Agression Flashcards
Neural mechanisms in aggression - AO1
The limbic system - linked to emotional behaviours, including aggression. Contains hypothalamus, amygdala and parts of hippocampus. Reactivity of amygdala is an important predictor of aggressive behaviour.
Gospic study - fMRI study showed response from amygdala when participants behaved aggressively following provocation. A benzodiazepine drug taken before decreased activity in the amygdala and halved the number of aggressive responses.
Orbitofrontal cortex and serotonin - serotonin slows down and calms neuronal activity. Decreased serotonin levels in the orbitofrontal cortex disrupts self-control and leads to more impulsive behaviour including aggression.
Virkukken study found lower levels of a serotonin-breakdown product in the cerebrospinal fluid of violent inmates compared to non-impulsive ones.
Neural mechanisms in aggression - AO3
+ Paroxetine study - participants who took a drug that increased serotonin levels gave less electric shocks. Evidence of a causal link between serotonin and aggression.
C.P is this a good measure of aggression?
- Reductionist explanation. Ignores social and psychological explanations for aggression. Only a partial explanation.
+ Raine et al’ scanned the brains of 41 murderers and 41 controls. They found, using PET scans, that some had abnormalities in the way that their limbic systems functioned.
C.P - bidirectional - aggression may cause changes to limbic system
Hormonal mechanisms in aggression - AO1
Testosterone - increased levels linked with aggression in human offenders and castrated mammals. Men most aggressive at 20, when their testosterone is at its highest.
Correlation between testosterone levels and aggressive behaviour in a sample of offenders in a UK max security prison.
Progesterone - Low levels linked to higher aggression in women. Lowest during and after menstruation - PMS.
Hormonal mechanisms in aggression - AO3
+ Animal research - testosterone and aggression higher in mating season (monkeys), mouse-killing lower in castrated male rats and higher in female rats given testosterone.
- Dual-hormone hypothesis - testosterone leads to aggression only when cortisol levels are low. High cortisol levels blocks testosterone. Mixed evidence for just testosterone.
- Are animal studies useful? Hormonal mechanisms similar however more complex in humans (cortisol only applies to humans and cognitive factors)
Genetic factors in aggression - AO1
Twin studies - concordance rates for physical assault - 50% for MZ, 19% for DZ. Heritability accounts for about 50% of variance in aggression.
Adoption studies - meta analysis showed 41% genetic factors.
The MAOA gene > MAO-A enzyme > regulates serotonin. MAOA-L > low activity of enzyme > higher aggression. Warrior gene - MAOA-L in 56% Maori’s but 31% of Caucasians. Large (28) Dutch family all had the gene.
GxE interaction - MAOA-L only linked to aggression with early trauma in first 15 years (sexual or physical abuse.)
Genetic factors in aggression - AO3
+ Research support - high activity MAOA variant associated with less aggression in male participants, supports link. MAOA-H made less aggressive moves in money distributing game.
C.P MAOA-L participants behaved cooperatively when they knew others were - social norms play a role.
- Complex link - low serotonin leads to aggression but MAOA-L people have higher levels. Levels are disrupted rather than increased.
- Biological determinism issues - criminal gene excuses criminal behaviour and shifts responsibility.
Ethological explanation for aggression - AO1
Ethological - focusing on animals. Adaptive functions of aggression - forces losers into different territories - spreads out resources. Creates dominance hierarchies, which give special status (mating rights.)
Ritualistic aggression - fights between animals rarely result in damage. Encounters consisted of ritualistic signalling. End in appeasement displays - acceptance of defeat. Wolves show neck. Adaptive because losers are not killed but exiled - spread of resources.
IRM - inbuilt physical structures - eg brain circuit - triggers FAP.
FAP - behavioural sequence in response to sign stimulus. Stereotyped, universal, ballistic, single-purpose sequence of behaviours, unaffected by learning.
