aggression

name 3 genetic explanations for aggression

1. twin studies

2. adoption studies

3. warrior gene/maoa gene

explain twin studies

• have been done to explain link between genes and aggression

• mz and dz have same environment but mz shares more of same genes

• if aggression behaviour is more similar in mz than dz then it should be due to genes

• found 50% concordence rate for mz and 19% for dz
  → shows violent behaviour can be attributed to genetics

name a limitation of using twin studies

mz are more likely to be treated similarly than dz as they look the same which might explain higher concordence rate
+ can’t split from environment ethically

explain adoption studies

• 1,400 adoptions in denmark (allows to separate environment and genetics)

• children of violent criminal bio parents (non-criminal adoptive) - 20%

• children of non-violent criminal bio (violent criminal adoptive) - 15%

• both biological and adoptive violent criminal parents - 25%

• evidence for genetic effect and influence from environment, but environment is weaker

name a limitation of using adoption studies

children who are adopted are more likely to be angry and disturbed

aggression may occur as a response to feeling abandoned by bio family

explain warrior gene/maoa gene

• levels of hormones and neurotransmitters genetically determined

• gene responsible for producing MAOA has been associated with aggression

• study on family where all men were violent found they had low variant of MAOA gene and defect on x chromosome was identical

• MAOA gene is more popular in strong war cultures (2/3 have maoa-low, 1/3 in western countries)

• maoa-l ppts have higher levels aggression than maoa-h ppts when provoked
  → seretonin isn’t properly broken down which leads to aggression

name a strength of maoa

supporting evidence

• if maoa-l is associated with high levels of aggression then maoa-h should lead to pro-social behaviour

• research found males with high activity variant were more cooperative in tasks and less aggressive

• shows importance of MAOA in aggressive behaviour

name 3 limitations of MAOA

1. requires interaction with environment
   children with maoa-l shows more anti-social behaviour but only if they had been mistreated as children
   children with maoa-l who weren’t maltreated were a lot less likely to become aggressive
   shows interaction of nature and nurture
   

2. requires interaction with environment
   research found some people with aggressive genes are only aggressive in certain circumstances
   maoa-l ppts behaved aggressively but only when provoked
   exact circumstances need to be considered and so it is hard to know how genes influence
   + done as a lab study so lacks ecological validity
   

3. biological determinism
   if aggression is caused by specific genes/hormones then we would expect everyone to respond the same
   however, people vary with their aggression levels when in the same circumstance as others with these levels, and aren’t as aggressive
   this suggests a degree of choice in aggression, which there wouldn’t be if it was only biological

name 3 neural explanations for aggression

1. limbic system abnormalities

2. seretonin too low

3. testosterone

explain limbic system abnormalities

limbic system: subcortial (below cortex) structures

hypothalamus, hippocampus, thalamus and amygdala

associated with emotional behaviour

amygdala plays key role in reactivity of an organism and how they respond to threats or challenges

reactivity of amygdala is a good predictor or severe and persistent aggression

name 2 strengths of limbic system as an explanation for aggression

1. evidence from case studies
   phineas gage
   iron rod when through the brain and took some of the left frontal lobe

   he experienced drastic personality change- e.g. impulsiveness, irritability and disrespectful

   believed damaged area was responsible for emotion and personality
   
   
   charles whitman

   austin texas university mass murderer
   left note begging for brain to be studied after death
   autopsy shows tumor was pressing on his amygdala
   

2. supporting evidence- gospic
   had ppts play the ’ultimate game’
   proposer would offer to split money with ppt (responder) in a certain way
   if responder accepts, money is split as proposed, but if they didn’t, neither got the money
   used fmris to scan brain
   found that when responder rejected unfair offer (aggressive act), there was a fast and heightened response by the amygdala
   when given drugs to reduce activity, there were fewer rejections and lower activity in amygdala
   → lab study and ecological validity

explain the seretonin being too low

• seretonin is involved in the communication of neurons
  → normally inhibits neural activity

• normal levels of seretonin in orbitiofrontal cortex are linked to good behavioural control

• decreased levels may lead to impulsive behaviour like lack of self control and aggression

• research found lower levels of seretonin makes adults and children more prone to violence

name 2 strengths of seretonin being too low

1. supporting evidence
   took cerebrospinal fluid from violent offenders
   found lower than average seretonin levels
   these offenders with low seretonin levels werre also more likely to commit violent crimes after prison
   works alongside genetics as this influences seretonin production
   

