The document discusses various theories and mechanisms underlying aggression, including neural, hormonal, genetic, ethological, and psychological factors. It outlines how aggression can be influenced by biological components like testosterone and the MAOA gene, as well as environmental factors such as social learning and de-individuation. Additionally, it evaluates the impact of media violence and its desensitizing effects on aggression, highlighting the complexity and multifaceted nature of aggressive behavior.

1. Neural and hormonal mechanisms
 Neural mechanisms – limbic system (subcortical structures in the brain thought
to be closely involved in regulating emotional behaviour including
aggression), orbitofrontal cortex and serotonin (slows down neural activity,
decreased serotonin increases aggressive behaviour)
 Gospic et al. (2011) – ppts were subjected to mild provocation, when acting
aggressively fMRIs showed heightened amygdala response
 Hormonal mechanisms – testosterone (a hormone from the androgen group
that is produced mainly in the male testes, associated with aggressiveness),
progesterone (explains aggression in natal females, low progesterone suggests
increased aggression)
 Testosterone studies – castration of male animals to reduce aggression,
positive correlations between testosterone levels of prison pop. and violence
of crimes/behaviour

2. Neural and hormonal mechanisms –
eval
 Other brain structures – more recent research has shown that non-limbic
systems may have influence over aggression, such as the OFC, suggesting
neural regulation’s misunderstood complexity
 Drugs and serotonin – drugs that increase serotonin levels have been found to
also reduce levels of aggressive behaviour, strengthening proposed link
 Animal research – hormonal research from animals supports the idea that
testosterone affects aggression, ex. monkeys having increased testosterone
and aggression during mating season
 Dual-hormone hypothesis – mixed evidence of the link between testosterone
and aggression in humans, more likely that cortisol also has to be low in order
for this effect to be seen

3. Genetic factors
 MAOA gene – responsible for activity of certain enzymes that regulate
serotonin, very likely that the low variant (MAOA-L) increases aggression
 Twin studies – have found around 50% concordance for physically aggressive
acts between MZ twins and 19% in DZ twins, suggesting aggression has some
level of genetic basis
 Adoption studies – found that genetic influences accounted for around 41% of
variance in aggression
 Gene-environment interactions – Frazzetto et al. (2007) found an association
between antisocial aggression and MAOA-L, but only in men who had
experienced relatively severe early life trauma. This same aggression was not
present at similar levels in those who only had MAOA-L

4. Genetic factors - eval
 Research support – Mertins et al. (2011) found that those with MAOA-H are
exceptionally cooperative, which also supports the idea of MAOA-L being
involved in aggression
 However, the study also mentions the crucialness of non-genetic factors
which suggests genetics do not have total control
 Complex link – the precise mechanism is unclear and needs much more
detail to it, the relationship between serotonin and MAOA-L is not fully
understood
 Problems with twin studies – may lack validity, environmental factors are
crucial and inseparable in twins

5. Ethological explanation
 An explanation that seeks to understand the innate behaviour of animals by studying them in
their natural environments
 Suggests that the main function of aggression is adaptive, in that ‘defeated’ animals are rarely
killed but forced to make territory elsewhere + so this is a function to spread resources in a
species and establish a hierarchy
 Ritualistic aggression – Lorenz (1966) observed that intra-species fights rarely end in physical
damage but rather just patterns ended by ritualistic ‘appeasement displays’. Adaptive as if
fights ended in death the species would be threatened
 Innate releasing mechanisms – biological structures that are activated by an external stimulus
that triggers a FAP
 Fixed action patterns – sequences of stereotyped preprogramed behaviours, according to Lea
(1984) have these six features: unchanging, universal, unaffected by learning, always follow
through, single-purpose, and a response to an identifiable stimulus
 Tinbergen (1951) – observed male sticklebacks during mating season (red spots on
underbelly) and introduced them to an array of wooden figures, some fish-shaped, some not,
with either a spot or no spot. Found the fish to act aggressively to any wooden figure with a
red spot the same way, realistic-looking or not