Stickleback research - fish saw wooden shapes of varying size. They were always aggressive if models had a red spot (supports FAP characteristics - red spot as sign stimulus.)
Ethological explanation for aggression - AO3
+ Research support - aggression is genetic (twin studies) and adaptive. Genetic basis supports it being adaptive and heritable for animals and humans.
C.P different parts of America have differences in aggression - environment as culture overrides innate influences. More reactive aggression in white men in southern states.
- Aggression in animals not always ritualistic - Goodall 4 year chimp war - victims held down and attacked despite appeasement. Systematic killing of rival chimps.
- FAPs not fixed - vary between individuals/situations and modified by experience. Many ethologists prefer ‘modal behaviour pattern.’ E.g. dogs can be trained not to attack.
Evolutionary explanations of human aggression - AO1
Sexual jealousy - greater in males because of threat of cuckoldry, drives aggressive strategies to retain mate to avoid wasting resources. Mate retention strategies - direct guarding (vigilance) and negative inducements (I’ll kms if you leave). Physical aggression more likely when using retention strategies.
Bullying as adaptive - increases reproductive success. Male bullying increases resources and shows dominance to females, which is attractive. Top of dominance hierarchies experience less stress/competition.
Female bullying adaptive because secures fidelity and resources for offspring.
Evolutionary explanations of human aggression - AO3
+ Explains gender differences in aggression - women being physically aggressive would put them and offspring at risk, so they use verbal aggression.
- Cultural differences not predicted - !Kung tribe discouraged from aggression - linked to loss of status. Not universal.
C.P - not actually peaceful - high homicide rate. Observer bias.
+ Real-world application - solutions for bullies in school - giving them roles for status reduces aggressive behaviour as makes up for deficiencies in their life. Prosocial alternatives like captain of sports team.
Dispositional explanation for institutional aggression in prisons - AO1
The importation model - prisoners bring their criminal attitudes and aggressive behaviours into prison. They would be aggressive in any situation.
Prisoner characteristics linked to aggression - prisoners with negative backgrounds (anger, trauma, substance abuse) more likely to be physically aggressive and engage in suicidal activity and sexual misconduct.
Dispositional explanation for institutional aggression in prisons - AO3
+ Research support - no difference in aggression between low- and high-security prisons. (26 and 33 percent). Sample of 561 male inmates with similar criminal history. Inmate characteristics more important.
- Ignores key factors - how prisons run, weak leadership, unofficial rules. Administrative control model suggests that poorly managed prisons more likely to have inmate violence.
- Determinism and free will - prisoners have no control over their dispositions. Aggressive behaviour is inevitable.
Situational explanation for institutional aggression in prisons - AO1
The deprivation model - psychological (freedom and sexual intimacy) and physical (goods and services) deprivation leads to aggression. Worst with unpredictable regimes.
More female staff, African-American and Hispanic inmates, more protective custody and overcrowding predicted aggression in 512 US prisons.
Situational explanation for institutional aggression in prisons - AO3
+ Research support - majority of inmate homicides motivated by prison deprivations e.g. possessions, drugs. Rape very common in prisons due to sexual deprivation.
- Contradictory research - study of Mississippi prisons, conjugal visits not linked to reduced aggression.
C.P - conjugal visits do reduce prison rapes by 80%, according to other research. - Determinism and free will - prisoners have no control over environment. Both dispositional and situational explanations determinist.
Frustration-aggression hypothesis -AO1
Original hypothesis - if a goal is blocked, this creates frustration, which is relieved by aggression. Aggression is displaced onto an innocent target - cathartic. Source of frustration may not be available - abstract, too powerful or unavailable - we displace aggression on weaker alternative.
The weapon hypothesis - frustration alone may not be enough. Students given fake electric shocks gave stronger shocks when guns were present.
Research - students doing jigsaw - impossible or confederate insulted them. Most frustrated students gave the strongest electric shocks.