2. supporting evidence
   gave ppts placebo or paroxetine drugs (enhances seretonin activity)
   ppts then took part in a game where shocks were given or received at varying intensities in response to provocation
   ppts in drug group gave fewer shocks than those in the placebo group

explain testosterone

• male sex hormone which influences aggression from young adulthood

• research found that lowering levels of testosterone reduces aggression and raising it increases it in many species

• prisoners who commit violent crimes (unprovoked) have higher levels of testosterone than those who commited non-violent crimes

• teens with higher lecels of testosterone are more prone to delinquency, drug use and reactive responses to being provoked
  

• found FTM taking testosterone became more aggressive and sexual

• and MTF taking testosterone suppressants became less aggressive and sexual

name 4 groups with higher levels of testosterone

• aggressive boys

• violent criminals

• people with criminal records

• military vetreans who went AWOL or got in trouble after service

name 2 constants across cultures regarding testosterone

1. men are more likely to commit violent acts → 85% arrested for violent crimes in USA are men

2. young people are more likely to be aggressive than older people

name 2 strengths of testosterone

1. supporting evidence
   research found if a male mouse is castrated then leves of aggression decrease
   if the mouse then gets testosterone injections, aggression levels start to increase again
   counterpoint: cannot generalise animal behaviour to humans → aggression in humans is a lot more due to context and cognitive influences
   

2. supporting evidence
   60 male offenders in maximum security hospital in uk
   research found a positive correlation between aggressive behaviour and testosterone levels
   → testosterone likely regulates human aggression
   counterpoint: sample may not be representitive beyond violent offenders as they had range of personality disorders like psychopathy

name a limitation of testosterone

1. methodology
   positive correlation studies often have small samples and use self report techniques
   → demand characteristics and social desireability bias
   also usually on offenders so not generalisable
   correlational usually so not possible to conclude that testostrone causes aggression
   not always negative, high levels can be linked to spatial abilities and team cooperation in sport

explain ethological explanations of aggression

• aggression is an instinct which occurs in all members of a species and doesn’t need to be learnt

• innate and genetically determined (mostly)

• ethologists study behaviour in non-human animals and use findings to understand human behaviour (all drawn by same forces of natural selection)

• suggest aggression is adaptive and beneficial for survival since the defeated animal os rarely killed, just forced to establish territory elsewhere and therefore spread out wider
  → discover different resources which reduces competition and aids survival

• aggression also helps create hierarchies (e.g. mating rights)
  → shown in apes, wolves and lions

what is an innate releasing mechanism (IRM)

biological structure or process in brain which is activitated by an external stimulus (sign stimulus)

turns into FAP

what is a fixed action pattern? (FAP)

sequence of stereotyped pre-programmed behaviours triggered by IRM

explain the tinbergen study for ethological explanations (procedure)

• male sticklebacks are highly territorial during mating season → they develop a red spot on their underbelly

• if another male enters territory with the red underbelly, a sequence of highly stereotyped aggressive behaviours and FAP take place

• the sign stimulus (red belly) initiates the innate releasing mechanism

• tinbergen presented sticklebacks with a series of wooden models of different shapes

explain the tinbergen study for ethological explanations (findings)

• regardless of shape, if the model had a red belly the stickleback would aggressively display and attack it

• tinbergen found aggressive displays were unchanging from each encounter

• once triggered, the FAP always ran it's course to completition without any further stimulus

ADD STRENGTHS AND WEAKNESSES FOR ETHOLOGICAL

ADD STRENGTHS AND WEAKNESSES FOR ETHOLOGICAL

explain evolutionary explanations (infidelity)

• evolutionary theory suggests male aggression is linked to infidelity (sexual or emotional)

• creates an issue in men as they can never be certain a child is theirs
  → known as paternity uncertainty which provokes jealousy and therefore aggression when they feel threatened

• men have been guarded against cuckoldry (raising a child that isn’t theirs)
  → seen as waste of effort and resources as you aren’t passing on your genes but instead a rivals

• men would guard against it through aggression to keep a mate

explain research regarding infidelity and aggression

wilson
found several male retention stratergies such as:

1. direct guarding
   over-vigilance of partners behavuour
   → e.g. checking where they are, keeping tabs on them all the time
   

