohol abuse (Breslau et al.)
C: Suggesting the insomnia could be the root of some psychological problems.
P: Insomnia also causes the Immune system to under function.
E: Savard et al 2003 found that in Canada, there were fewer immune cells in the people suffering chronic insomnia than in good sleepers.
C: Thus suggesting that insomniacs more prone to illnesses.
S: However there is an issue with cause and effect, as if stress is the cause, then stress affects the immune system as well.
P: Evidence to support predisposing factors comes from twin studies.
E: Watson et al 2006 who found that 50% of the variance in the risk for insomnia could be attributed to genetic factors.
C: Suggesting that insomnia could be the result of genetics.
S: Research also suggests that physiological factors may predispose people to develop insomnia.
IDA
One of the causes of primary insomnia is the person’s belief that they will have difficulty sleeping. A clever way to treat this is to by the attribution theory method, where the person who has learnt to attribute their sleeping difficulties to insomnia can be convinced the source is elsewhere, and so ends their dysfunctional attribution.
Explanations of Other Sleep Disorders
NARCOLEPSY
- Narcolepsy is a disorder where the individuals experience sudden, irregular and unexpected attacks of uncontrollable sleep.
- It can last for seconds or minutes and is often triggered by stressful situations.
- Psychological explanations - an early approach to narcolepsy looked at psychological issues e.g. Lehrman and Weiss 1943 suggested sudden attacks of sleepiness disguised sexual fantasies.
REM
- One of the classic symptoms of narcolepsy is loss of muscle tone (cataplexy), this is similar to what happens in REM.
- Also during the day, Narcoleptics experience REM type sleep (hallucinations). At night they have abnormal REM sleep.
- In the 1960s the explanation offered suggested narcolepsy was caused by a malfunction in the system regulating REM.
HLA
- HLA variant – HLA-DBQ1*0602
- In the 1980s it was suggested that narcolepsy was linked to a mutation of the immune system.
- Honda et al 1983 found increased frequency of one type of HLA in narcoleptics.
- These molecules are found on the surface of WBCs and coordinate the immune response.
- Recent research has found that over 90% of narcolepsy suffers with cataplexy have the HLA variation. (Stanford Medical Centre 2012). [Causality issues]
HYPOCRETIN
- Most recently researchers have found a link between the neurotransmitter (Hypocretin) and narcolepsy.
- This transmitter regulates sleep and wakefulness through interaction with systems regulating emotion and homeostasis in the hypothalamus.
- Sakurai 2007 found in Narcoleptics a large number of the cells producing Hypocretin are missing, and so there is underproduction of it.
Evaluation
P: REM is supported by Vogel 1960.
E: Who observed REM at the onset of sleep in a narcoleptic patient, compared to it normally occurring in the later stages of sleep.
C: Further supporting the explanation of REM.
S: Further support comes from Seigel 1999, who found that Cataplexy in dogs co-occurred with brain cell activity associated with REM. However, generally the research is unconvincing.
P: There has been evidence to weaken HLA as a common variant in narcoleptics.
E: The specific HLA variant is not found in all narcoleptics, and is reasonably common in the general public.
C: Suggesting it cannot be the sole cause.
P: Evidence for lower levels Hypocretic causes narcolepsy came from narcoleptic dogs.
E: Who had a mutation on chromosome 12, leading to a disruption of the processing of Hypocretin (Lin et al 1999).
C: Suggesting that low levels of Hypocretin cause narcolepsy.
S: These findings have been confirmed in human studies, where they found for example, lower levels of Hypocretin in their cerebrospinal fluid. (Nishino et al 2000).
P: However, there has been a lack of evidence to support narcolepsy as being inherited.
E: Hypocretin loss in humans is rarely due to only 1 gene and does not appear to be inherited due to lack of conclusive twin evidence. More likely that it is caused by brain injury, illness, diet, stress and possibly autoimmune attacks.
C: Weakening the theory that Hypocretin is inherited and causes narcolepsy.
P: Linking Hypocretin to HLA
E: Autoimmune attack links to involvement of HLA as mutations of HLA affect the immune response and so make the attacks more likely, maybe resulting in reduced number of Hypocretin cells. (Mignot 2001)
C: Suggesting that HLA and Hypocretin play a part together in causing narcolepsy.
