Neural Mechanisms in Aggression

Limbic system - Collective network of structures within the brain, thought to be closely involved in regulating emotional behaviour such as aggression.

  • Reactivity of the limbic system in response to the stimuli, predicts aggressive behaviour (Papez and Maclean).
  • Amygdala plays key role in how we assess and respond to environmental threats.
  • Gospic et al (2011) conducted fMRI scans on ppts in lab based game that provoked aggression.
  • Ultimatum Game: Proposer offers to split money in a certain way with Responder. If Responder accepts; money is split as proposed. If Responder rejects; both receive nothing.
  • Scans showed aggressive behaviours (rejected offer) were associated with fast and heightened response by the amygdala. 
  • Benzodiazepine reduces arousal of the ANS so when taken before the game, this halved the number of aggressive reactions (less rejections) and decreased amygdala activity.
  • The reactivity of the aymgdala therefore proves to be an important predictor of aggressive behaviours enforcing strong evidence of an association between reactive aggression and amygdala activity.
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Neural Mechanisms in Aggression

SerotoninA neurotransmitter, involved in the communications of impulses between neurons.

  • Contributes to feelings of happiness and well being, affects sleep and apetite.
  • Inhibitory effect on the brain.
  • Normal levels of serotonin in the orbitofrontal cortex are associated with greater behavioural self control.
  • Low levels of serotonin disturbs this mechanism results in reduced self control and increased impulsive behaviour (aggression)
  • Virkkunen et al (1994) compared levels of a breakdown product of serotonin (5-HIAA) within the cerebrospinal fluid of violent impulsives and violent non impulsive offenders.
  • Showed much lower levels within impulsive offenders, they suffered from sleep irregularities.
  • This is significant as serotonin regulates sleep patterns. therefore disturbance of this pattern implies that theres also some disruption of serotonin functioning.
  • This therefore supports the role of serotonin in reactive aggression.
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Hormonal Mechanisms in Aggression

Testosterone - 

  • a male sex homone (androgen) produced mainly in the male testes, responsible for the development of masculine features.
  • Dolan et al (2001) studied prison population to see the role of testoserone in aggression.
  • Found positive correlation between testosterone levels and aggressive behaviours within the 60 violent offenders in UK hospitals with maximum secuirity, most suffered from psychopathy.
  • Giammanco et al (2005) Animal studies, demonstrated experimental increase in testosterone is related to aggressive behaviour in several species. 
  • Castration studies showed decrease in testosterone leads to reduction in aggression.
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P - One -ve is the limbic system explanation excludes the role of other brain structures

E - For instance, Coccoro et al showed that activity in the orbitofrontal cortex is reduced in patients with disorders that feature aggression.

E - This shows that the amygdala operates in tandem with the OFC to maintain self control and inhibit aggression.

L - This therefore suggests that the regulation of aggression cannot be explained solely by the limbic system, suggesting that aggression is far more complex

P - One +ve is that there is supporting evidence for the role of serotonin.

E - For instance, Berman et al found ppts who were given a serotonin enhancing drug called paroxetine gave fewer and less intense electric shocks to a confederate than the people in the placebo group. Ppts took part in a lab based game where various intensity shocks were given and received in response to social provocation.

E - This shows that drugs that increase levels of serotonin activity, reduce levels of aggressive behaviour.

L - This therefore provides evidence of a link between serotonin function and aggression.

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P - A -ve of the role of testosterone is that evidence in humans is mixed

E - For instance, Carre and Mehtas dual hormone hypothesis state that high cortisal blocks testosterones influence on aggressive behaviour therefore high testosterone leads to aggression only when cortisal is low. 

E - This shows that there are other hormones other than testosterone which are significantly involved in aggression.

L - Therefore, the combined activity of testosterone and cortisal may be a better predictor of human agrgression than testosterone alone.

- A -ve is that research into both neural and hormonal influences on aggression is correlational.

E - For instance, studies with humans to experimentally maniuplate brain structures and hormones are limited due to ethical reasons and animal studies raise issues of generalisability to human aggression.

E - When two variables are correlated, there are risks of oversymlifying the true mechanisms involved as other factors that have possible influence may be overlooked

L - This therefore means that the neural and hormonal regulation of aggression is almost certainly more complex than our current understanding suggests.

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Genetic Factors in Aggression


  • MZ twins share 100% of genes whereas DZ twins share 50% of genes. Thus we expect greater similarities in aggressive behaviours within MZ twins if aggression is mostly genetic.
  • Coccaro et al (1997) studied adult male MZ and DZ twins. For direct physical aggression, concordance rates for MZ twins was 50% and for DZ twins, it was 28%.
  • For verbal agression, the concordance rate for MZ twins were 28% and for DZ twins, 7%.


