Aggression

Aggression

1. Biological explanations

   • Neural
     • Limbic system
       • Gospic et. al, Ultimatum Game: participants that reacted aggressively showed heightened response by amygdala on fMRI
         • Benzodiazepine drug also decreased activity of amygdala, highlighting its role in aggression
       • Hypothalamus, amygdala and parts of the hippocampus
     • Serotonin
       • Slows down and dampens neural activity
         • Therefore, decreased serotonin leads to reduced self-control and more impulsive behaviour (including aggression)
     • Evaluation
       • ✔ Causal link between serotonin function and aggression (due to research into the effect of drugs)
       • X Non-limbic brain structures are also involved in aggression so the neural regulation of aggression is more complex than theories focusing on the amygdala suggest
   • Hormonal
     • Testosterone
       • Androgen responsible for development of masculine features
     • Progesterone
       • Lowest levels are during and just after menstruation
         • Low levels of progesterone = increased aggression
     • Evaluation
       • ✔ Research from animal studies e.g. injecting female rats with testosterone increased mouse-killing
       • X Dual-hormone hypothesis: combined activity of testosterone and cortisol may be better predictor of aggression than either hormone alone
   • Genetic
     • MAOA gene
       • Regulates serotonin
         • Brunner et al. found low levels of MAOA in 28 men in large Dutch family who were extremely aggressive/violent
     • Twin studies
       • Coccaro et al. found men who were MZ twins had higher concordance rate for physical aggresion at 50% but 19% for DZ
     • Adoption studies
       • Waldman et al. (2002) carried out meta-analysis of adoption studies and found genetic influences accounted for 41% of variance in aggression
     • GxE interactions
       • Diathesis-stress model theory with genes and environment
     • Evaluation
       • ✔ Research support (as written for each AO1 point)
       • X Counterpoint of methodological issues e.g. twin studies: both individuals also share environment so concordance rates for genetics may be inflated

2. Ethological explanations

   • Innate releasing mechanisms
     • Biologically hard-wired mechanisms for aggression
       • Triggered by environmental cues
   • Ritualistic aggression
     • Allows species to establish dominance without actually needing to kill (to prevent extinction)
   • Ethology is the study of natural animal behaviour
     • Lorenz argued aggression is innate (like eating or drinking)

3. Social psychological explanations

   • Frustration-aggression hypothesis
   • Social learning theory
   • De-individuation

4. Evolutionary explanations

5. Institutional aggression (prisons)

   • Dispositional explanations
   • Situational explanations

6. Media influences

   • Effects of computer games
   • Desensitisation
   • Disinhibition
   • Cognitive priming