IDA
Real world applications - Researchers are trying to create an artificial drug to replace the missing Hypocretin in the brains of narcoleptics. This is not a cure, but a way of controlling narcolepsy. Possibly in the future there may be a way of transplanting Hypocretin cells into narcoleptics brains.
Aggression
Social Learning Theory (SLT)
- Bandura and Walters (1963) – aggression not explained using traditional learning theory.
- SLT – we learn by observing others – learn specific of aggressive behaviour.
- Role of bio factors not ignored.
Social Learning Theory
Observation
- Children learn aggressive response through observation.
Mental Representation
- Bandura (1968) – for learning to take place a child must form a mental representation of events.
- Child must represent possible rewards and punishments.
Production Of Behaviour
- If a child is rewarded for a behaviour he/she will repeat it.
- A child who bullies successfully will attach value to aggression.
- Child will develop confidence in ability to carry out violent actions.
- Those who have not been able to use this behaviour have less confidence in ability to use aggression.
Bobo Doll Study
- Aims: Investigate SLT children observe aggressive/non-aggressive, models tested for imitative behaviour.
- Procedure: Participants 3-5, half exposed to aggressive model, the other half exposed to a non-aggressive model.
- Model who displayed aggressive behaviour to doll – hit it and were verbally aggressive.
- Following exposure to doll, children made to be frustrated. They were shown toys they could not play with. They were than taken to a room with the Bobo doll and toys.
- Findings: Children in aggressive condition were physically and verbally aggressive.
- Children in non-aggressive condition were not aggressive towards the doll.
- No gender differences in imitation of verbal aggression.
- Conclusion: Actual expression of aggression is learned by observing others.
- Criticism: Selection bias – study done in Stanford, upper middle class whites, doesn't account for lower classes.
- Unethical – long term implications, children had been manipulated
Evaluation
P: Phillips (1986) supports SLT
E: Daily homicide rates in the US increase in the week following a boxing match. Viewers imitated behaviours seen.
C: Social learning theory is evident in adults as well as children.
S: Does not take into account other extraneous variables.
P: Another support is that it can explain aggressive behaviour in absence of reinforcement.
E: Although participants behaved aggressively after observing models, at no point were they rewarded.
C: Shows vicarious learning is necessary – children learn about consequences.
S: Does not account for individual differences.
P: More support comes from Wolfgang and Ferracuti (1967) – can explain differences.
E: Propose in large societies, some subcultures develop norms that sanction violence to a greater degree than dominant culture.
C: Shows people respond differently to different situations.
P: However, SLT can be used to explain cultural differences in aggression.
E: Among !Kung San or the Kalahari Desert aggression is rare. Answer lies in child rearing practices. When children argue, parent neither reward or punish them, separate them.
C: Shows cultural differences.
IDA
- Ethical issues make it hard for SLT to be tested. Exposing children to aggressive behaviour is wrong, psychological and physical harm.
- Selection bias – subjects from Stanford University. During 1960s only upper middle class whites go there.
Deindividuation
- Gustave le Ban (1865) – classic crowd theory.
Nature Of Deindividuation
- Psychological state characterized by low self-evaluation.
- It is aroused when individuals join crowds – factors involved include anonymity (wearing uniforms) and altered consciousness.
Process Of Deindividuation
- Some refrain from acting aggressively due to social norms.
- Being anonymous in a crowd can reduce inner restraints.
- Zimbardo suggests being in a crowd diminishes awareness of our individuality.
- In a large crowd, each person is faceless and anonymous.
Research On Deindividuation
- Anonymity – Zimbardo (1969) – carried out a series of experiments.
- Rehm et al (1987) – investigated whether wearing a uniform increased aggressive behaviour. Put German school children in teams of 5, half given orange shirts and the other half normal shirts. Those is orange more aggressive.
- Faceless crowd – Millen (1986) – analyzed newspaper cuttings on 60 lynching in the US. The more people in the crown the greater the savagery.
Reduced Self Awareness
- Prentice-Dunn et al. (1982) – reduced self-awareness leads to deindividuation.
Evaluation
P: Postmes and Spears (1998) weaken the theory.
E: Their meta-analysis of 60 studies found that antisocial behave is not more common in large groups.