  • Similarities in aggressive behaviour between an adopted child and biological parents suggest genetic influences are operationg; but similarities with adopted parents suggest environmental factors.
  • Rhee and Waldman (2002) carried out a meta analysis of adoption studies for aggressive behaviour and anti social behaviour and found that genetic influeces accounted for 41% of the variance within aggression.
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Genetic Factors in Aggression

The MAOA Gene - Monamine Oxidase A

  • This gene is responsible for the activity of the enzyme MAOA in the brain, it cleans after neurotransmitters after nerve impulses have been transmitted between neurons by breaking down the neurotransmitter such as serotonin into smaller chemicals such as 5-HIAA to be either recycled or excreted.
  • A disruption to this function of the gene can lead to abnormal activity of the MAOA enzyme which can in turn affect levels of serotonin in the brain.
  • A variant of the MAOA gene is MAOA-L i.e low MAOA activity in parts of the brain which studies have shown to be associated with aggressive behaviour.
  • Brunner et al (1993) studied 28 male members of a dutch family whom were frequently involved in aggressive violent impulsive behaviour e.g. ****, attempted muder.
  • Researchers found that these men had low levels of MAOA and MAOA-L in their brain
  • Stuart et al (2013) studied 97 men involved in inflicting intimate partner violence (IPV).
  • Results show that men who had MAOA-L were the most violent perpetrators of IPV where they inflicted the most serious injuries to their partner. The engaged in greater psychological and physiological aggression.
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Genetic Factors in Aggression

Gene - Environment Interactions (GxE)

  • Genes do not function alone when it comes to influencing aggression.
  • MAOA-L results to adult aggression when combined with early traumatic life events.

Frazzetto et al (2007) found correlation between MAOA-L and high levels of anti-social behaviour in male adults. This was only the case in those who experienced significant childhood trauma within their first 15 years of life.

  • This supports the diathesis stress model.
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P - One -ve of genetic factors in aggression is that theyre difficult to isolate from environmental factors.

E - For instance, McDermott et al showed that ppts with MAOA-L behaved aggressively only when they were provoked during lab based tasks. 

E - This shows that someone who has an aggression - associated gene may not neccessarily behave aggressively if environment is not appropiate.

L - This therefore proposes a challenge in establishing how influential genes are alone in aggressive behaviour.

P - One -ve of the MAOA explanation is that there are multiple genetic influences

E - For instance, with Stuart et al's study, IPV in men was also associated with the serotonin transporter gene (5-HTT). The combination of 5-HTT with MAOA was closely linked with IPV. 

E - This shows the possibility of other genes involved in aggression other than MAOA alone.

L - It is therefore important to consider the fact that multiple genes interact in complex ways which casts significant doubt onto single gene explainations.

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P - A +ve of the MAOA explanation is its support from prosocial behaviour research.

E - For instance, Mertins et al (2011) found males with MAOA-H  to be more cooperative in lab based tasks whereby they made fewer aggressive moves im comparison to ppts who had MAOA-L. 

E - This suggests that ppts with MAOA-H are more prosocial  as MAOA-L is associated with greater aggression.

L - These findings therefore confirm the importance of the MAOA gene in aggressive behaviour.

P - Another +ve of the MAOA explanation is that there is supportive evidence from animal studies.

E - For instance, Godar et al demonstrated a gene deletion technique in mice of the the gene MAOA. These mice had an increase of serotonin in the brain and were hyper-aggressive. When serotonin was blocked off by the drug fluoxetine, the mice reverted to non aggressive behaviour.

E - This shows the impact of low levels of MAOA operating.

L - Such findings therefore suggest that MAOA must have a normal functioning in relation to serotonin to maintain its levels.

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The Ethological Explanation of Aggression

  • It is the explanation that seeks to understand the innate behaviour of animals including humans by studying them in their natural environment.

Adaptive functions of aggression

  • States the function of aggression is adaptive i.e aggression is beneficial to survival because:

1) Reduces competition - Defeated animals is rarely killed and instead are forced into territory eslewhere reducing competition pressure.

2) Establishes dominance heirarchies - Winning dominance allows one to gain special status such as mating rights over females in chimpanzees.

Pettit et al (1988) studied children in play groups and observed how aggression plays a role in some childrens dominance over others. This study highlights the feature of establishing dominance heirarchies. Dominance is an adaptive feature as it brings benefits such as getting your own way and access to resources.

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The Ethological Explanation of Aggression


  • A series of behaviour that is carried out in set order before physical contact of aggression.
  • Lorenz (1966) noticed within his animal observations of fightsthat aggression consisted mainly of ritualistic signalling and rarely became physical.
  • Such sets of behaviour induce one to accept defeat which prevents much damage to take place on the loser.
  • This is adaptive as it prevents a species to die out.

Innate releasing mechanisms (IRM) and  Fixed  action patterns (FAP)

IRM - An internal structure that is activated by an external stimulus which triggers a FAP.

FAP - A specific sequence of behaviours that is triggered by IRM.