2. negative inducements
   making threats of negative consequences as a result of infidelity
   

this leads to aggressive behaviour

wilson later found women who reported their partner was jealous and didn’t want them to talk to other men were 2x as likely to be victims of domestic abuse
→ 73% required medical intervention due to assualt

suggests aggression is a male retention stratergy

explain bullying and evolution

• when a more powerful individual is aggressive repeatedly to a weaker person

• evolutionary psychologists think it shows the men as stronger so therefore more likely to reproduce
  
  research

• characteristics of a male bully such as dominance and strength are attractive to opposite sex → suggests strength and protection

• behaviour is naturally selected as it wards off rivals and increases reproductive success]

• also suggests women who bully in a relationship do so to control their partner and keep fidelity to ensure resources

name 3 limitations of evolutionary explanations of aggression

1. supporting research- infidelity
   found aggressive behaviour was designed to stop women being unfaithful
   55% battered women said jealousy was why their husband was aggressive
   often only speculative and based on suspicions
   

2. supporting research- infidelity
   studied domestic violence using questionaires
   men completed ‘mate retention inventory’ which assessed how frequently they used these strats
   women completed the ‘spouse influence report’ which measured how violent their partners were
   found strong positive correlation between male retention and reports of physical violence
   

3. practical applications- bullying
   evolutionary explanations guide us about how to make anti-bullying campaigns better
   this can be done by increasing consequences of bullying and rewarding prosocial behaviour, otherwise there’s no reason to stop

name 2 limitations of evolutionary explanations

1. cultural differences
   predicts aggression should be present in all cultures.
   however, some discourage it so much they can lose social status
   e.g. Kung San people are not violent at all due to looking down on it so much
   not universal so unlikely to be evolutionary, maybe too simplistic
   

2. determenistic
   we have control over our behaviour and can choose to work through aggression
   if it was evolution and biological then everyone should act the same way in response to this stimulus but many people don’t.
   some don’t get jealous at all, some use peaceful mate retention tactics, etc.
   if it was evolutionary/biological we’d expect us to all act the same

what is deindividuation?

process of decreased self-assessment when identification of someone is difficult/impossible

individuals feel less responsible and so guilt reduces

crowds, uniform and alcohol influence this → KKK

what does le bon say about deindividuation?

le bon

people are more likely to behave aggressively if they’re in a large or anonymous group → mob mindset

describe individuated behaviour

rational

consistent with social norms

non-acceptable behaviours constrained

described deindividuated behaviour

unrestrained and more primitive

anti-social acts

explain zimbardo and deindiviuation

aim: see effects of deindividuation

procedure: groups of 4 women gave shocks to another student to ‘aid learning’
condition A wore lab coats and hoods to hide face
condition B wore normal clothes with large name tags

findings: deindivuated condition had more electric shocks given and held it down for twice as long

name 4 other examples of deindividuated research

1. stanford prison experiment
   sunglasses and uniform gave anonimity and were unaware they were filmed at night
   prisoners only referred to as numbers
   → more aggressive and conformed to these roles
   

2. northern ireland
   analysed 500 attacks (violent) in northern ireland → 200 in some sort of disguise and these were more violent
   

3. suicide baiting
   suicide leaps had the most suicide baiting when the crowd was large at night and at a distance to the person
   

4. kkk
   found the larger the group, the more savagely they were

name 3 strengths of deindividuation

1. social learning theory
   slt says vicarious reinforcement leads to favourable outcome
   e.g. banduara study, children who saw model be punished weren’t aggressive, but did know (when asked) what the aggressive behaviours were
   people may learn through SLT but fear punishment
   when given chance to not be punished, they act violently
   

2. supporting evidence
   research had psychology students explain how they’d behave if given chance to be anonymous and not be punished
   anonymous responses were rated by independent raters as prosocial, anti social or illegal
   39% anti social / 9% prosocial
   shows link between behaviour and anonymity
   counterpoint: demand characteristics as psychology students
   

3. universal across cultures
   research studied warriors across 23 countries
   studied if they changed appearance before war and if they killed, mutiliated and/or tortured victims
   warriors who significantly changed appearance through paint/costumes were more likely to be highly aggressive and torture victims

name a limitation of deindividuation

methedology
demand characteristics
lacks mundane realism - not having to do irl most of these things so lack of consequences
does not translate to real life