C: Limited support for deindividuation,
P: Support comes from Robert Watson (1973)
E: Collected data on the extent to which warriors in 23 societies changed their appearance prior to going to war. Societies where they changed their appearance were more destructive to their victims.
C: Changing your appearance = more likely to act aggressively.
S: Recognises cultural differences.
P: Zimbardo (1969) supports the theory.
E: Group of 4 female undergrads required to deliver electric shocks. Half participants wore bulky coats and hoods and were not referred to by names. Other half was given name tags and could see each other.
C: Those in deindividuation condition gave shocks for twice as long.
S: Gender bias.
P: Spivey and Prentice-Dunn (1990) – increase pro-social behaviour as well.
E: Found deindividuation can lead to pro-social behaviour. When pro-social environmental cues were present participants performed altruistic acts.
C: Depending on the environment your deindividuation doesn’t need to lead to anti-social behaviour.
P: Mann (1981) supports the theory.
E: Analysed 21 suicide leaps in the US, 10/21 cases when a crowd watched, occurred at night.
C: It shows being part of a crowd caused deindividuation.
S: Cultural bias.
Institutional Aggression
- Within prisons – importation model.
Institutional Aggression Within Groups: Prisons
Interpersonal Factors
- Irwin and Cressey (1962) – claim prisoners bring their own traits to prison.
- Prisoners are not ‘blank slates’ when they enter prison.
Gang Membership
- Gang memberships relates to violence – pre-prison gang membership key determinant of prison misconduct.
- Huff (1998) – gang membership in the UK 10x more likely to commit murder and 3x more likely to assault someone.
Situational Factors – The ‘Deprivation Model’
- Prisoner/patient aggression due to stressful and oppressive conditions. (Patterline and Peterson 1999)
- Trainee nurses more likely to be assaulted than trained ones (Hodkinson et al 1985)
The Pains Of Imprisonment – Sykes 1988
- Specific deprivations inmates experience within prison – may link to an increase in violence.
Institutional Aggression Within Groups: Genocide
- Genocide – deliberately killing a large amount
- 5 stages of genocide Staub (1999) 1) different social conditions, 2) Scapegoating, 3) negative evaluation, 4) moral values inapplicable, 5) passivity of bystanders.
Dehuminisation
- Humans have moral inhibitions about killing others – changed if target group are dehuminised.
Obedience to Authority
- Milgram believed the holocaust was the result of situational pressures, that forced the Nazi soldiers to obey leaders, regardless of personal or moral repugnance
Evaluation
P: Harer and Steffensmier 2006 support the importation model in terms of individual factors.
E: They collected data from 58 US prisons. Black inmates = significantly higher rates of violent behaviour, lower rates of alcohol/ drug-related misconduct than white inmates. C: These patterns parallel racial differences in these behaviours, supporting the model.
P: Evidence to support claim that peer violence is used to relieve deprivation from institutions such as prison.
E: McCorkle et al. 1995 found that overcrowding, lack of privacy and the lack of meaningful activity all significantly influence peer violence.
C: Supporting the deprivation model.
S: However, research in psychiatric institutions is not consistent with this.
S: Ninja et al. 1999 found that increased personal space failed to decrease the level of violence among patients.
P: Bellisiset et al (2004) weakens gang membership theory.
E: Found inmates with gang involvement were not more likely to get involved than other inmates.
C: Suggesting that Gang membership doesn't pre-determine what happens in prisons.
S: Fisher 2001 – isolating known gang members reduced serious support. Weakens the research.
P: Stuabs model emphasises importance of bystander intervention in preventing genocide.
E: Doing nothing it appears, merely allows killing to continue. May escalate it by signaling consent.
C: However, bystander intervention does not necessarily end institutional aggression. Intervention can shorten conflict but may also hasten perpetrators to step up their genocidal policy within that period of time. (Rwandan genocide - 8,000 deaths per day).
P: Obrien 2003 claims that dehumanisation may explain violence against immigrants, seen by some as 'polluting threats to the social order'.
E: Esses et al. 2008 has demonstrated that individuals high in social dominance orientation have a tendency to dehumanise out-group members. (refuges, asylum seekers).
S: Supporting the theory that dehuminisation causes aggression within groups.
P: Mandel 1998 challenges Milgram's claim.
E: He argues that his account is mono-causal and does not match historical record.
