aggression

• Neural/hormonal

  Relating to the nervous system and hormones
• Neural/hormonal

  
  

  Gimmanco et al study -Animal study

  • More testosterone = more aggression
  • Female rats injected with testosterone = more aggressive behaviours eg mouse killing
• Neural/hormonal

  
  

  Dolan et al study - Maximum security prison - 60 males

  • Positive correlation between testosterone levels and aggression
  • Many had other psychiatric issues - cause and effect
• Neural/hormonal

  Gospic et al study Ultimatum Game - lab study

  2 players - proposer vs responder

  proposer proposed how the money should be split between the two and if the responder agreed they would both get the money as proposed

  but if the responder rejected this then both players would get nothing

  • High activity in amygdala when responders reject offers
  • Benzodiazepine drug - reduces arousal in autonomic nervous system - halved rejections - less aggression - less activity of amygdala
• Neural/hormonal

  Denson et al study

  • Serotonin in the orbitofrontal cortex
  • Serotonin at normal levels in OFC = more self-control
• Neural/hormonal

  Limbic system - a nextwork of subcortical structures - central area in the brain responsible for processing emotion and determines how we respond to environmental threats and challenges

  • amygdala - if malfunctioning, then levels of testosterone can be raised making aggressive behaviour more likely
• Neural/hormonal



  EVAL

  • association between the limbic system and aggression is only correlational - there are many parts in this system and it is still not clear which parts are implicated - could be some or could be all parts working together
• Neural/ hormonal - testosterone

  Testosterone is known to influence areas of the brain related to aggression. But evidence of the link between testosterone and aggression in humans is mixed and other hormones may also play a role.

  Dual-hormone hypothesis:

  • Carre and Mehta (2011) developed the dual-hormone hypothesis.
  • This claims that high levels of testosterone leads to aggressive behaviour only if levels of cortisol are low.
  • When cortisol is high, testosterone’s influence on aggression is blocked.
  • (Cortisol is a glucocorticoid hormone that plays a central role in the stress response).
• Neural/hormonal - genetic


  MAOA is an enzyme whose role is to mop up neurotransmitters in the brain after nerve impulses have been transmitted from one neuron to another - breaks down the neurotransmitter (especially serotonin) into constituent chemicals to be recycled or excreted, a process known as catabolism.

  • The production of the enzyme is determined by the MAOA gene and dysfunction in the operation of this gene may lead to abnormal activity of the MAOA enzyme - affect serotonin levels in the brain.
  • the warrior gene - a variant - low MAOA - MAOA-L
• Neural/hormonal

  Serotonin

  • Normal levels of serotonin in the orbitofrontal cortex are linked with reduced firing of neurons. This is associated with a greater degree of behavioural self-control.
  • Decreased serotonin may well disrupt the brain mechanism, reducing self-control and leading to an increase in impulsive behaviour, including aggression (Denson et al. 2012)
• Neural/hormonal


  EVAL

  • links are not always clear cut - sometimes a combination of OFC and amygdala/ serotonin - cause and effect is not clear
  • animal studies - extrapolation issues, ethical issues
  • correlational research - cause and effect cannot be established
  • deterministic - biochemistry - aggression cannot be controlled - implication for legal systems and punishing violent crimes
• Neural/hormonal - genetic


  Research ev

  Lea and Chambers - MAOA gene, named the warrior gene after the Maori people of New Zealand

  • 56% of male Maori have MAOA-L variant - more aggressive
  • low MAOA gene - abnormal activity of MAOA enzyme - serotonin = not broken down properly - abnormality leads to more aggressive behaviour
• Neural/hormonal - genetic 


  Research ev

  Brunner et al - 28 male Dutsch family with history of aggressive crimes

  • MAOA-L variant and low levels of MAOA enzyme - abnormal serotonin - less self control

  Frazzetto et al - gene and environment interactions

  • High levels of adult aggression - those who experienced extreme trauma before 15- eg sexual/physical abuse

  Coccaro - twin studies

  • 50% MZ twins - physical aggression
  • 19% Dz twins - physical aggression
• Neural/hormonal - genetic 


  EVAL

  • insufficient explanation - can only attempt to explain aggression in people with the MAOA-L variant - therefore cannot account for about 2/3 of men and most women
  • ignores role of nurture - similar upbringing in families - perhaps learnt rather than inherited
  • twin studies - overlooks the idea that MZ twins = more likely to be treated similarly by their environment (due to similar looks, upbringing), compared to DZ twins (who may look different) - ignores environmental factors
  • reductionist - oversimplifies aggression to genes
• Neural/hormonal - genetic

  MAOA gene

  A) standard

  B) break

  C) more

  D) less

  E) serotonin

  F) aggressive

  
• Ethological


  innate behaviour of humans and animals in their natural environment. Aggressive behaviour in animals is seen as adaptive (useful for increasing chances of survival)

