This document is detailed revision notes with all you could ever need to know on the whole AQA A-level Psychology Aggression topic, including AO1 and AO3 content. The notes are subdivided into the subtopics used by the textbook. They include the content from the textbook, which has been combined wi...
Aggression
Neural and hormonal mechanisms in
aggression
Hot-blooded/reactive aggression: impulsive, angry, physiological arousal
Cold-blooded/proactive aggression: premeditated
Economic implications of aggression: prisoners, lawyers + courts, police, NHs,
property damage, therapy, lost worker productivity.
Neural mechanisms in aggression
Papez and Maclean: limbic system linked to emotional behaviour including aggression.
Limbic system = hypothalamus, amygdala and parts of hippocampus (+ others).
Reactivity of amygdala in humans and other mammals is an important predictor of
aggressive behaviour (more responsive = more aggressive).
- Role in assessing and responding to environmental threats
Gospic et al.:
o Participants played the ‘ultimatum game’ – ‘Proposer’ given money, has to offer
some to ‘Responder’ – if B accepts they both keep, if B accepts they both lose
o B subjected to mild provocation (offered unfair amounts)
o When they rejected the offer (aggression) fMRI scans showed fast and
heightened response by amygdala.
o Benzodiazepine drug (reduces arousal of autonomic nervous system) taken
before provocation = decreased activity of amygdala, halved number of
rejections
o Association amygdala-reactive aggression
Serotonin has widespread inhibitory effects in the brain.
- Normal levels of serotonin in the orbitofrontal cortex (OFC) are linked with
reduced firing of neurons --> greater behavioural self-control
- Serotonin deficiency = reduced self-control, increase in impulsive behaviour inc.
aggression (Denson et al.)
Virkkunen et al.: compared levels of serotonin breakdown product (metabolite 5-HIAA)
in the cerebrospinal fluid of violent impulsive and violent non-impulsive offenders.
- Levels lower in the impulsive offenders
Evaluation
Other brain structures
, o Research shows that non-limbic brain structures are also involved in
aggression
o Limbic structures e.g. amygdala function with the OFC (not part of limbic
system)
o OFC involved in impulse regulation + inhibition of aggressive behaviour
o Coccaro et al. – OFC activity reduced in psychiatric disorders that feature
aggression
o Reduced activity disrupts impulse-control function --> aggression
o More complex
Drugs and serotonin
o Drugs (e.g. paroxetine) that increase serotonin have been found to also
reduce levels of aggressive behaviour
o Berman et al.: gave ppts placebo/paroxetine, then lab-based game
involving giving and receiving electric shocks in response to provocation
(e.g. insults)
o Paroxetine group: fewer and less intense shocks
o Causal evidence
Supporting research for relationship the amygdala and aggression
o Kluver and Bucy: destruction of amygdala in monkey dominant in social
group – lost dominance
o Mark and Ervin: women with painless stimulation to amygdala became
enraged, smashed guitar against wall
Direct or indirect?
o Neural factors directly linked – Gospic et al. + serotonin reduces
aggression by inhibiting neuronal activity
o Indirect: Denson et al. – link between serotonin and aggression indirect as
other factors e.g. social, psychological may influence it
Correlational research
o Ethics – provoking aggression not protecting from harm
o Brain scans
o Changes to OFC/amygdala not necessarily cause of aggression or vv
o Could be intervening variable
Hormonal mechanisms in aggression
Testosterone is an androgen responsible for the development of masculine features.
Linked to aggressive behaviour because:
- Males more aggressive than females
- Males become more aggressive to other males when testosterone levels are
highest in development (after 20 years of age) (Daly and Wilson)
Role in regulating social behaviour.
Castration studies: removing testes reduces aggression in males of many species,
giving injections of testosterone to same animals restores aggressive behaviour (e.g.
Giammanco et al.)
, Prison studies: Dolan et al. – positive correlation between testosterone levels and
aggressive behaviours in sample of 60 male offenders in UK maximum security
hospitals
- Men mostly had personality disorders (e.g. psychopathy) + histories of
impulsively violent behaviour
Progesterone (female ovarian hormone) has role in female aggression.
- Levels vary during the ovulation cycle, lowest during and just after menstruation
Ziomkiewicz et al.: negative correlation between progesterone levels and self-
reported aggression
- Low levels = aggression
Evaluation
Animal research
o Giammanco et al. – review of studies, confirms role of testosterone
o Male rhesus macaque monkeys – increase in testosterone levels and
aggressive behaviour during mating season
o Rats – castration of males reduces testosterone and mouse-killing
behaviour, injecting female rats w testosterone increases mouse-killing
COUNTERPOINT
o Animal research validity
o Low construct validity – aggression for dominance in social group
o Mazur – must distinguish aggression from dominance
o Aggression – individuals want to injure, dominance – to keep status
o Animals artificially enhanced with testosterone – dominance not injury
o Testosterone can make females nicer to obtain status
Empirical evidence
o Mehta and Josephs – changes in testosterone levels before and after
losing a competitive game + then could challenge again or do an
unrelated activity
o Rising testosterone – 73% re-challenged vs 22% falling
o Loss of status --> increased testosterone and aggression
o Correlational link, validity
Dual hormone hypothesis
o Carre and Mehta: high levels of testosterone cause aggression but only
when cortisol is low
o When cortisol high, testosterone’s influence on aggression is blocked
o Cortisol plays role in body’s response to chronic stress
o Combined activity really the predictor of aggression over either alone
o Reductionist
Animal research
o Hormones in humans and animals likely to be very similar
o But aggressive behaviour in humans more complex
o E.g. cortisol findings applied to only human aggression
o Cognitive factors in humans esp. in ‘cold-blooded’ proactive aggression
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