C: Weakening Milgram’s theory of obedience to authority.
S: Goldhagen 1996 suggests that the main causal factor in Holocaust was a form of anti-Semitism.
Neural And Hormonal Mechanisms
Neural Mechanisms
- Biological explanations suggest that aggressive behaviour can be in the makeup of an individual rather than in the environment around them.
Serotonin
- Biological explanations suggest that aggressive behaviour can be in the makeup of an individual rather than in the environment around them.
- Low levels of serotonin are associated with aggressive behaiour.
- Serotonin usually reduces aggression by inhibiting responses to stimuli that might otherwise lead to aggressive behaviour.
- Low levels of serotonin have been associated with an increased susceptibility to impulsive and aggressive behaviour.
- Mann et al: gave 35 healthy people dexfenfluramine (reduced levels of serotonin). Using a questionnaire he found that the drug caused men to become violent and aggressive.
Dopamine
- Increases in dopamine levels have been shown to produce increases in aggressive behaviour.
- Demonstrated in a study by Levine, used amphetamines (to increase dopamine activity in the brain) and found an associated increases in levels of aggressive behaviour.
Hormonal Mechanisms
- Testosterone is a male sex hormone and is thought to influence aggression from young adulthood onwards due to its action on the brain areas involved in controlling aggression
Testosterone
- Is thought to increase aggression
- Wingfield et al: Monogamous species levels should only raise above the baseline breeding level in response to social challenges such as male-male aggression or threat to status.
- Dabbs et al: Salivary testosterone in violent and non-violent criminals: Those with the highest testosterone levels had history of primarily violent crime; those with lowest testosterone had non-violent crimes.
Cortisol
- High levels of cortisol inhibit testosterone levels and so inhibit aggression
- Low levels of cortisol have been reported in habitual violent offenders – Virkkunen.
- And in violent schoolchildren - Tennes and Kreye.
- This suggests that, although testosterone may be the main biochemical influence on aggressive behaviour, low cortisol levels increase the likelihood of aggressive behaviour.
Evaluation
P: Scerbo and Raine support for the importance of serotonin
E: A meta-analysis of studies found that lower levels of serotonin in individuals were described as being aggressive.
C: This supports the claims that serotonin depletion leads to impulsive behaviour, which leads into aggressive behaviour in various forms.
P: Evidence for the importance of serotonin comes from studies of animals that have been specially bred for domestication and for increasingly docile temperaments.
E: These animals have shown a corresponding increase, over generations, of levels of serotonin in the brain.
C: Supports the idea that high levels of serotonin block the stimuli that may lead to aggressive behaviour.
P: Evidence for dopamine as cause for aggression is inconclusive.
E: A study by Couppis and Kennedy rat study found that some individuals might seek out aggressive encounters because dopamine is increased as a positive reinforce in the brain when they engage in aggressive behaviours.
C: Suggesting that dopamine is more of a consequence of aggression rather than a cause
P: However, Scerbo and Rain challenges this theory.
E: A meta-analysis examined neurotransmitter levels in antisocial children and adults. They found lower levels of serotonin in individuals described as aggressive, but found no rise or fall of dopamine levels in this group compared to normal individuals.
C: Suggesting that dopamine has no effect on levels of aggression.
P: Albert et al. (1993) state that there is inconclusive evidence for the link between testosterone and aggression.
E: Some studies find no relationship between testosterone and aggression, most studies give small samples.
C: Not enough evidence to support testosterone.
P: Manzur (1985)
E: We should distinguish between aggression and dominance. Individuals act aggressively when they want to cause pain. Aggression is a form of dominant behaviour.
C: Aggressive behaviour may not be a reason of increase in testosterone.
Genetic Factors In Aggression
- Aggression inherited – genetic factors = a question of nature and nurture.
- Nature being genetic inheritance & Nurture being environmental influence.
Twin Studies
- Monozygotic twins share all genes/ dizygotic share 50%.
- Studies on twins focused on criminal behaviour.
- 50% variance in direct aggressive behavuour could be contributed to genetic factors. Coccaro et al (1997)
Adoption Studies
- Help to untangle the relative contributions of environment and heredity in aggression.
- If a positive correlation is found between aggressive behaviour in adopted children and their biological parents, a genetic factor is implied.