→ stanford prison experiment - researcher bias

explain 2 social psychological explanations for aggression

1. justified and unjustified frustration- pastor

2. frustration-aggression hypothesis- freud and dollard

explain justified and unjustified frustration

pastore
research 1:

• ppts asked to imagine how they’d feel in different circumstances
  → e.g. bus not stopping

• findings: anger in frustrating situations
  

research 2:

• distinguished between justified and unjustified aggression

• used diff scenarios then original research like bus not stopping due to:

  • no apparent reason (unjustified)

  • out of service displayed (justified)

• results: lower anger levels when justified

explain frustration-aggression hypothesis

dollard

• based on psychodynamic approach of cathartis

• aggression is always caused by frustration

• people are often aggressive to what frustrated them but often it’s not possible so displacement occurs
  

• dollard states that a scapegoat is needed to experience cathartis

• aggressive drives are similar to basic ones like thirst and hunger and we need to engage in aggressive behaviour to release this

what does dollard say aggression is highest when?

1. motivation to achieve is strong

2. we expect gratification

3. there’s nothing we can do

name a strength for unjustified and justified aggression and limitaton for frustration-aggression

• research found frustration is high when:

  • goal is near and you’re prevented from doing it

  • interruption is unexpected

  • interruption seems unjustified

• research:

  • ppts were told they can earn money from persuading to donate to charity

  • some ppts told to expect high response rate

  • others told not to expect any donations

  • respondants were all confederates

  • found high expectations = high aggression → slamming phone down/being rude

  • when ppts given justified reason, there was less aggression than unjustified

• levels of frustration determine aggression

• disputes idea that frustration in general causes it

name 2 strengths of frustration aggression

1. real world applications
   frustration hypothesis explains mass killings
   research suggests mass killings are often caused by social and economic difficulties
   → often leads to scapegoating then discrimination and aggression
   e.g. blamed jews for WW1 failures and economic failures after
   shows widespread and propaganda can be violent
   

2. supporting evidence
   meta analysis of 49 studies on displaced aggression
   ppts who were provoked and couldn’t retaliate against source were significantly more likely to be aggressive to an innocent party than non-provoked
   

name 1 limitation of social psychological explanations of aggression

1. other explanations
   slt, biological, evolutionary
   SLT might suggest that aggression is based on circumstances surrounding aggression than frustrastion
   → if talking about frustration aggression only, talk about lack of consideration of justified and unjustified

explain SLT and aggression

• banduara acknowledged aggression can be learnt through OC and CC
  → e.g. if a child is rewarded for ag they’re likely to do it again

• ag can also be learned indirectly through observational learning
  
  1. observational learning:

  • children and adults learn from aggressive live or symbolic models and learn the consequences of this behaviour

  • if ag is rewarded they learn this is effective
    → vicarious reinforcement

  • if ag is punished, they’re less likely to imidate
    → vicarious punishment
    

• meditational processes:

  • attention

  • retention

  • reproduction

  • motivation

explain bandura’s bobo doll experiment

aim: to see if role models can influence behaviour even when not present

sample: young children aged 3-5

procedure: children individually observed adult attacking an inflatable bobo doll. aggressive behaviours involved: kicking, hitting with mallet, throwing, shouting

children were then not allowed to play with toys to create frustration 

then they were taken to the room to play with the toys, including bobo doll

findings: children imitated behaviour they saw. almost direct copies of what the adults did → specific objects and phrases

other children who saw non-aggressive adults played normally

strongest imitation from researcher of same gender

what is maintence through direct experience (SLT)

reward for behaviour = repeated in similar situation

what self efficacy expectations (SLT)

children develop confidence to do aggressive actions

if they fail have less confidence = less likely to imitate

name 3 strengths of SLT

1. supporting evidence
   research had studied children observing adults actions
   model was either: rewarded, punished, or neither for aggression
   children who saw models rewarded were most likely to imitate and punished were least likely to
   

2. explains cultural differences
   kung san of Kalahari region had minimal ag due to parenting
   fighting children are not rewarded or punished → simply separated and distracted
   no physical punishment and ag in general is avoided and devalued in society
   no direct reinforcement or ag role models to little ag in children
   

