Aggression - Not on Spec

Papez and Maclean limbic system
More responsive amygdala = more aggression
Gospic 2011
Denson 2012
Virkkunen 1994

Linked to emotion
Hypothalamus
Amygdala
Hippocampus

Gave benzodiazepine (lowers ANS arousal)
Reduced amygdala acitivity
Reduced aggression

Lowered serotonin
Reduced self control
More impulsive
More aggression

Metabolite 5-HIAA breaks down serotonin
Violent impulsive offenders had low 5-HIAA compared to non violent

+ Evidence for serotonin
- Only if there's pre-existing aggression
- Amygdala = reductionist

Berman
A = placebo
B = paroxetine (increases serotonin)
Pps gave shocks in response to provocation
B = more shocks
- Only if pp had pré existing aggression

Coccaro
Psychopath-aggression link
Psychopaths = low activity in orbital frontal cortex
Not just amygdala

Aggression more likely in males than females
Daly and Wilson
Dolan 2001
Giammenco 2005
Low progesterone = more aggression in women

Males most aggressive when at testosterone peak
20y+

+ive correlation between testosterone and aggression
Looked at male offenders with violent impulsive behaviour

Non human animals
Castration reduced aggression
Testosterone injections increased aggression

- Testosterone = too simple
- Ignores nature

Carre and Mehta
Dual hormone hypothesis
Increased testosterone and low cortisol = aggression
High cortisol tops testosterone aggression link

High amygdala activity/high testosterone doesn't determine aggression
Suggests behaviour cannot be controlled
SLT and frustration-aggression

XYY
Twin studies - Coccaro 1997
Adoption - Rhee and Waldmen
MAOA gene

Believed extra Y = increased aggression
Court-Brown believed XYY should remain hospitalised

Twin studies
Examined concordence of criminal behaviour
Physical aggression:
MZ = 50%
DZ = 19%
Verbal aggression:
MZ = 28%
DZ = 7%

Meta analysis of adoption
Genes account for 41% variation in aggression

Regulates serotonin
Reduced activity of MAOA enzyme = more aggressive
MAOA - L (low) = warrior gene
MAOA enzyme breaks down serotonin

Lea and Chambers 2007
56% New Zealand Maori males had MAOA gene (Maori warriors were fierce)
34% caucasians

+ MAOA support
- Nature of nurture
- XYY counter evidence
- Twin study support
- MAOA-L and serotonin link unclear

Brunner
28 men of a Dutch family
Repeatedly involved in aggression - rape, attempted murder, assault
Had MAOA-L and low MAO-A activity (the enzyme)
- Nature or nurture?

Theilgaard
XYY = taller but not aggressive

Nature or nurture
Not 100% for MZ

Low serotonin = increased aggression
MAOA-L = reduced break down of serotonin so more serotonin and reduced aggression
MAOA-L disrupts serotonin (not increase or decrease)

Vicarious reinforcement
Identification
Modelling
Mediational processes
Self-efficacy
Bandura 1961

Attention
Retention
Motor reproduction
Motivation

Extent to which we believe our actions will achieve a desired goal
If aggression is successful in achieving a goal, we are more likely to repeat it

Bobo doll study
Young children watched adult assault/play with bobo doll
Copied aggressive behaviour
Boys were more physically aggressive than girls
Boys were more likely to imitate a same sex model compared to girls

+ Further support
- Biology as well
+ Real life application
- Very high control
- Ignored biology

Bandura 1963
A = filmed aggressive model
B = cartoon aggressive model
C = real aggressive model
D = no aggressive model
Chidlren most aggressive for (highest) B A C D (lowest)
- Boys more aggressive than girls so biology also involved

Modelling non-aggressive behaviour to children increases chance of non-aggressive behaviour
Useful in schools

Low eco validity
Bobo doll cannot retaliate
Is designed to be hit

Instict for aggression
Evolutionary advantage to be aggressive
Influence of limbic system etc.

Dollard 1939
Reasons why frustration doesn't always cause aggression
Defense mechanisms
Weapons effect - Berkowitz 1989

1 Attempts to reach a goal are blocked
2 Aggressive drive
3 Aggression
4 Aggressive behaviour
5 Catharsis (aggressive drive is satisfied)

1 Frustration is abstract (money / governement)
2 Cause is very powerful and risk of punishment (teacher)
3 Cause is unavailabel (person leaves)

Sublimation
Displacement

Using aggression in acceptable activities
Sport

Directing aggression outwards onto something or someone else

Weapons effect
Frustration creates readiness for aggression
Frustration only causes aggression when there's an aggressive cue (eg. weapon)

+ Support
+ Displacement support
- Aggression doesn't always cause catharsis
- Open carry laws
+ Remove guns = reduced aggression?