- Study of over 14,000 adoptions in Denmark. Adopted boys with criminal convictions had biological parents with criminal convictions. (Hutichings and Mednick (1975)
Role Of MAOA
- Associated with aggression.
- Regulates metabolism of serotonin in brain, low levels associated with aggression.
- 1980s – Dutch family, male members behaved violently and aggressive. A large number had been involved in crimes. These men have low levels of MAOA – a defect in this gene was found – Brunner et al. 1993
Genetics And Violent Crimes
- Researches do not suggest there’s a gene for violent crime.
- Its claimed its inherited, temperamental, or personality characteristics.
- Adoption studies show highest rates of criminal behavior, occur when biological and adoptive parents have history of violence.
Evaluation
P: Support comes from Miles and Carey (1997) – genetic basis.
E: Meta-analysis of 24 studies. Results = strong genetic influence, could count for 50% variance in aggression.
C: Shows genetics is a factor.
S: Ignores extraneous variables.
P: Further supports comes Rhee and Waldman (2002)
E: Meta-analysis, combines results of 51 studies, concluded aggression, anti social behaviour a product of genetics.
C: Shows genetics is a factor.
P: Plomin et al. (1981) weaken twin studies.
E: Twin pairs were encouraged to act aggressively to Bobo doll, by being exposed to an aggressive model. No difference in correlation.
C: Shows individual differences.
S: Ethical issues, protection from harm.
P: Walters (1992) argue against a gene in aggression.
E: Low correlation between hereditary and crime.
C: Data does not suggest there is a link between hereditary violence.
S: Extraneous variables not taken into account.
IDA
- Animal research – Young et al. 2002 – rodents offer advantage of experimental manipulation – may include selective breeding and knockout techniques.
- If people are predisposed to aggression then genetic engineering should be advocated. Some say there should be chemical castration.
Evolutionary Explanations
Jealousy
- Daly and Wilson – men evolve strategies to deter female partners from committing adultery
- Range from vigilance, violence – fuelled by male sexual jealousy, adaption evolved to specifically deal with threat of parental uncertainty
Cuckoldry And Sexual Jealousy
- Men never entirely certain child is theirs – fertilisation hidden – risk of cuckoldry
- Consequence – child not their own, investing in resources on a child not theirs
- Sexual jealousy functions – deters mate from infidelity, lower risk of infidelity
Mate Retention And Violence
- Buss – to keep a mate – restrict partner’s autonomy, threats of threats – prevents straying
- Sexual jealousy primary cause of violence – those perceived as more threatening to infidelity more at risk of violence
- Dobash and Dobash – in majority of domestic violence cases in women, jealousy on male’s part key cause of violence towards woman
Sexual Jealousy And Extreme Violence
- Daly – male sexual jealousy single most common motivation for killings in domestic disputes in US
- Dell – 17% of murders in UK sexual jealousy
- 8 studies summary of love triangle same-sex killings – 92% male-male murders, 8% female-female murders
Infidelity
- Daly – detection/suspicion of infidelity primary cause of violence
- BBC the Love Map – 1 in 10 females admitted to being unfaithful to husbands, although mostly husbands being unfaithful
Sexual Coercion
- Goetz – men’s perception/suspicion of wives’ infidelity is sexual coercion or partner rape
- Camilleri – sexual assault on female by male partner linked with perceived link to infidelity
- Shields and Hanneke – female victims of partner rape more likely to report engaging in extra-marital sex than those not raped by partner
Violence Toward Pregnant Partner
- Infidelity sometimes leads to pregnancy – when child born, long-term mate risks investing in offspring of another male – lower reproductive success
- Violence towards pregnant partner is to try and terminate pregnancy - eliminating potential offspring of rival, leaves free to bear their own offspring
Uxorocide (Wife Killing)
- Men guarding against partner infidelity by conferring benefits or inflicting costs, including violence
- Shackelford – men possessing fewer resources more prone to becoming violent
- Daly and Wilson – death of partner from physical violence may be unintended outcome of evolutionary adaption that was designed for control rather than death
Evaluation
P: Shakelford study particular tactics used by men are early indicator of violence.
E: Findings can be used to alert friends and family to danger signs, specific acts that lead to future violence in relationships.