Lea (1984) states that FAP are unchanging behavioural sequences that is a universal feature in all species. It follows an inevitable course which cannot be altered before completion. It has 6 main features: [note them down]

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The Ethological Explanation of Aggression


  • Tinbergen (1951) Male sticklebacks are highly territorial during spring mating season where they develop red spot on their under belly. 
  • Procedure: When another male enters their territory, a FAP is initiated. A red spot on the competing males under belly is the stimulus that triggers the IRM which in turn leads to aggressive FAP. 
  • Bergen presented male sticklebacks with a series of wooden models of different shapes
  • Findings: If the model had a red spot on the underbelly, the stickleback would aggressively display and attack it. This was not the case when the model displayed no red spot.
  • The aggressive FAP did not change from one encounter to another , once triggered it always ran its course to completion without any further stimulus.
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  • One -ve is that there are cultural differences in aggressive behaviour

For instance, Nisbett et al found that when white males from southern US were insulted within a research situation, they were more likely to become aggressive  than northern white males. This was factual only in the case for reactive aggression triggered by arguments

Nisbett concluded that the difference was caused by culture, that impulsive aggression was actually a learned social norm.

Therefore it is difficult for the ethological theory whose notions are that aggression is instinctive, to explain how culture is able to override innate influences.

  • One -ve is that there is some evidence against ritualistic aggression.

For instance, Goodall et al observed male chips from one community systematically slaughter the members of another group in a co-ordinated and premedidated fashion.

This took place despite the victims offering signals of appeasement and defencelessness, this did not inhibit the aggression of the attacking chimpanzees as predicted by the ethological explanation.

Goodalls observation therefore challenge the ethological explanation that aggression has evolved into a self limiting and relatively physically harmless ritual.

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  • One +v is that there is some supporting evidence.

For instance, Brunner et all found that MAOA-L is closely associated with aggressive behaviour in humans, suggesting an innate biological basis.

There is also evidence for IRMs for aggression in the brain - activity in the limbic system triggers aggressive behaviour in humans and other animals.

This therefore increases validity of the ethological explanation (which argues that aggression is genetically determined) by supportive evidence that demostrates the genetic and physiological basis of aggression.

  • Another -ve is that unjustified generalisations made to human aggression.

For instance, Lorenz didnt study higher levels such as primates and Tinbergen chose not to study the extreme destructive aggression. 

However, both made generalisations from animal aggression to humans such as warfare. Lorenz extrapolated from the behaviour of individual animals to the behaviour of entire countries.

We should therefore be cautious about making such generalisations, especially to a complex behaviour which is the outcome of many interacting influences. 

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Evolutionary Explanations of Human Aggression

  • an account of changes in species over millions of years; characteristics that enhance survival and reproduction are naturally selected


  • Sexual jealousy - a major motivator of male aggressive behaviour
  • Unlike women, men can never be completely sure if the child they fathered are theirs (paternity uncertainty)
  • This is the result of cuckoldry - having to raise offspring that are not his own
  • Investment in offspring that do not share the males genes are seen as a waste of his resources
  • This challenged the survival of their own genes which would contributes to rivals genes to survive.
  • Evolution of the psychological mechanisms have led to an increased anti-cuckoldry behaviour in males as they were usually reproductively successful.
  • For instance, sexual jealousy is more strongly experienced in males than females.
  • Men then employ strategies (adaptive in past) to retain their partners and prevent them from straying.
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Evolutionary Explanations of Human Aggression


Wilson and Daly (1996) identified a couple which invloves aggression and physical violence.

  • Direct guarding - Males vigilance over partners behaviour 
  • Negative Inducements - Issuing threats of dire consequences

Also found that women who reported mate retention strategies in their partners were 2x more likely to have experienced physical violence from their partners.

73% of those women required medical attention and 53% said they feared for their lives.

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Evolutionary Explanations of Human Aggression


  • Shackelford (2005) studied IPV in heterosexual couples
  • Procedure: 107 married couples (<1year) completed different questionnairesMen were assessed on mate retention behaviours in various categories e.g. direct guarding. The women were measured on the extent of their partners violence in their relationships.
  • Findings: Strong +ve correlation between mens report (mate retention behaviour) and their partners report (on partners physical violence)
  • Men who used direct guarding or negative inducements were more likely to use physical violence against their partners. 
  • Retention behaviours reliably predict husbands' use of violence against their wives.
  • (Can be used as AO3)

This study is research support as it demonstrates that mate retention strategies are associated with sexual jealousy and aggression. Study shows strategies such as ... are overwhelmingly  used by males, against both females and other males. This indicates a clear link between greater risk of infidelity and cuckoldry and aggression. This supports predictions derived from the evolutionary explanation concerning the adaptive value of aggression.

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Evolutionary Explanations of Human Aggression


  • Bullying = Power imbalance. Stronger individual uses aggression repeatedly against a weaker person.
  • Maladaptive behaviour, e.g. due to poor social skills or childhood abuse.
  • But evolutionary ancestors may have used it as an adaptive strategy to increase chances of survival by promoting their own health and creating reproduction  opportunities.
  • Volk et al suggests that in men, bullying ensures access to females and reduces threats from males. Bullying in men suggests dominance, strength and acquisition of research, such characteristics deliver ideal combination of access to more females and minimal threat from competing males. Thus, aggressive bullying was naturally selected because these males would have reproductive success.
  • Female bullying - takes place within a relationship and is a method of contolling a partner.
  • Bullying in women helps secure partners fidelity, meaning the partner continues to provide resources for future offspring.
  • Such behaviour is naturally selected as it enhanced womens reproductive success
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  • One +ve is that the evolutionary explanantion explains gender differences.