  Ritualistic aggression - a series of behaviours carried out in a set order

  Lorenz: most aggressive encounters involve ritualistic signalling, rarely becoming physically aggressive - posture and bearing teeth

  • 2 wolves: loser will display their neck almost bowing to the winner - shows they are accepting defeat and allows the loser to continue to survive rather than being killed - appeasement display
• Ethological 


  1. stimulus - something in the environment triggers IRM
  2. innate releasing mechanism - a built-in physiological process or structure, for instance a network of neurons in the brain, triggering a FAP
  3. fixed action pattern - specific sequence of behaviours

  Lea: FAP

  • universal - same behaviour across the same species
  • ballistic - once the behaviour is triggered it follows an inevitable course and cannot be altered before it is completed.
  • A response to an identifiable specific sign stimulus
  • Unaffected by learning, the same for every individual regardless of experience
• Ethological 


  FAP - EVAL

  Modal action pattern:

  Fixed action patterns are therefore more flexible than implied by the term 'fixed'.

  Indeed many ethologists now prefer the term ‘modal action pattern’.

  For example, a FAP is typically made up of several aggressive behaviours that form a series, and the duration of each behaviour varies from one individual animal to another, (even in the same animal from one encounter to another.)
• Ethological 


  Research ev

  Brunner - MAOA

  28 aggressive males in a family - MAOA-L - innate - supports theological

  Nisbett - social norms/ culture

  • homocidal killings = more frequent in south over north

  Not innate but cultural - counter to ethological ex
• Ethological


  Research ev

  Tinbergen - sticklebacks

  • attacked wooden models of all shapes with a red spot on their underbelly
  • no red spot = not attack even if it looked similar

  across

  Red spot = stimulus triggering IRM which triggers FAP

  FAPs didn’t change across encounters and always ran its course - ballistic - supports ethological ex
• Ethological ex

  EVAL

  • deterministic - innate - no control over aggression - ignores cognitive factors - reasoning/ rational control
  • FAP are not universal - humans react differently even when put in the same situations
  • animal studies - extrapolation issues
• Evolutionary

  sexual jealousy is adaptive and drives aggression - anti-cuckoldry

  Mate retention strategies - Wilson and Daly (1996)

  • Direct guarding.
  • male vigilance over a partner’s behaviour e.g. checking who they’ve been seeing, coming home early, keeping tabs on their whereabouts, installing tracking apps on their mobiles, etc.
  • Negative inducements. E.g. issuing threats and dire consequences for infidelity.

  bullying - asserting dominance - survival of the fittest
• Evolutionary

  Research ev

  
  

  Wilson et al - male violence

  Women whose partners used male retention strategies = two times more likely to suffer physical violence at their hands

  • 73% need medical attention
  • 53% feared for their lives

  Volk et al - bullying and attraction

  Characteristics associated with bullying = attractive to the opposite sex - Male dominance and acquistion - Ward off potential rivals

  
  

  Campbell (1999) - sex differences in sexual jealousy

  • female with offspring = less aggressive - increase survival for herself and her child - verbal aggression over phsyical
• Evolutionary

  EVAL

  • doesn't consider cultural differences - Christianson - cultural differences - !Kung San tribe - discourage aggression - aggressive people: status and reputation within the community are diminished.
  • deterministic - aggression is out of one's control and is therefore excusable - trouble with punishing aggressive behaviour and the legal system
• Social-psychological ex

  Frustration-aggression hypothesis

  Dollard et al:

  • when we are prevented from achieving our goals, we respond with anger, hostility, and violence.
  • frustration always leads to aggression
  • aggression is always the result of frustration.

  
  

  if our attempts to achieve a goal are blocked by some external factor, we experience frustration.

  This frustration creates an aggressive drive, which leads to aggressive behaviour, such as a violent fantasy, verbal outburst and even physical violence.
• Social-psych

  Frustration-aggression hypothesis

  Factors affecting the likelihood of aggression occurring:

  • proximity to the goal - if the goal is likely/ close to being achieved, aggression is more likely - more frustrating situation
  • if the aggression will remove the barrier/external factor that causes the frustration then aggression is more likely - eg if your plumber is taking a long time to fix your sink, showing aggression may speed them up
• Social-psych

  Frustration-aggression hypothesis - EVAL

  
  

  Pastore - levels of aggression were lower in 'justified' situations than 'unjustified' situations - less frustration in 'justified' situations - shows frustration as a source of aggression

  • HOWEVER - not all frustration causes aggression

  
  

  
  

  • not universal - not everyone who is frustrated reacts with aggression - cry or withdraw
  • fight or flight - aggression as result of threat rather than frustration

  
  

  overall, it is a LIMITED explanation
• Social-psych

  SLT

  According to Bandura (1973), aggressive behaviour is learned in social contexts.

  Social learning theory does not deny that biological factors play a role in how we acquire aggressive behaviours.

  However it asserts that everything that really matters about aggression is learned.