C: Help sought or offered before violence happens
P: Takahashi supports male sexual jealous as a link to aggression.
E: neural response to imagined scenes of sexual infidelity and emotional infidelity different for men and women – men greater activation of amygdale and hypothalamus when sexual, women same but for emotional
C: Supporting the link between sexual jealousy and aggression.
P: Edlund and Sagarin argue that research is insufficient.
E: It doesn’t tell us whether locus of responsibility moderates the jealous response.
C: Suggesting that the research doesn’t say whether degree of perceived infidelity is important
P: Camilleri supports the link between infidelity and partner violence.
E: Risk of partner’s infidelity predicts sexual coercion among males, not females. Males risk of cuckoldry, not females.
C: Supporting the link that infidelity may lead to aggression.
S: Camilleri and Quinsey – men convicted of raping partners more likely to experience cuckoldry risks prior to offence compared to men convicted of non-sexual partner abuse
P: Further support of sexual jealousy comes from Burch and Gallup
E: Frequency of violent acts toward partners who were pregnant around double than those not pregnant, sexual jealousy characterising men who committed violence against pregnant partners.
C: Supporting the link between sexual jealousy and aggression in partners
S: Taillieu and Brownridge – women abused while pregnant more likely to be carrying child of a man other than partner.
IDA
- Evolutionary perspective doesn’t explain why people react differently when faced with same adaptive problem
- Buss and Shakelford – cannot account for why different males respond in different ways when faced with infidelity – some may be violent, some may kill, some may get drunk
Group Display As An Adaptive Response
Sports
Xenophobia
- Wilson (1975) – xenophobia documented in every group of animals displaying higher forms of social organisation.
- Natural selection – favoured genes that caused human beings to be altruistic toward a member of their group.
Territoriality
- Common in many species.
- Threat display towards outsiders. There is human equivalent = sports teams.
- Testosterone and territorial behaviour is another group.
- Neave and Wolfson (2003) – teams at home are more likely to win than those not at home.
- Evolved drive to defend territory.
Warfare
- Any behaviour associated with warfare leads to the assumption it has evolved because of adaptive benefits.
Benefits Of Aggressive Display
- In societies that experience frequent warfare, males likely to escape infanticide than females, due to worth. Since there are few women men have to compete – display of aggressiveness attractive to females.
Status
- Earn more respect is seen as aggressive.
Costly Displays – Signals Of Commitment
- Primary function of ritual displays is promotion or group solidarity
- Irons (2004) – scares and mutilations are signals commitment.
- Warfare minimizes defection – during battles humans’ adaptive response is to keep him safe, putting others at risk.
- Permanent scares do not allow males to defect from group.
Evaluation
P: Foldessi (1996) support the link between xenophobia and violent displays.
E: Hungarian football crowds - Racist conduct of extremist supporters led to increased spectators violence.
C: Supporting territorial displays.
S: Culture bias.
P: Lewis et al. (2005) support testosterone and territorial behaviour.
E: Among football fans, crowd support rated significant factors contributing to home advantage. Fans felt responsible for victory.
C: Supporting territorial behaviour.
S: Pollard and Pollard (2005) – displays of support hard to pinpoint.
P: Moore and Brylinsky (1993) – challenges home crowd advantage.
E: Measles Epidemic – 11 American basketball games for 2 teams played without spectators. Siena Saints NY nine games away, 5 with and 4 without spectators. Hartford Hawks Connecticut, 11 games, 4 without and 7 with. Siena Saints averaged 76:25 with and 86:70 without, Hartford Hawks 64:29 with 71:25 without.
C: Displays of support for home team crowds did not increase performance.
P: Warfare – Palmer and Tilley (1995) support sexual selection.
E: Male youth gang members had more sexual partners than normal young males.
C: These males were seen more attractive because of status.
S: Leunissen and Van Vught (2010) – military men greater sex appeal only if observed. Issue with criteria that actually watched them right.
IDA
Gender bias – Adams (1983), does not reflect women’s behaviour adequately. Idea of women warrior unheard of. Rare for them to fight, therefore the understanding is limited.
Success and failure of dieting
RESTRAINT THEORY – HERMAN & MACK (1975)
The Restraint theory `was an attempt to explain both the causes and consequences associated with the cognitive restriction of food intake. They suggested that attempting not to eat actually increases the probability of over-eating.