6. Ethological explanations - eval
 Research support – Brunner et al. (1993) found that MAOA-L has strong links
to aggression, which supports the idea of aggression being genetic and
therefore adaptive as the ethological approach suggests
 However, aggressive behaviours can differ within countries with similar
genotypes (e.g. certain homicides more common in certain areas of a country)
which suggests there is a level of environmental influence
 Ritualistic aggression – Goodall (2010) observed ‘four-year war’ of male
chimps wherein there were systematic murders, which contrasts ethological
assumption that all intra-species aggression is ritualistic
 FAPs are not fixed – Hunt (1973) points out that FAPs can be more complex
and influenced by environmental factors, which suggests that the ethological
approach either under developed or negates this factor of their explanation
 Question whether or not aggression is truly innate and implications of such

7. Evolutionary explanation
 Explanation of sexual jealousy – major motive in males, as they can never be sure of
their child’s paternity and springs from a fear of cuckoldry, or having to raise another
man’s child- as this would be wasting resources on passing on rivals’ genes
 Mate retention strategies – direct guarding (male vigilance over female’s movements
and actions, more modernly this would be reading text messages etc.), negative
inducements (threats of violence against self or others if fidelity is perceived to be
broken or partner leaves)
 Wilson et al. (1995) – found that women who reported MRSs in their partners were 2x as
likely to experience DV, 73% of which needing medical attention and 53% claiming they
feared for their lives
 Male bullying – Volk et al. (2012) argue that characters associated with bullying attract
female mates, and that establishing a hierarchy in which you are the top promotes
health as an individual is less likely to have to fight for resources and therefore has a
better chance of reproduction
 Female bullying – Campbell (1999) suggests that this often takes place within a
relationship and is used to secure fidelity, so that resources continue to be provided

8. Evolutionary explanation - eval
 Gender differences – explains sex differences in aggression through adaption,
for example the idea that women do not get into physical altercations and use
verbal aggression because in past this would put them and their offspring in
danger of death
 Cultural differences – some cultures (ex. iKung San people) seem to be devoid
of aggression, suggesting that aggression cannot be entirely evolutionary or
adaptive like the explanation suggests
 However, cultural bias may get in the way of observations such as this- the
need for a certain perception or oddness of a different way of life skewing
conclusions drawn
 Real-world application – this explanation can be used practically to reduce
bullying through understanding the deficiencies causing aggressive behaviour
 This argument is biologically determinist

9. Frustration-aggression hypothesis
 Dollard et al. (1939) – first developed hypothesis; frustration always leads to
aggression and aggression is always the result of frustration, as aggression is a
psychological drive intended to solve issues when we cannot achieve our
goals; creates catharsis
 Frustration cannot always be expressed on appropriate target, often because
target is abstract/too powerful/not available, so aggression may be displaced
onto weaker available target
 Weapon effect – Berkowitz (1989) found that ppts would give higher fake
shocks to a confed. if guns were present in the vicinity, suggesting aggressive
cues/weapons stimulates aggression
 Green (1968) – studies f-a hypothesis, found that when prevented from
achieving goals (finishing puzzle) by confed, ppts would give higher fake
shocks than those who simply did not finish the puzzle as it was impossible

10. Frustration-aggression hypothesis -
eval
 Research support – a meta-analysis found that frustrated ppts who were
provoked but unable to aggress against provoker were always more likely to
aggress against innocent party, supporting F-A hypothesis
 Role of catharsis – Bushman (2002) found ppts who vented anger by punching
a punching bag actually became more aggressive, compared to ppts who did
nothing, which goes against Dollard’s suggestions
 Frustration-aggression link – complex and not fully understood, therefore
making it an inadequate explanation at current time and for all scenarios
 However, Berkowitz (1989) suggested the negative effect theory to improve
FAH, arguing frustration is just one possible stimuli, therefore frustration and
its link to aggression is not redundant but rather just fractional