For instance, Campbell (1999) argues that aggression in females risks the survival of their offspring so a more adaptive strategy is to use verbal aggression to retain a partner who provides resources.

Males engage more often than females in aggressive acts, espcially physical aggression, depicting a gender difference.

Therefore, the fact that the evolutionary expalnation can explain such gender differences in aggression increases validity of this kind of approach.

  • Another +ve is that there is real life applications. 

For instance, Rigby et al reveiwed several established anti bullying interventions. Despite the presence of such interventions, bullying is still prevalent. 

Interventions fail to recognise that bullies bully because they gain advantages, thus wouldnt make sense for them to voluntarily give up the power they have over others without some form of compensation. 

An evolutionary comprehnsion of bullying as an adaptive behaviour can help us to devise effective anti bullying interventions, to increase the costs of bullying and the rewards of prosocial alternatives. 

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  • One -ve is that there is cultural differences.

For instance, the KungSan people discourage aggression and those who use it lose status and reputation. Alternatively, the Yanomamo people use aggression to gain status in their structured society. 

However, the evolutionary explanation predicts aggression is present in all cultures because it is used everywhere to increase survival chances through greater reproductive success.

Therefore the contradictory information presented suggests aggression is not universal because the KungSan and Yanomamo people demonstrate differences to such experiences. 

  • Another -ve is of the methodological issues within the research evidence.

It is extremely difficult to test a hypotheses about the evolution of behaviours to solve problems of adaption in our past thus research is correlational.

However, a strong correlation cannot allow us to conclude that evolutionary factors cause aggression. 

This therefore makes it very difficult to establish how valid an evolutionary explanation of aggression is.

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Social Psychological Explanations FAH

  • Opposite of the intentions from Biological explanations
  • Theories that argue aggression is the result of an interaction between an individuals characteristics and features of  situation in which the behaviour occurs.

Fustration - Aggression Hypothesis - argues that anger, hostility and even violence are always the outcome when we are prevented from achieving out goals i.e. fustrated.

  • Dollard et al (1939) - fustration leads to aggression; aggression is result of fustration.
  • Based on psychodynamic concept of cartharsis. Aggression = Psychological drive.
  • Fustration is experienced if attempt to achieve a goal is blocked by external factor. Fustration creates aggressive drive = Agressive behaviour e.g. physical violence.
  • This is cartartic as aggression created by fustration is satisfied. Feeling better for having gotten it 'off our chest'
  • Hypothesis acknowledges anger can be deflected from source of fustration due to 3 reasons:
  • Cause of fustration is abstract
  • Cause is too powerful and risk punishment if agressing
  • Cause is unavailable at the time
  • Aggression is displaced onto alternatives i.e. not abstract, weaker and available e.g. younger sibling :(
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Social Psychological Explanations FAH


Russel Green (1968) - to investigate the effects of fustration on agression

  • Procedure: Male uni students completing a jigsaw puzzle, within that period, levels of fustration were manipulated in 1 of 3 ways:
  • Puzzle was impossible to solve for some ppts (1)
  • Ran out of time because confederate kept interfering (2)
  • Insulted by the confederate student (3)
  • Subsequently, ppts had to give (fake) electric shocks to the confederate whenever they made a mistake on another task.
  • Findings: All 3 groups selected more intense shocks than non fustrated control group.
  • Ppts of (3) gave stronngest shocks on average, then (2), then (1)
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Social Psychological Explanations FAH

The Role of Environmental Cues

  • Berkowitz et al states the presence of aggressive cues in the environment make acting upon aggression more likely. Thus, cues are an additional element of the fustration - aggression hypothesis.
  • Procedure: Arranged student ppts to be given electric shocks by student confederate in lab situation in which created anger and fustration. 
  • Ppts then had chance to turn tables to give electric shocks to the confederate.
  • Findings: Once students became fustrated in lab task, were more l ikely to shocks when they could see a weapon next to them 6.07
  • No guns = average shock given was significantly fewer 4.67
  • Weapon effect shows fustration creates a readiness for aggression, aggressive cues make it more likey that aggression will happen.
  • This effect supports Berkowitz contention that presence of aggressive environmental cues stimulates aggression. 
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P - A +ve of this explanation is that it has useful real life applications.

E - For instance, Berkowitz idea that 'the trigger can pull the finger' has featured in the gun control debate in the US.

E - There are states that allow 'open carry', whereby a gun does not need to be concealed. However, presence of a weapon can act as a cue to aggression making the use of guns more likely.

L - This therefore enforces that research into weapons effect may reduce gun related violence by showing that aggressive cues should be removed from the environment- ultimatley saving lives.

P - A -ve is that there is evidence that aggression is not carthartic.

E - For instance, Bushman (2002) found participants who vented their by hitting a punchbag became more angry and aggressive rather than less.

E - Many therapists claim venting to reduce anger is like putting out fire with petrol. 

L - This therefore casts doubt on the validity of the central assumptions of the F-A hypothesis.

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P - A +ve is that the original hypothesis was reformulated to fit the evidence.