BOUNDARY MODEL – HERMAN & POLIVY (1984)
In an attempt to explain why dieting, might lead to overeating they created the boundary model. Model explains the failure of dieting in terms of the greater distance between hunger and satiety in dieters. It takes dieters longer to feel hungry and therefore more food to reach a state of satiety. In addition, dieters have a self-imposed desired intake. Unlike non-dieters, when they go over this threshold of desired intake, they experience a ‘what the hell’ effect, and continue to eat until they reach satiety, i.e. beyond the maximum level imposed as part of their diet.
RESEARCH SUPPORT – WARDLE & BEALES (1988)
Assigned 27 obese women to 1 of 3 groups for 7 weeks; restrained eating, exercise or non-treatment group. Women in restrained eating group ate more than women in other 2 groups.
LIMITED RELEVANCE – OGDEN argues that restraint theory may explain the overeating of some groups with disordered eating patterns (e.g. dieters, bulimics) HOWEVER the behaviour of restricting anorexics can’t be explained in this way. If trying not to eat results in overeating, claims Ogden, then how to restricting anorexics manage to starve themselves?
OBEISTY TREATMENTS BASED ON RESTRAINT MAY FAIL BECAUSE restraint theory suggests that restraint leads to overeating, yet the treatment of obesity typically recommends restraint as a way of losing weight. As a result, overeating may be a consequence of obesity treatment, leaving many obse individuals depressed, feeing a failure and unable to control their weight.
CULTURAL BIAS IN OBEISTY RESEARCH – IDA
Some cultural groups appear to find it harder to diet successfully because of a natural inclination to obesity. Asian adults are more prone to obesity than Europeans (PARK ET AL). Asian children and adolscents have a greater central fat mass compared to other ethnic groups (MISRA ET AL.)
FREE WILL OR DETERMINISM – BORN TO BE FAT? – IDA
It is likely that a number of genetic mechanisms exert an influence on weight, suggesting that the success/failure of dieting may be determined by factors other than an individual’s choice of lifestyle. One such gene codes for lipoprotein lipase (LPL), an enzyme produced by fat cells to help store calories as fat. LPL also makes it easier to regain lost weight.
THE ROLE OF DENIAL
Research in cognitive psychology has shown that attempting to suppress or deny a thought frequently has the opposite effect. WEGNER suggests any attempt to suppress thoughts of forbidden foods only increases the dieter’s preoccupation with the very foods they are trying to deny themselves. As soon as food is denied, therefore, it becomes more attractive.
THEORY OF IRONIC PROCESSES OF MENTAL CONTROL
Attempting to suppress a thought frequently has the opposite effect, making it even more prominent. Central to any dieting strategy is the decision not to eat certain foods. This results in a state of denial as dieters attempt to suppress thoughts about foods ‘forbidden’ as part of their diet.
RESEARCH SUPPORT - WEGNER ET AL.
Asked some participants NOT to think of a white bear, but to ring a bell if they did, and others to think about the bear. Results: those told NOT to think about the bear rang their bells far more often than PP’s who were asked to do so.
RESEARCH SUPPORT – SOTENS ET AL.
Found that participants who suppressed thoughts about food also showed a rebound effect, and were more likely to think about food after suppression. This might explain why denial of thoughts about food leads to greater than less preoccupation with it.
FREE WILL OR DETERMINISM – IDA
Some people find dieting ineffective because they have high levels of lipoprotein lipase, which makes body more effective at storing calories.
MAY BE GENDER DIFFERENCE IN LPL ACTIVITY
Research suggests that sex hormones play a part in LPL activity, e.g. oestrogen inhibits LPL activity, which explains why women put on weight after menopause when oestrogen levels are lower. A consequence of this is that dieting through restraint or denial may be more difficult for post-menopausal women for purely biological reasons.
REDDEN claims that people usually like experiences less when they have to repeat them constantly. When it comes to dieting, this makes it harder to stick to a particular regime. However, by focusing on the specific details of each meal, people get bored less easily and are better able to maintain their diet.
REAL WORLD APPLICATION – IDA
This has led to the development of anti-diet programmes aimed at replacing dieting with conventional eating. These emphasise regulations of eating by body hunger and satiety signals rather than the development if inappropriate attitudes to food (e.g. denial or restraint), which have been shown to be ineffective at weight control.