11. Social learning theory
 Aggression can be learned directly through operant conditioning, e.g. a child
snatching a toy means they now have that toy and the aggressive behaviour is
positively reinforced
 Observational learning – children can learn aggressive behaviours through
vicarious reinforcement, watching others not get punished or be praised for
antisocial behaviour
 Cognitive conditions for learning – attention, retention, reproduction,
motivation
 Self-efficacy – confidence in aggressive actions achieving goals, an individual
with high self-efficacy is more likely to be more aggressive as they have a log
of previous successful outcomes and believe more behaviour will be met with
further success
 Bandura (1961) bobo doll experiment can be adjusted to be considered within
the context of aggression

12. Social learning theory - eval
 Research support – Poulin and Boivin (2000) found that aggressive boys aged
9 to 12 often form friendships with other aggressive boys, which creates an
echo chamber of positive reinforcement and vicarious reinforcement of
aggression, in accordance with SLT
 However, this is only for proactive aggression and no such similarity is found
within reactive aggression, suggesting SLT can only form a partial explanation
of certain scenarios
 Real-world application – SLT can be applied in child development to reduce
aggression by ensuring that children do not see aggression met with positivity
or neutrality
 Biological influences – this explanation underestimates biological factors such
as MAOA-L and testosterone, making it an incomplete explanation of
aggressive behaviour
 Research methods – much of this research has a lab setting, which brings into
question its practicality in real-life learning due to artificial nature of tasks

13. De-individuation
 A psychological state in which an individual loses their personal identity and
takes on the identity of the social group they are in, resulting in potential
decreased concern about the evaluation of others
 Link to aggression – in a de-individuated state behaviour becomes emotional,
impulsive, irrational, disinhibited and anti-normative, which may lead to
aggressive behaviours, supposedly due to the anonymity a crowd provides
 Reduced self awareness – private self awareness (how we pay attention to our
own thoughts and feelings) and public self awareness (awareness of others’
opinions on our behaviour) both decrease in crowd scenarios
 Dodd (1985) – asked of psychology students ‘if they could do anything with a
guarantee there would be no repercussions what would you do?’, found that
36% was antisocial, 26% were crimes, a few severe crimes. Only 6% chose
prosocial behaviours, demonstrating link between antisocial behaviour and
anonymity

14. De-individuation - eval
 Research support – Douglas and McGarty (2001) found that in online chats,
there was a strong positive correlation between aggressive messaging and
levels of anonymity provided
 However, Gergen et al. (1973) found in a ‘deviance in the dark’ study that
anonymity caused intimate behaviours rather than aggression, suggesting
that anonymity does not always result in aggression
 Real-world de-individuation – scenarios of aggressive crowd behaviour in
real life, for example baiters of suicidal individuals attempting to end their
lives in front of a crowd (e.g. off of buildings)
 Role of norms – de-individuated behaviour may actually be normative, as
they are antisocial norms in of themselves, which goes against the idea
that de-individuation causes action against social norms

15. Institutional aggression in prisons
 The importation model – Irwin and Cressey’s (1962) suggests that prison inmates import
and outside world culture into the separated world of the prison, the willingness of
using violence to settle disputes reflects pre-prison life; therefore aggression is a result
of individual characteristics and not environment
 DeLisi et al. (2011) – studied juvenile offenders in California, found that those who had
‘negative features’ of past life were more willing to engage in suicidal behaviour/sexual
misconduct/physical aggression than a control group of offenders without ‘negative
features’
 The deprivation model – Clemmer’s (1958) model suggests the environment of prison is
to blame for aggressive behaviour seeing as prisons deprive prisoners of ‘necessary’
stimuli such as freedom and sexual intimacy, as well as being unpredictable and
festering frustration
 Steiner (2009) – investigated factors predicting aggression in 512 US prisons, found that
inmate-on-inmate violence was more likely in prisons where there was a higher
proportion of female staff, overcrowding, and higher number of protected custody
inmates