3. real world applications
   study of ag children showed physically punishing children for ag reinforced the behaviour
   when taught effective discipline techniques like positively reinforcing good behaviour, parents reported ag was reduced in children

name a limitation of SLT

usage of lab experiments
developed theory through observations of young children’s behaviour in labs.
demand characteristics may have been present in the research, causing the validity questionable. children may have just been striking the bobo doll because they thought that’s what the experimenter wanted them to do. it also is unnatural scenario as adults would intervene in real life and not just allow the child to watch and then play with the same toy. this lacks ecological validity for how children learn in everyday life.

what are the 2 explanations for institutional aggression

1. deprivation model (situational factors)

2. importation model (dispositional factors)

explain the deprivation model

• prison is the source of stress and that influences inmates to be aggressive

• aggression is the reaction to adjusting to a life with changed psychological and physical factors (other fc)

• harsh conditions are stressful for inmates and lead to aggressive behaviour

• worsened by unpredictable prison regimes using lock-ups to control

• becomes adaptive to live in deprivation

name psychological factors in deprivation model

• loss of freedom

• loss of security

• boredom

• lonlieness

• lack of heterosexual intimacy

name physical factors in the deprivation model

• lack of space (closed cells)

• environmental stressors like crowding, invasion of personal space and overheating

• deprivation of material goods → leads to competition

explain research done on the deprivation model

• found inmate on inmate violence was more common in prisons with a higher proportion of female staff, overcrowding and inmates in protective custody

• shows prison environment is big factor for aggression as these are independent to personal characteristics

• reliably predicts aggression

explain 2 strengths of the deprivation model

1. supporting evidence
   - studied 370 prisons and and found situational factors like:
   lack of privacy, overcrowding, lack of meaningful activity
   signifcantly influenced aggression towards other inmates and staff
   further research found relationship between age of inmate and overcrowding
   → aggressive behaviour was more common in younger due to them having fewer coping stratergies
   

2. real world applications
   - helped make environmental changes
   research found reduced head, noise and crowding as well as maximising natural light can decrease violent behaviour
   done at HMP woodhill england
   → assaults on inmates and staff was almost eradicated
   drastic improvements to prisons

explain the importation model

• dispositional factors

• prisoners bring their own social histories and personalities to prison:
  beliefs, values, norms, attitudes, race, gender
  → may live in area where aggression is valued, respected and reinforced

• aggressive behaviour in prison isn’t different to outside prison → could be why they ended up there

• inmates use these traits to get through prison and establish power and access to resources

• predisposed to violence = likely to do it in any setting

• young inmates more likely to be agggressive

• gang members engage in a lot more aggressive acts

explain research about the dispositional model

• compared inmates with negative characteristics to inmates without negative characteristics

• negative dispositional factors were:
  childhood trauma, anger, history of substance abuse, history of violence

• found negative inmates were more likely to engage in suicidal activity, sexual misconduct and physical aggression

name a strength of the dispositional model

supporting evidence

• found in 4 different institutions, pre-institutional violence was best indicator for inmate violence

• regardless of particular features of institution

• supports model as it suggests aggression is brought into institution by offenders with ag traits

name a limitation of the dispositional model

gang membership doesn’t mean violence

• further research found that pre-prison gang violence doesn’t always predict violence

• found inmates with prior street gang involvement were no more likely to engage in violence than other inmates

  → however, may be explained by violent gang members often being isolated from general prison so limited access to violence

explain the intergration model

• merges ideas of both models

• now widely accepted as better explanation than either of them seperately

• both factors interact to cause aggression

name 3 ways media influences aggression

1. cognitive priming

2. desensitisation

3. disinhibition

explain cognitive priming

• repeat experience of aggression in media and images provides us with a ‘script’
  → scheme about how to act in situations

• explains why some people behave aggressively
  → once a child has learnt a script and committed it to memory, it can be used to define situations and guide how they act

• violent scripts are easily accessible as they are seen so often

• process is automatic and directs behaviour without us being aware

• script is triggered when we encounter a similar situation

explain research on cognitive priming

• fmri research compared brains of children when watching violent and non-violent programmes

• in both conditions, area that processes visual motion was active

• however, in violent condition, right hempishere was activated
  → regulates emotion, arousal, attention and responsible for episodic memory storage
  → this suggests violence is saved as a script

explain desensitisation

• when we see aggression, we normally have a physiological reaction and the sympathetic nervous system is activated
  → increased heart rate, higher blood pressure, sweat activity

