Paper 3 Aggression

• Proactive aggression


  deliberate aggression against another as a means of obtaining a desired goal
• Reactive aggression


  an impulsive retaliation for another person's intentional or accidental action, verbal or physical
• Limbic system


  neural system located below the cerebral hemispheres; associated with emotions and drives
• Limbic system process

  1) An action potential originates in one of the gray matter regions of the brain. 2) The action potential travels to another area of gray matter by projection fibers. 3) A new action potential is generated and sent to neighboring gray matter by association fibers. 4) Another action potential is generated and sent to the other cerebral hemisphere by commissural fibres.
• Papez-Maclean limbic theory

  - Amygdala linked to aggression, more activity in amygdala means more aggression

  - Hypothalamus regulate autonomic NS, regulate emotional response

  - Area of limbic system communicate with orbitofrontal cortex, control executive function
• AO3 Gospic

  - Amygdala increased activity in response to aggressive game when Ps chose to split money

  - Both agree to share money, split, if P refuse both get nothing

  - more activity in amygdala when confederate made unfair offer

  - Benzodiazapines reduce autonomic NS arousal
• AO3 Wong et al

  19 violent prisoners of broadmoor compared amygdala size, smaller in criminals, lack of generalisation, small sample
• Serotonin role in aggression

  Inhibits aggression, serotonin levels measured by turnover, by product of serotonin (how much broken down and produced)
• Seretonin deficiency hypothesis

  - Decreased serotonin in orbitofrontal cortex causes less self-control over limbic system aggressive impulses
• AO3 Strength Virkunnen

  Compare serotonin breakdown produced in violent impulsive and violent non-impulsive offenders, levels lower in impulsive offenders and sleep irregularities
• AO3 Strength mann et al

  - Dexfenfluramine (deplete serotonin in brain) to 35 adults

  - Questionnaire assess hostility levels, they increase after the drug
• AO3 Strength Berman

  - Participants given drug that boosted serotonin activity less likely to give electric shocks
• Testosterone role in aggression

  - levels are 8x higher in males than females

  - high levels in OFC decreases activity, less able to regulate aggressive behaviour from limbic system
• Wagner testosterone

  - Castrated mice and aggression levels went down, support testosterone theory increases aggression
• AO3 = Carre and Mehta dual hormone hypothesis

  high level of testosterone leads to aggression only when levels of cortisol are low
• AO3 = Popma et al

  found high levels of testosterone leads to aggression
• AO3 = Neural and hormonal mechanisms

  reductionist = only looks at hormones

  deterministic = not persons fault, hormones fault
• Genetic factors = Super males

  extra Y chromosome, more aggressive, lower in empathy, taller
• Genetic factors = Twin studies

  - Aggressive behaviour inherited

  - If aggression is innate, should see more aggression in monozygotic twins compared dizygotic twins
• Genetic factors = Coccaro et al

  Adult male MZ twins and DZ twins

  - Found concordance rates of 50% for MZ and 19% for DZ
• Genetic factors = AO3 Plomin

  - People create their own nurture by actively selecting environments 'appropriate' for nature

  - Niche picking

  Limitation = Kids don't have the same environment
• Genetic factors = adoption studies

  Levels aggression similar to biological parents shows it is genetic

  If levels of aggression are similar to adoptive parents it shows it is environmental
• Genetic factors = MAOA gene

  Breaks down serotonin, so increases aggression

  MAOA-L produces less enzyme

  MAOA-H produces more enzyme
• Genetic factors = Brunner et al

  - Studied extended families in Netherlands

  - Several males showed patterns of aggression

  - Identified MAOA gene fault when impulsive aggression, not present in other members

  - Deficient in MAOA
• Genetic factors = AO3 gene environment interaction

  - Question whether or not it was the victims fault, determinism

  - Have MAOA gene, but environment triggers gene
• Ethological explanation = Animal studies help understand

  - help define aggression, how occurs alongside other factors

  - We can understand the way helped evolutionary process

  - Animals in lab conditions controlled, not possible with humans
• Ethological explanation = Aggression is adaptive

  - Beneficial to survival as defeated animal dies or has to move

  - Species spread over wide area discover new resources and place, reduced selection pressures
• Ethological explanation = Aggression to establish dominance (Pettit et al)


  - studied children play groups, aggression plays a tole in the development of children's dominance

  - Get their own way
• Ethological explanation = Lorenz ritualistic approach

  - aggression is ritualistic and more adaptive

  - sustained injury due to aggression could impact reproductivity

  - teeth baring, deter without physical harm
• Ethological explanation = Innate releasing mechanisms

  - IRM built in physiological structure, neurones in brain

  - Environmental stimuli trigger IRM releasing specific behaviours

  - Behavioural sequence called FAP
• Ethological explanation = Lea - Fixed action pattern

  - Stereotyped

  - Unaffected by learning

  - Universal

  - Ballistic

  - Single purpose

  - Response to stimuli
• Ethological explanation = Tinbergen study

  - Male sticklebacks are territorial

  - Develop red sports on underbelly

  - Another male enters, FAP initiates

  - Sign stimulus trigggers

  - Present sticklebacks with wooden models
• Ethological explanation = Tinbergen findings

  - If model had red spot male would attack

  - No red spot = no attack

  - Aggressive FAP unchanging from one to another
• Ethological explanation = AO3 limitations Jane-Goodall

  - 4 year war = male chimps kill other groups systematically

  - violence continued even though victims surrendered

  - signals didn't stop aggressive behaviour, predicted by ethological explanation
• Ethological explanation = AO3 limitations Hunt

  - FAP influenced by environmental and learning

  - FAP behaviours vary from individuals

  - modifiable by experience 'modal behaviour pattern'

  - patterns of aggression more flexible
• Evolutionary explanation

  - environment of evolutionary adaptiveness

  - ancestral past when aggression would have helped with survival and reproduction
• Evolutionary explanations = Sexual jealousy


  - fear of losing mates affection

  - threat to relationship, show aggressive behaviour, same thing in infidelity, post threat to relationship and possibility of offspring to another male
• Evolutionary explanations = Wilson and Daly - mate retention strategies


  - prevent being cuckolded (fathering a child that isn't theirs)

  - direct guarding (vigilance over partner)

  - negative inducements (issues threats of consequences)
• Evolutionary explanations = Wilson et al

  - women who reported male retention strategies in their partner were 2x as likely to have suffered physical violence

  - 73% medical attention, 53% feared for lives
• Evolutionary explanations = Shackleford et al study

  Procedure = men and women 107 couples diff questionnaires married less than a year

  Findings = strong positive correlation between men and women reports