A meta-analysis of the effectiveness of anti-dieting programmes (HIDDINS & GRAY) found that they could improve both eating behaviour and psychological well-being, and led to weight stability rather than weight change.
The Environment of Evolutionary Adaptation
- EEA refers to the environment in which a species first evolved.
- Preference for fatty foods was adaptive because harsh conditions in the EEA meant that for early humans energy resources were vital to stay alive.
- Early humans evolved a preference for foods that were particularly rich in calories (fatty/sweet foods)
- The adaptive problems faced by our ancestors in the EEA would have shaped early food preferences.
- For most of human history, human beings would have lived in hunter-gathering societies, which would have led to a preference for high-calorie (for energy) and easily available foods.
The Environment of Evolutionary Adaptation
- EEA refers to the environment in which a species first evolved.
- The adaptive problems faced by our ancestors in the EEA would have shaped early food preferences.
- For most of human history, human beings would have lived in hunter-gathering societies, which would have led to a preference for high-calorie (for energy) and easily available foods.
- Preference for fatty foods was adaptive because harsh conditions in the EEA meant that for early humans energy resources were vital to stay alive.
- Early humans evolved a preference for foods that were particularly rich in calories (fatty/sweet foods)
- These preferences for calorie rich foods persist among modern humans, despite the fact that such foods are not particularly nutritious.
PREFERENCE FOR MEAT - GOOD FOR BRAIN GROWTH
- A meat diet was full of densely packed nutrients and therefore provided a catalyst for the growth of the brain.
- As a result, humans were able to evolve into the active intelligent species they became.
- By supplying all the essential amino acids, minerals and nutrients needed to stay active and alive, this allowed early humans to supplement their diet with widely available, but less nutritious, plant-based foods
Taste aversion was first discovered by farmers trying to rid themselves of Rats. They found it was difficult to kill the rats by using poisoned baits because rats would only take a small amount of any new food, and if became ill would rapidly learn to avoid it. T.A was first demonstrated by GARCIA ET AL. Rats, made ill through radiation after eating saccharin developed an aversion to it because they formed an association between the illness and the taste of the saccharin.
ADAPTIVE ADVANTAGES
Taste aversion would have helped our distant ancestors to survive, because if they survive after ingestion poison than they could learn to avoid that food in the future. Once learned, taste aversions are difficult to shift, an adaption that would have helped survival.
THE ‘MEDICINE EFFECT’- the medicine effect describes a tendency for individuals to develop a preference for any food eaten just before recovery from an illness, which then becomes associated with feeling better
PREFERENCE FOR MEAT
Milton 2008 - Claims that without animals it is unlikely that we would have evolved into the intelligent creatures that we are today. This is because there simply would not be enough nutrition in a vegetarian diet.
- EARLY HUMANS - CORDAIN ET AL claimed that early humans are more likely to have found most of their calories in sources other than saturated animal fats.
- HOWEVER, evidence (Abrams’) has shown that all societies show a preference for animal fats, suggesting that this is a universal evolved preference. It is also unlikely that early humans could have found sufficient calories for an active lifestyle from a veg diet.
- IDA - CULTURAL FACTORS are important in food preferences. It is likely that many food preferences (e.g. spicy foods) developed because of cultural tastes and preferences. HOWEVER, although cultural differences do exist, they are usually a fine-turning of evolved food preferences that are found in all cultures.
TASTE AVERSION
TASTE AVERSION CAN BE EXPLAINED by biological preparedness. Differential learning abilities in different species has the ability to learn certain associations more easily than others; particularly associations that help them survive.
IDA – REAL WORLD APPLICATION - Research on the origins of taste aversion has been used to help understand the food avoidance that often occurs during chemotherapy in the treatment of cancer. This claim was supported in a study by BERNSTEIN & WEBSTER, who gave patients a novel-tasting ice cream prior to their chemotherapy and the patients subsequently developed an aversion to that ice cream. This has led to hospitals giving patients both a novel and a familiar food prior to their chemotherapy. Aversion then forms to the novel (i.e. unfamiliar) food and not to the familiar food. This is consistent with our evolved avoidance of novel foodstuffs (neophobia), which is consistent with our survival.