Geen
Male pps complete a jigsaw
A = impossible
B = student interfering
C = insulted by confederate
Pps then gave shocks to confederate in separate task
C highest intensity, B, A lowest intensity
All gave more intense shocks than control

Newhall
Meta analysis of 49 studies
Provoked pps = more likely to be aggressive to innocent 3rd party than not provoked

Bushman
Pps who hit punchbag = more aggressive and angry than control

Some US states allow ppl to carry weapons without concealment
Suggests aggression is more likely
+ Remove guns = reduced aggression?

Le Bon
Alone vs in a crowd
How deindividuation occurs
Dixon and Mahendra 2012
Prentice-Dunn and Rogers 1982
Private self awareness
Public self awareness

Psychological state in which an individual loses their personal identity and takes on identity of social group

Lose individual identity
Lose restraint
Lose responsibility
Disregard norms of individual behaviour
Behaviour is a shared responsibility
Reduced personal guilt for harm or antisocial behaviour

Restraints on aggressive behaviour are relaxed
'Live for the moment'
Don't consider long term plans

Drugs
Alcohol
Darkness
Uniforms
Masks and disguises

Deindividuation =
Reduced fear of retribution
Bigger the crowd, the more anonymous the individuals
Anonymity means ppl are less likely to be judged negatively

Deindividuation increases aggression because of consequences of anonymity
Reduced private self awareness
Reduced public self awareness

Paying attention to our own thoughts and feelings

How much we care about what other ppl think about our behaviour

+ Support
- Deindividuated doesn't always lead to aggression
+ High eco support
- Deindividuation doesn't always lead to aggression
- Conform to group norms (not always aggression)

Johnson and Downing
A = dressed as nurses
B = dressed as KKK
KKK = gave stronger electric shocks
- Deindividuated nurses = less aggressive so deindividuation doesn't always lead to aggression

Mann
21 newspaper reports where crowds baited suicide jumper to jump
Dark
Large crowd
Far away

Gergen
A = 8 strangers in light box for 60 mins
B = 8 strangers in dark box for 60 mins
A = chatty and not physical
B = physical, gentle and caring (hugging and kissing)

Spears and Lea
Follow group norms regardless whether good or bad
Take on social > personal identity

Aggression is adaptive
Reduce competition
Establish dominance hierarchies
Ritualistic aggression
Innate releasing mechanism
Fixed action pattern

Innate study of animal behaviour

Defeated animals rarely killed
Forced into different territory
Ensure species survival
Reduces competition

Aggression used to climb hierarchy
High status = better access to resources and mates

Series of behaviours carried out in a set pattern

Lorenz 1966
Intraspecies fighting
Low physical contact or harm
Lots of threat displays
Ritualistic appeasement displays (signal end of aggression)

Built in physiological process that causes a fixed action pattern when stimulated

Ballistic (once triggered, always completed)
Response to specific stimulus
Universal
Unaffected by learning
Sterotypical
Single purpose

Tinbergen 1951

Male sticklebacks = red underbelly in mating season
Shown shapes
Red spot = FAP
Aggressive reaction always completed

+ Support
- Not universal
- Non-human animals
- Ritualistic aggression counter

Other research supports genetic explanation
Brunner MAOA-L
Coccaro
Lea and Chambers

Nisbett
Southern USA = more likely to be murdered than north
Due to reactive aggression and cultural norms of honour

Different physiology, culture, language and environment
Chimps and sticklebacks

Goodall
Male Chimps in Tanzania
Systematic slaughtering of males in other troops
Coordinated and premeditated
Aggression continued despite ritualistic appeasement displays

Jealousy is adaptive
Cuckoldry
Mate retention strategies - Wilson and Daly 1996
Wilson 1995
War - Livingstone Smith 2017

M'en never sure if Child is theirs
Threat of cuckoldry (raising someone else's offspring)
Waste of resources and reproductive opportunity
Jealousy deters partner from adultery

Mate retention strategies
Direct guarding (coming home early, checking texts)
Negative inducement (threatening violence if partner leaves or cheats)

Pps = women who reported mate retention strategies
X2 = physical violence from partner
73% required medical attention
53% feared for life

War
Displays of male aggression and bravery in warfare was advantageous
More attractive
Higher social status
Stronger intra group bonds
Share benefits and resources of social status

+ Explains gender differences
+ War support
- Not universal
- Biological differences

Campbell
Female physical aggression puts mother and child at risk
Females more likely to use verbal aggression to retain partner

Chagnon
Male warriors in traditional societies had more reproductive partners
Campbell
Most violent gang members had highest status

Kung San = discourage aggression and shun children who display it
Yanamamo = very aggressive and 50% males die by homicide

Frustration
Deindividuation
SLT
Dollard
Berkowitz