16. Institutional aggression in prisons -
eval
 Research support – Camp and Gaes (2005) studied 561 male inmates with
similar criminal histories, half placed in low and half in high security prisons;
found that after two years there was no significant difference in prisoners
involved in aggressive acts (33% and 36%), supports dispositional explanation
 Ignores key factors – Dilulio (1991) points out the dispositional explanation
ignores other influences on behaviour, proposing poorly managed prisons
have more violent inmates, suggesting importation is an inadequate
explanation
 Research support – Cunningham et al. (2010) analysed 35 inmate homicides,
found that the motives were often linked to deprivations of normal ‘goods’ or
activities within prison, which supports the deprivation model
 Contradictory research – Hensley et al. (2002) studied 256 inmates of 2
Mississippi prisons (allows conjugal visits), and found no link between
involvement in these visits and reduced aggressive behaviour, contrasting the
deprivation model

17. Media influences
 Excessive TV viewing – Robertson et al. (2013) studied over 1000 New Zealanders over
26 years, found that time spent watching TV in adolescence and adulthood to be a
reliable predictor of aggressive behaviour in adulthood
 Violent film content – Bandura et al. (1963) modified original Bobo doll into a film to
watch, found children to similarly imitate the aggressive behaviour even with a cartoon
version
 Paik and Comstock (1994) – meta-analysis of 200 studies, found significant positive
correlation between viewing media violence and antisocial behaviour; however this was
only 10% of variance, implying minor role of TV/film compared to other medias
 Computer games – Bartholow and Anderson (2002) used TCRTT to study aggression in
students, having them either play mortal kombat or a golfing game beforehand; found
that on average the MK group gave higher blasts of white noise to a fake opponent
 Correlational studies also provide much basis for further investigations on this topic

18. Media influences - eval
 Defining aggression – aggression in these studies is defined differently,
meaning the conclusions drawn could be completely different but treated
the same, as well as the fact that it does not cover all forms of aggression
 However, meta-analyses help to overcome this problem and by including
various definitions within them can help compare the data more uniformly
 Unsupported conclusions – due to poor methodology, researchers may be
guilty of premature conclusions that are not properly supported by
evidence from studies
 Explaining research findings – the findings of these studies can be
explained though SLT, suggesting that they have practical basis and
validity as a real explanation of aggression

19. Desensitisation, disinhibition and
cognitive priming
 Desensitisation – regularly when viewing upsetting or violent media our sympathetic ANS
causes physiological changes in the body, but repeated viewing decreases these changes
significantly (especially in children), encouraging those who view it to see aggression as a
proper method of conflict solving
 Weisz and Earls (1995) – ppts were shown graphic rape from a film, then a re-enactment of a
rape trial; compared with those who watched a nonviolent film, male ppts were less
sympathetic of the victim and readily accepted rape myths, no such effect was found in
female ppts
 Disinhibition – aggressive behaviour being made out to be justified or normative in media
encourages viewers to think of it that way also, they become less socially averse to displays of
it and more likely to act aggressively
 Cognitive priming – repeated viewing of aggressive media encourages ‘priming’ of aggression
through development of a ‘script’ for perceivably aggressive situations, readiness for
aggression in individuals likely to act
 Fischer and Greitemeyer (2006) – men listened to women-degrading song lyrics, and
compared with neutral lyrics were more likely to pick out negative qualities of women and
behave more aggressively towards a female confederate; this was repeated with women and
the same effect was found

20. Desensitisation, disinhibition and
cognitive priming - eval
 Desensitisation – Krahe et al. (2011) measured physiological arousal during
violent or non-violent films and found habitual viewers of violence to have
lower arousal; but desensitisation cannot explain all instances of aggression,
and the theory of catharsis may be more accurate in ways
 Disinhibition – Berkowitz and Alioto (1973) found ppts who viewed a movie
depicting aggression as vengeance gave more and longer fake shocks, making
violence seem socially acceptable encourages it; disinhibition can also explain
cartoon violence as there is no perceived wrongness to it
 Cognitive priming – Bushman and Anderson (2002) argued that those who
habitually view violence are more likely to perceive cues as violent and
therefore more likely to act aggressively themselves, as they have more
‘scripts’; but much research into this has uncontrolled confounding variables
such as complexity of games in the F+G study, once complexity of game was
controlled there was little difference in effects of violence