  If aggressive behaviour is rewarded (or at least not punished), the child learns that aggression can be effective in getting what they want.

  This is known as vicarious reinforcement and it makes it more likely that the observing child will imitate the model’s aggressive behaviour.
• Social-psych


  EVAL

  • Bandura - bobo doll experiment - children imitated the aggressive behaviours of the role model they observed - HOWEVER - only shows short-term effect on aggression
  • less reductionist - considers biological factors affect aggression and cognitive factors - mediating processes
  • cultural differences - Kung San tribe - do not promote aggression
• social-psych

  Deindividuation is a psychological state in which individuals lose their identity and take on the social group's identity.

  • individuals are more likely to be aggressive when they are part of a group as they experience a loss of their identity
  • in a crowd, we lose restraint and are free to behave in ways we wouldn’t otherwise contemplate.
  • We lose our sense of individual identity, and we have a greater disregard for norms and laws.
  • Responsibility becomes shared throughout the crowd, so we experience less personal guilt at harmful aggression directed at others.
• Social-psy


  EVAL

  • Zimbardo - uniforms, sunglasses and a disguise helped the guards to deindividuate - helping them better conform to their social roles - causing them to be more aggressive
  • exact reasons behind deindividuation are unclear - many factors involved that may affect different individuals differently
  • practical application - darkness as a condition for deindividuation - ensure areas are well lit - decrease the likelihood of anti-social behaviour - CCTV
  • narrow application - aggression still occurs in situations where deindividuation cannot occur
• social-psy


  deindividuation

  Gergen - strangers were put in a dark room and told they wouldn't see each other again, they kissed and touched each other intimately

  when another group of participants were told they would see each other again, there was less intimate behaviour
• institutional aggression

  Dispositional Ex

  The importation model (Irwin and Cressey):

  • prisoners import their aggressive tendencies into prison

  Prisoners bring along with them norms, attitudes and history of past experiences. As a result the prisoners bring willingness to use violence to settle disputes within prison

  Aggression is ultimately caused by individual characteristics, which are ‘carried in’ with the prisoners. There is little or no fault of the prison environment

  Such inmates are predisposed to using violence and would have done so anyways in any setting
• Institutional 


  Dispositional ex

  Importation model

  Irwin and Cressey proposed 3 prison subcultures that influence inmates:

  1. criminal subculture - not telling on your fellow inmates - code of honour - trust and loyalty - some aggression
  2. convict subculture - strong power hierarchy - most likely to be aggressive - asserting dominance - gang culture
  3. conventional/ 'straight' subculture - new to prison - keep clear of the other subcultures - not generally aggressive
• Institutional 


  importation model - EVAL

  DeLisi - found a significant relationship between gang membership and prison aggression

  • idiographic approach - focusing on the experiences of prisoners as individuals and how that impacts their behaviour within prison - can explain why some prisoners are aggressive and why some are not
  • practical applications - shows that rehabilitation should consider home environments - decrease the likelihood of reoffending
  • ignores situational factors - prisons provide perfect conditions for people to be aggressive - physical conditions, corrupt staff
• institutional 


  Situational ex - deprivation model - Clemmers

  • prison environment increases aggression

  Deprivation:

  • of liberty and autonomy - prisoners cannot go and come as they please, no independence
  • of goods and services - no luxuries, no phones
  • of heterosexual relationships - single sex prison - lack of emotional intimacy - can lead to frustration and aggression
  • of security - lack of feelings of safety - heightened defensiveness and awareness - leads to aggression

  High temperature and noise – worsen the effects of overcrowding, causing aggressive behaviour
• Institutional 


  Situational - deprivation model - EVAL

  Lahm - situational and dispostitional

  • main predictors of violence = age and aggression levels - supports importation model - dispositional
  • also overcrowding affecting aggression - situational
  • frustration-aggression hypothesis - aggression = release of frustration - cathartic - prisoners are not stimulated - nothing else to do
  • humanistic approach - Maslow's hierarchy of needs - physiological and safety needs not met - self-actualisation = prevented - leads to negative behaviour
  • some prison violence occurs for no reason
• Media influences


  Computer games

  • exposure to violence
  • violent behaviours can be reinforced in real life as people receive positive reinforcement from playing these games
  • desensitised to violence - morality is skewed - we may no longer see violence as inappropriate because we are normalised to it
  • games also as an outlet - cartharsis - releasing stress and anger
• Media influences


  Computer games - EVAL

  Matthews et al - adolescents playing video games had decreased activity in their prefrontal lobe and increased activity in their amygdala - decrease in self-control and increased emotion - may lead to aggression

  • difficulties in establishing cause and effect - already aggressive people may just be more likely to play violent games
  • only explores the short-term consequences - long-term is not quite clear
  • lab studies - lacks mundane realism - not generalisable
• Media influences 


  desensitisation

  • repeated exposure to violent media allows individuals to normalise violent behaviour - reduced emotional, cognitive and behavioural response - increasing the likelihood to act violently