• when children repeatedly view aggression on tv, physiological effects are reduced

• they become habituated to it and so it has a smaller impact

• promotes belief violence is an acceptable way to resolve conflicts
  → less empathy for victims, injuries dismissed, negative views about violence dissapate

explain research about desensitisation

• research showed ppts film straw dogs (with graphic rape scene)

• men showed greater acceptance of rape myths when watching mock rape trial if they watched this film
  → less sympathy to victims and less likely to find guilty than group without

• no effect on women
  

• ppt variables!!!! may be more aggressive people

explain disinhibition

• most societies hold belief aggression is anti social and harmful
  → therefore inhibit use of violence for conflict resolution

• learned directly and indirectly through SLT

• however, violent media exposure loosens restraints

• aggression is seen as normal and often justified/rewarded with minimised consequences

• created new social norms

explain research about disinhibition

• ppts who saw ag film depiciting ag as vengence gave more fake shocks to confederate than non-violent film

• suggests violent media may disinhibit ag behaviour if its effects are justified

name a strength of desensitiation

supporting evidence

• examined effect of violent games on responses to real life violence

• had ppts in 2 conditions: one played violent games for 20 mins, one played non-violent for 20

• all ppts shown footage of real life violence while having galvanic skin response (GSR) and heart rate measured

• violent condition had lowered heart rate and GSR in response to images
  → suggests desensitisation occured
  
  → don’t know how much they play outside of this of violent video games, and 20 mins isnt very long

name 2 strengths of cognitive priming

1. supporting research
   studied ice hockey players who were deliberately frustrated
   they were then shown a violent or non-violent film where an actor held a walkie talkie
   in the next game, the ones who watched violent film were more aggressive to referee with walkie talkie
   supports cog priming
   

2. real world applications
   claim that watching violent media creates violent scripts and leads to people interpreting cues as aggressive can lead to intervention
   can help reduce effective behaviour by challenging hostile scripts, encouraging alternatives like humour and negotiation→ CBT
   can also help with children’s development by ensuring other ways of dealing with conflict are shown

name 4 ways the effects of violent video games has been studied

1. experimental studies

2. correlational studies

3. longitudinal studies

4. meta-analysis

explain computer games and experimental studies

• lab experiment

• students played either violent or non-violent games

• carried out the taylor competitive reaction task (a measure of aggression)

• students delivered white noise blasts at chosen volumes to punish a (non-existent) opponent

• those who played violent games selected significantly higher volumes

explain violent video games and correlations

• studied teenagers with history of aggressive behaviour
  → e.g. hitting parents, teacher or involved in gang violence

• using structured interviews, gathered info about aggression and violent video game playing

• found offender behaviour was correlated with how often they played video games

explain video games and longitudinal studies

• done to see if there was a link between excessive tv viewing in childhood and aggressive behaviour in adulthood

• studied people born in new zealand in 1972

• found that time spent watching tv was a reliable predictor for aggressive behaviour
  → measured in terms of convictions for ag and violent crimes

• those who watched tv the most were more likely to be diagnosed with ASPD and have ag personality traits

• amount of tv in general rather than if violent
  
  ^{→ individual differences, may not have been convicted, may have time misrecorded, subject attrition, extraneous variables like family}

explain aggressive video-games and meta-analysis

• meta analysis of 136 studied (included the methods above)

• violent video games were associated with increase in aggressive behaviour, thoughts and feelings

• true across gender and culture

name 4 limitations of video games and aggression

1. no evidence for long term
   lots of research is done into short term negative effects
   less research about long term→ more speculative
   also research to suggest there are benefits of computer game use
   → may be misplaced and may be cathartic
   further lab and longitudinal research is required to investigate further
   needs large samples which are randomly selected from diff backgrounds
   

2. can’t establish cause and effect
   does not say if young people exhibit more negative behaviour as a result of playing these games, or if they play these games due to violent nature
   research suggests that people with more aggressive personalities like more aggressive games
   → may be the other way round
   

3. lack of consideration for other variables
   may have other factors that lead to aggression than violent video games
   research found evidence for the effect of video games was limited when you controlled risk factors like:
   mental health issues, family violence, aggressive personalities
   real cause of aggression could be these factors and violent people might just play violent games
   

4. other explanations of aggression