E - For instance, Berkowitz argued that fustration is just one of many aversive stimuli that create negative feelings as fustration doesnt always lead to aggression and aggression can occur without fustration. 

E -  Aggression is triggered by negative feelings generally rather than by fustrations specifically, The outcome of fustration can be a range of responses; only one is aggression.

L - This is therefore a strength because it highlights the flexibility of the hypothesis and is how science operates, a theory is adaptive when evidence comes along that it cannot explain. 

  • A -ve is the effects of justified and unjustified aggression

For instance, Dill and Anderson (1995) showed ppts a paper folding task but fustrated them by making it difficult to follow, either because the experimentor wanted to meet his girlfriend (unjustified) or because his boss told him to hurry up (justified).

Ppts who experienced unjustified fustration produced most aggression (negative judgements of experimentor). Justified fustration produced less agression but more than the control group who had an absence of fustration.

Results show that some forms of aggression can create more aggression than others, this is therefore a serious challenge to the validity of the original hypothesis.

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Social Psychological Explanations SLT

SLT Applied to Human Aggression

  • Banduras STL recognises that aggression can be learned directly via operant conditioning (+ve, -ve reinforcement, punishment) E.g. child who angrily snatches toy away, learns this way brings rewards i.e. direct +ve reinforcement.
  • Also learning indirectly via
  • Observational learning - child observes models being aggressive and works how that behaviour is performed.
  • Then child observes potential consequences of aggressive behaviour. If rewarded, comprehends this behavior can be effective.
  • Known as Vicarious reinforcement- makes more likely that the child will imitate the models aggressive behaviour.
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Social Psychological Explanations SLT

Cognitive Control of Aggressive Behaviour

4 cognitive conditions are needed for observational learning to take place:

  • Attention
  • Retention
  • Reproduction
  • Motivation
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Social Psychological Explanations SLT


  • The extent to which we believe our actions will achieve a desired goal.
  • A childs confidence in their ability to be aggressive grows as they learn that aggression can bring rewards
  • Childs sense of self efficacy develops with each successful outcome.
  • They become confident about the fact that their aggression has been effective in the past so it will continue to be so in the future.
  • They learn aggression works and that theyre good at it.
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Social Psychological Explanations SLT

Rsearch into Social Learning of Aggression

  • Bandura et al (1961) Bobo doll study
  • Procedure: Young children individually observed an adult model playing with toys that included the Bobo doll.
  • One group of children observed the model behaving aggressivley towards the doll (physically and verbally).
  • They were then taken to another room where there was a Bobo Doll and toys the model had used
  • Findings: Children from that group imitated the behaviour they observed, the closeness of imitation was significant as there was a direct copy e.g. using specific objects and verbal phrases
  • Children in the non aggressive model condition showed almost no aggression later.
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  • P - One +ve is that there is supportive research evidence.

For instance, Poulin et al (2000) found that most aggressive boys aged 9-12 years formed relationships with other aggressive boys- such cliques are 'training grounds' for antisocial behaviour.

This means that they were frequently exposed to models of physical aggression and to its reinforcing consequences such as gaining rewarding approval.

This therefore shows that aggression increases accuracy in the conditions predicted by SLT.

  • P - One -ve is that SLT cannot explain all forms of aggression.

For instance, children who utilise proactive aggression have higher levels of self efficacy, they are confident so they use aggression to achieve their goals. This type of behaviour is well explained bt the SLT.

However, children who use reactive aggression act to attain retribution only in the heat of moment.

Therefore such behaviour of reactive aggression is less explicable from a SLT perspective and is better explained by an alternative theory such as from Berkowitz theory of negative affect.

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P - Another +ve is that it has useful real life applications.

For instance, Eron et al (2013) argues that media portrayals of aggressive behaviour can be powerful influences on a childs acquisition of aggression.

This is especially true if a media character is rewarded for being aggressive ( vicarious reinforcement).

Therefore such effects support the predictions of SLT and can be applied to reducing aggressive behaviour by providing non aggressive models in the media.

P- A -ve is SLT has difficulty explaining cultural differences in aggression.

For insance, in some cultures like the people of kung san, their social norms do not encourage aggression so aggressive models are unavailable to young children and so vicarious reinforcment is rare. However this isnt to say that they do not behave aggressively at all.

This shows that different cultures have different norms about which behaviours should be reinforced.

This therefore suggests there is more to aggressive behaviour than social learning and so other approaches may have more valid explanation of this cultural variance.

