Biological Explanations for Aggression

HideShow resource information
View mindmap
  • Biological Explanations for Aggression
    • Limbic System
      • Hippocamus
        • Stores LTM, responsible for comparing the current stimuli to past experiences
          • Bacardi et al
            • Multiple violent offenders show abnormal hippocampal functioning.
              • Unrepresentative sample - all prisoners
              • Correlative - cannot establish causation
      • Amygdala
        • Responsible for determining an emotional response
          • Pardini et al.
            • Connection between low amygdala volume in boys and later aggressive character traits in adulthood
              • Gender bias - all male sample could lead to androcentrism
          • Has been shown to work with the OFC - which is not part of the limbic system. This shows the theory may be incomplete.
            • OFC - Orbitofrontal Cortex
          • Removing the amygdala in monkeys results in loss of status in the group
            • Animal model, cannot be extrapolated
          • Gospic et al.
            • Pps playing the Ultimate Game (a bidding game involving rejection) had fewer aggressive responses when the amygdala was suppressed using a drug
              • Used fMRI (functional magnetic resonance imaging) to directly study inactivity - increasing validity
              • Drug also suppressed the entire ANS (autonomic nervous system) - which could have lead to another responsible region being suppressed
      • Hypothalamus
        • Responsible for regulating the release of hormones in response to aggressive stimuli
    • Neurotransmitters
      • Serotonin is thought to play an inhibitory role in the response to stimuli
        • Virkkunen
          • Compared the amount of serotonin breakdown fluid in the cerebrospinal fluid of impulsive non-violent offender and impulsive violent offenders.
            • Violent offenders had a lower concentration of serotonin breakdown fluid that non-violent
              • Correlative - cannot establish causation
        • Berman
          • Drugs that increased serotonin activity decreased frequency and severity of electric shocks in a Milgram-esque game
            • Use of a control group increases internal validity, allowing for a comparison
            • Ethics - protection from harm infringed due to electric shocks
    • Deterministic
      • Aggression is the result of biological factors beyond the control of the individual
    • Hormones
      • Testosterone is associated with high levels of aggression
        • Mehta and Joseph
          • Measured testosterone in men before and after they lost a competitive game
            • Pps were allowed to re-challenge the opponent. Those whose T had increased were more likely (73%) to re-challenge than those whose T had decreased (22%)
    • Genes
      • Twins
        • Coccaro et al.
          • In adult male twins, the concordance for direct physical aggression was 50% for MZ (monozygotic) twins and 19% for DZ (dizygotic) twins
            • Not 100% - other factors must be in play
            • Adult model - there is significant evidence to suggest that the genome changes over the course of someone's life, meaning at birth concordance of genes could have been higher
            • Environmental factors - MZ twins tend to be treated the same way due to being identical whereas DZ twins are distinguishable and will be treated differently
      • MAOA
        • The MAOA gene codes for the creation of an enzyme that breaks down neurotransmitters after impulses are fired.
        • A variant of this gene lowers the activity of the MAOA enzyme, which is associated with aggression
          • Brunner
            • 28 men in a large Dutch family with a history of violent, impulsive crime all had the gene variant
              • One family, cannot generalise
              • Correlation not causation
          • Frazetto et al.
            • Diathesis-Stress may play more of a role
            • Found that the MAOA variant must be accompanied by trauma in the first 15 years of life in order to create aggression


No comments have yet been made

Similar Psychology resources:

See all Psychology resources »See all Aggression resources »