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Social Psychological Explanations De-individuation

De-individuation: Psychological state in which an individual loses their personal identity and takes on the identity of the social group when e.g. in a crowd or wearing a uniform. The result may be to free the individual from the constraints of social norms. [LeBon(1895)]

  • Crowd behaviour - Our behaviour is constrained by social norms as we are easily identified by others. We live in a society where most of aggressive behaviour is discouraged. However, when we are part of a crowd, we lose restraint and behave in ways wouldnt otherwise. Sense of self identity and responsibility of our behaviour is lost and attain greater disregard for norms and laws. Responsibility becomes shared throughout the crowd so we experience less personal guilt when harmful aggression is directed at others.
  • Di-individuation leading to aggression - Zimbardo (1969) distinguished between individuated and de-individuated behaviour.
  • Individuated state; behaviour generally rational and normative i.e. conforms to social norms. De-individuated state; emotional, impulsive, irrational, anti-normative, disinhibited, lose self-awareness, stop monitoring and regulating behaviour, ignore social norms, 'live in the moment' Conditions of such state which promote aggressive behaviour include drugs, alchohol, masks and disquises. Major factor is anonimity where there is less fear of retribution due to small and unidentifiable part of faceless crowd. The bigger the crowd; the more anonymous we are. Anonymity provides fewer opportunities for others to judge us negatively.
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Social Psychological Explanations De-individuation

  • The role of self-awareness - the experience of de-individuation as part of a faceless crowd creates greater liklihood of aggression. 
  • Rogers et al states not due to anonymity directly, but to consequences anonymity. 
  • 2 types of self- awareness:
  • Private self-awareness; how we pay attention to our own feelings and behaviour, reduced when part of a crowd. Attention becomes focused outwardly to the events around us, so we pay less attention to our own beliefs and feelings. We are less self-critical, less thoughtful and evaluative which all foster he de individuated state
  • Public self awareness; how much we care about what other people think of our behaviour, also reduced within crowds. Realisation occurs that we're just one individual amongst many; we're anonymous and behaviour is less likely to be judged by others. No longer care about how others see us so we become less accountable for our agressive actions.
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Social Psychological Explanations De-individuation

KEY STUDY: Student De-Individuation

  • Dodd (1985) 
  • Procedure: Asked 229 psychology students,'If you could do anything humanly possible with complete assurance that you would not be held responsible, what would you do?' Students were aware their responses were anonymous. Three independant raters who didnt know hypothesis decided which categories of antisocial behaviour the responses belonged to.
  • Findings: 36% of the responses involved some form of antisocial behaviour. 26% were actual criminal acts. Most common was to rob a bank.  9% of responses were prosocial behaviours (helping people). Very few opted for ****, murder or assasination of president.
  • This study demonstrates a link between anonymity, de-individuation and aggressive behaviour. 
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One +ve is that there is supportive research evidence.

For instance, Douglas et al (2001) looked at aggressive online behaviour in chatrooms and the uses of instant messaging. 

They found a strong correlation between anonymity and 'flaming', (posting hostile messages). the most aggressive messages were sent by those who hid their identities.

This therefore suggests a link between anonymity and de-individuation and aggressive behaviour in a context that has greater relevance today.

One -ve is that there is some contradictory evidence. 

For instance, Gergen et al put strangers in a pitch dark room and told them to do whatever they wanted - they soon strted kissing and touching each other.

Study was repeated but ppts were told they would be face to face to each other - kissing and touching was reduced.

This therefore shows that despite the guarantee of anonymity creating the conditions for de-individuation, aggressive behaviour was not an outcome of this study.

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  • A -ve is that de-individuation does not inevitably lead to aggression.

For instance, Downing et al (1979) conducted a study where female ppts gave fake shocks to a confederate either wearing masks, dressed as nurses or wearing their own clothes.

Masked ppts gave more intense shocks and the 'nurses' gave fewer at lower levels. They were also more compassionate towards victims, this is in line with the prosocial role associated with a nurses uniform. 

This therefore suggests that both aggression and prosocial behvaviour are potential outcomes of de-individuation (not just aggression). Normative cues in the situation determine which is most likely to occur. 

  • A +ve is that it has useful real life applications. 

For instance, de-individuation theory can help is to understand aggressive behaviour in online gaming services.

Such services can promote psychological state of de-individuation, there is a reduction of personal identity and game playing in such an evironment is arousing and immersive. There is also the presence of a crowd in the form of a potentially world wide audience.

This real life application therefore confirms the relevance of de-individuation concepts for aggression as anonymity enables conditions of de-individuation and reduction in self awareness.

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Institutional Aggression: Prison Context

Instutional Aggression - Aggressive or violent behaviour that takes place within the social context of a prison or other formal organised social settings, results from characteristics of prisoners. 

Dispositional Explanations - Locate the cause of aggressive behaviour within the individual (personality)

  • Importation model - Irwin and Cressey (1962) argued that inmates import into prisons a subculture typical of criminality including beliefs, attitutude and personal characteristics.
  • The willingness of inmates to use violene inside prison to settle dispites reflects their lives  before there were imprisoned.
  • Inamtes import such behaviour to negotiate their way through the unfamiliar prison environment in which existing inmates use aggression to establish power, status and access to resources - convict subculture.
  • ∴ aggression is the product of individual characteristics of inmates and not of the prison environment. Inmates who are predisposed to using violence would be more likely to do so in any setting, and were experienced in doing so outside prison.
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Institutional Aggression: Prison Context

Situational Explanation - identifies the causes of behaviour as existing within prison environment, may include other people. Emphasise importance of social context.

  • The deprivation model - Clemmer (1958) Harsh prison conditions cause stress for inmates who cope by behaving agressively. Conditions are of deprived of freedom, independance, and heterosexual intimacy ect. Deprivation of material goods increases competition amongst inmates to acquire them thus corresponding increase in agression.
  • Aggression also influenced by the nature of prison regime which are unpredictable ad use lock up systems to control behaviour. This creates fustration and reduces acess to good e.g. television.
  •  This is a recipe for aggression which becomes an adaptive solution to the problem of deprivation.


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Institutional Aggression: Prison Context

Research into the deprivation model - Steiner (2009)

  • Procedure: Investigated the factors that predicted inmate aggression inmate aggression in 512 prisons US.
  • Findings: Inmate-on-inmate violence was most common in prisons where there were higher proportions of female staffs, African-american and hispanic inmates. These are prison level factors because they are independent of individual charactrisics of prisoners, they reliably predicted aggressive behaviour in line with the deprivation model.
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  • A +ve of the importation model is its research support. 

For instance, Camp et al (2005) placed half of their male inmate ppts in low security prisons and the other half in a much higher level of security prison.

Findings were that there was no significant difference in aggressive misconduct between the two groups, features of the prison environment were less important pridictors of aggressive behaviour than characteristics of inmates.

This is therefore strong evidence in support of the dispositional explanation especially because   random allocation was utilised to inamtes to prisons of different levels of security; inhibits bias.

  • A -ve of the importation model is an alternative may be better.

For instance, Dilulio (1991) claims the importation model is inadequate to explain institutional aggression because it ignores the roles of prison officials and factors linked to running prisons.

He suggests an administrative control model (ACM) which states that poorly managed prisons are more likely to experience most serious forms of inmate violence. 

This therefore decreases the validity of dispositional explanation as according to the ACM, these factors are considered more influential in determining aggression than the inmates disposition.

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  • A +ve of the deprivation model is that there is research support.

For instance, Cunningham et al analysed inmate homocides in Texas prisons and found motivations for the behaviours linked to some of the deprivations identified by Clemmer. 

Although individual level factors can be predictors of aggression that are independant of prison environment, this reseach shows that some situational variables can also be highly influential.

This therefore supports the validity of a situational explanation as these factors were predicted according to the deprivation model in making aggression more likely. 

  • A -ve of the deprivation model is that there is also contradictory research suppport.

For instance, Hensley et al studied inmates of prisons allowing conjugal visits i.e to have sex. Found no link between involvement in these visits  and reduced aggressive behaviour.

This goes against what the deprivation model predicts, that a lack of freedom and heterosexual contact leads to high levels of aggression; Hensleys reseach does not support this.

This therefore shows situaltional facotrs do not affect prison violence, decreasing the validity of the deprivation model. 

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Media Influences: Computer effects

The effects of computer games on aggression derived by either 3 methodologies .

  • Experimental studies - Bartholow and Anderson (2002) - Ppts played either violent or non violent computer game for 10 minutes . Then carried out the TCRTT, measure of aggression in which ppts delivered blast of white noise at chosen volume to punish opponent. Those who played the violent game selected significantly higher noise levels with non violent players.

+ Allows us to establish a causal link between media aggression and aggressive behaviour.

- Studies that measure aggression in lab situations are often accused of being artificial and unrealistic such as TCRTT which measures how much loud noise is selected. But then it would be unethical to allow real forms of aggression to take place in research study e.g To let people hit each other. So researcher have no choice but to be creative in devising ways to measure aggression

-Another reason aggression measures in lab may be unrealistic is that they do not involve any fear of retaliation. Unlike the real world, ppts often recieves implied permission to be 'safely' aggressive.

-Deceases validity of experimental studies and on  link between violence media and aggression

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Media Influences: Computer effects

  • Correlational Studies - DeLisi (2013) - studied 227 young offenders with history of serious aggressive behaviours. Structured Interviews used to gather data on aggression and violent computer game playing. Found their aggressive behaviour was positively correlated with how often they played violent video games and how much they enjoyed them. Link is well established, computers should be considered a risk factor. 

+Allow us to investigate realistic forms of aggression including violent crime. 

- There is an inability to draw a cause and effect conclusion as no variables are controlled or manipulated, there is also no random allocation of participants to violent or non violent media conditions. 

-A positive correlation between violent computer games and aggression can be explained by socialisation (violent games cause people to be aggressive) or selection (people who are already aggressive choose violent games). 

Therefore the direction of causality cannot be settled by correlational studies as findings do not help us choose between two competing hypothesis which leaves open the question of how exactly how computer games influence aggression. 

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Media Influences: Computer effects

  • Longitudinal Studies - Robertson (2013) - Studied 1037 NZ people1972-1973 measuring their TV veiwing hours at regular intervals up to age of 26 years. Time spent watching was a reliable predictor of aggressive behaviour in adulthood (convictions)  and diagnosis of anti personality behaviour. Important factor i influencing aggression may be down to amount of tv watched rather than its naure of content. 

This methodology is used to investigate changes in aggressive bhaviour over time, therefore the dynamic nature of media influences in the long term can be studied. This approach also veiws people as active recipients rather than passive which is a more realistic view in how people interact with media. 

- Such studies are vulnerable to effects of confounding variables. Many other sources of aggression also interact with media influences over time, such as role models (friends or family). Therefore it becomes difficult to seperate them all and assess their contributions to aggressive behaviour. 

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Media Influences: Computer effects

  • Meta-Analysis - Anderson et al (2010) - of 136 studies including all 3 methodological  research.

Found exposure to violent computer games was associated with increases in aggressive behaviours,thoughts and feelings. True for both males and females in individualist and collectivists cultures.

The higher qualilty studies in the analysis showed an even greater significant effects. The rsearchers claim that the effect of violent game playing on aggressive behaviour is greater than the effect second hand smoke has on cancer.

Also, the analysis showed  no indication that publication bias influenced the results.


- Publication bias; there is known tendancy to publish only statistically significant results. It creates the false impression that the effects of violent media on aggression are greater than they actually are.

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Media Influences: Part 2

Looking at 3 factors which may account for the research that we explored previously.

  • Desensitisation - repeated exposure to violence reduces normal levels of physiological and psychologicalarousal associated with anxiety, making aggressive behaviour more likely.
  • When we witness aggression we experience arousal associated with the sympathetic nervous system e.g. increased heart rate, blood pressure, sweat activity.
  • But when repeatedly view aggression via media, they become habituated and physiological effects are reduced (desensitisation) - a stimulus that is usually aversive has a lesser impact, resulting in a reduction of anxiety and physiological arousal on repeated veiwing.
  • Repeated exposure to violent media promotes the belief that agression as a method of resolving conflict is socially acceptable, therefore negative attitudes towards violence weaken, less empathy is felt for victims
  • Weisz and Earls(1995) Lab study highlighting desensitisation effects. Showed ppts the film straw dogs containing a scene of violent [email protected] then a [email protected] trial. Male veiwers of the film showed greater acceptance of sexual aggression and expressed less sympathy towards the **** victims in trial and so less likely to find defendant guilty. Compared to control group who didnt watch violent sexual film. Effect not seen in female participants.
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Research support for desensitisation

Krahe et al (2011) showed participants violent and non violent film clips while measuring physiological arousal using skin conductance.  

Participants who were habitual veiwers of violent media showed lower levels of arousal as they watched the violent film clips.

They also reported higher levels of pleasant arousal and lower levels of anxious arousal. Lower arousal was correlated with unprovoked (proactive) aggression in a noise blast task.

These findings confirm theories based on desensitisation. The lower arousal in violent media users reflects desensitisation to the effects of violence and even a greater willingness to be aggressive.

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Media Influences: Disinhibition

Disinhibition - Normal social constraints against certain behaviours can be weakened by environmental triggers. These behaviours then appear temporarily socially acceptable and therefore more likely.

  • Most people believe violence and aggression are antisocial and so there are powerful social and psychological inhibition against using aggression to resolve internall conflicts. Learnt via SLT
  • These restraints are loosened after exposure to violent media where aggression is depicted  as normative and socially sanctioned - minimise the effects of violence on its victims and suggest that it is justified. 
  • Video games to show violence being rewarded or have minimised consequences isnt unusual, this creates new social norm in the veiwer.
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Research support for disinhibition

Berkowitz and Alioto (1973) found ppts who saw a film depicting aggression as vengence gave more electric shocks of a longer duration to a confederate. This suggests that media violence may disinhibit aggressive behaviour when it is presented as justified

This is because vengeance is a powerful justification for violence and justified violence is more likely to be seen as socially acceptable.

This adds validity to the disinhibition concept because it demonstrates the link between removal of social constraints and subsequent aggressive behaviour atleast in the case of justified aggression.

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Media Influences: Cognitive Priming

Cognitive priming - Violent images provide us a ready made scripts about aggression which are stored in memory and triggered when we perceive aggressive cues in a situation.

  • Repeated veiwing of aggressive media can provide us with a 'script' about how violent situations may play out 
  • Huesmann (1998) argues this script is stored in memory, so we become 'ready' (primed) to be aggressive. This is an automatic process; direct out behaviour without us being aware. 
  • Sript is triggered when we encounter cues in a situation that we percieve as aggressive.
  • Fischer et al (2006) investigated song lyrics as a form of media violence. Male ppts listened to songs fting agressively derogatory lyrics about women. 
  • Compared with when they listened to neutral lyrics, ppts later recalled more negative qualities about women and behaved more aggressively towards a female confederate. 
  • Similiar results with females  and men hating lyrics.
  • Illustrates  priming of aggressive scripts in memory.
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Practical Application of Cognitive Priming

P - A strength of cognitive priming is useful practical applications in the sense that there are life saving benefits to understanding its infleunce in real life situation

E - For instance, Anderson et al states someone who habitually watches violent media accesses stored aggresive scripts more readily so theyre more likely  to interpret cues as aggressive and resort to a violent solution and fail to consider alternatives.

E - Understanding  how cognitive priming influences aggressioncan potentially save lives, whether situations break into violence depends on how individuals interpret cues which depends on scripts stored in memory.

L - This therefore raises the possibility that effective interventions could reduce aggressive behaviour by challenging hostile cognitive scripts and encouraging habitual violent media users to consider alternatives e.g. humour or negotiation.

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