Aggression Flashcards
what enzyme does the MAOA gene code for and what does this enzyme regulate?
MAOA enzyme
controls metabolism of seretonin
what are the 2 variations of MAOA gene- what does the low activity one lead to?
MAOA-H and MAOA- L
-MAOA-L leads to abnormal activity of MAOA enzyme= abnormal seretonin levels= abnormal seretonin is asssociated with aggression
what were findings of dutch family study?
male members behaved in violent manner and most had been involved in serious crime. These men were found to have abnormal levels of MAOA enzyme, thus low serotonin levels (they had the MAOA-L gene). Was passed on from X chromosome of mothers.
why does the effect of the MAOA-L gene only affect males?
-The problem only affects males as they only have one X chromosome. Women don’t show these traits as they have second X chromosome carrying good copy of gene.
why are gene influences on aggression socially sensitive (jail sentence reduced)?
suggests no freewill over our behavior- leads to implications for crime and punishment
- In 2007, a man admitted to stabbing & killing a man & received sentence of just over 9 years. However, an appeal court judge in Italy, cut the sentence by a year after finding out he had genes linked to aggression.
how does evidence from twin study support that genes dont 100% influence aggression?
mz twins share 100% of genes, thus if mz twins are more alike in aggressive behaviour then it is due to genes not environment. O’connor- concordance rates for aggression among mz= 72% whereas 42% for dz (reared together) suggests genes have role as mz % is higher than dz but not 100% genes.
Why does research findings into genes causing aggression vary?
meta-analysis of 51 twin and adoption studies found that self-report studies found higher genetic influence than studies which used parent/teacher reports. Thus, difficult to draw valid conclusions about the role of genetic factors.
what is the role of the amygdala and where is it located?
part of limbic system- involved in emotion, how we respond to threats
One on each side of brain in temp lobes
Over-activity= linked to aggression
what is the role of the PFC and where is it located?
In frontal lobes, connected to limbic system
Involved in planning and moderating behaviour
Regulate amygdala emotional responses to maintain emotional control
Damage to pfc= loss of control
what is the role of seretonin and where is it located?
Inhibits amygdala
Low serotonin= no inhibitory effect= less control of aggression
Serotonin deficiency hypothesis
4 evaluation points of neural explanation (reduction, support for each function)
+: support for role of amygdala- Whitman killed 14 people in mass university shooting. He left suicide note asking for autopsy, to see if there was biological reason for his actions. Found tumour pressing on amygdala
+: support role of prefrontal cortex- Raine et.al PET scan of 41 murderers. Found reduced glucose metabolism in pfc. Damage to pfc= increased aggression
+: support for role of seretonin- meta-analysis found neg. Correlation between seretonin levels and aggression. (low serotonin= higher aggression). However, strength of correlation differed when self-report was used compared to others reporting aggression
-: reductionist- reduces aggression to function of brain structures ignoring nurture and SLT. Aggression is likely to be combination of both (diathesis stress model)
how is testosterone linked to aggresssion?
Aggression increases with increased levels of testosterone during puberty. In animals, when mice are castrated aggression decreases
what are ethical issues of carrying out hormone research on humans?
Androgens can’t be administered to humans to see if changes in aggression occur as they would need to be administered over a period of time, which carries a health risk
describe dabbs study investigating relationship between T and crime and prison?
Measured testosterone in saliva in 692 adult male prisoners and found positive relationship between level of violence and in a crime and levels of testosterone. Those thta have comitted more crimes involving sex and violence and broke more prison rules had higher testosterone levels than inmates that comitted crimes such as burglury and theft
4 evaluation points of hormones influencing aggression? (gender bias, correlational, determinism, reductionism)
Androcentric- work carried out on males. Effects of testootserone are said to be the same for males and females. Dabbs looked at testosterone of 84 female prisoners. Found testosterone levels were related to criminal violence. Testosterone highest in unprovoked violence and lowest in cases of defensive violence
It could be that aggression causes testosterone to increase instead of testosterone causing aggression to increase. Research shows this could be the case in status conflicts. Testosterone increases in winners and declines in losers, thus testosterone responds to behaviour as well as causes behaviour
Argues aggression is determined by levels of hormones. Socially sensitive as it led to some suggesting chemical castration reduces aggression. High levels of testosterone linked to aggression, thus castrating males should reduce aggression, however there could be other factors causing aggresssion
Reduces complex human behaviour of aggression down to testosterone. Emphasises role of nature and ignores theorys such as SLT. Diathesis stress model may be better explanation
what is emotional and sexual jealousy?
Emotional jealousy- when someone is jealous of an emotional connection their partner has with someone else (trust)
Sexual jealousy- someone is jealous of a sexual/ potentially sexual relationship their partner has with someone else
what is sexual infedelety and direct guarding?
Sexual infedelity is a cue that triggers sexual jealousy causing them to become aggressive and prevent their partner from ‘straying’. This helps a man protect his genes, ensuring his resources will be put into his offspring.
Direct guarding- when male is vigilant over partner’s behaviour. This is linked to violence. Women who reported this behaviour were twice as likely to suffer phys. Violence
2 eveluation points of sexual/ emotional jealousy? (supporting research)
+: supporting research- Young (1978) asked students to describe reactions to a jealousy inducing situation shown in film where someone else chats up their partner in front of them. Men= respond angrily and become drunk and threaten their rival. Women= pretending not to care or trying to increase their attractiveness to regain the attention of male. Thus, sexual jealousy triggers aggression in males.
+: supporting research- study of abused women living at women’s refuge, two thirds reported their husbands were jealous. Another study investigated 100 cases of spousal violence. In majority of cases husbands reported frustration over inability to control their wives with accusations of infidelity the most common complaint. Therefore, this shows that sexual jealousy triggers aggression in males. Although sexual jealousy may be the prime motive, alcohol and drug abuse, along with low socio-economic status, all correlate highly with abuse of a spouse.
what is warfare?
formation of coalitions to attack others within the same species. Intelligent species opt for this as it may lead to injury or death.
Success may lead to the male be more attractive, increasing reproductive success, thus increasing genetic line
2 evaluation points of warfare? (supporting evidence/ reductionist)
+: Supporting evidence- aggression is innate comes from universal nature of warfare worldwide. Many hunter-gatherer tribes fight for food, women and status. Research found a correlation between killing & reproduction. Males who killed the most men had 2x as many wives and 3x as many children as non-killers. suggest that the aggression of men is a product of evolution to increase reproductive success.
-: reductionist- reduces aggression to evolutionary instincts and the passing on of genes therefore focusing on nature. Many argue that evolutionary explanations neglect social factors. In reality, instincts will be modified by culture.
what is ethology and what are benefits of aggression for resources/ status?
Ethology- Study of animal’s behaviour in natural environment. Ethologists state aggression is innate instinct triggered by releasers.
Aggression helps animals survive via distribution of resources; aggression can also help establish dominance in hierarchies
Ethologists argue animal findings can be genralised to humans as dominance in humans brings about benefits of power/ access to resources
what is IRM and FAP?
IRM- In built psychological process (network of neurons in brain)
Env. Stimulus triggers IRM which causes specific sequence of behaviours (FAP)
what are 3 characteristics of FAP?
Ballistic- FAP’s can’t be changed/ stopped
Stereotyped- behaviour always occurs in same way
Univeral- found in every individual species
what is the procedure and findings of the 3 spined stickleback experiment?
Researcher presented fish with 3 different wooden models of different shapes and 2/3 had red under-belly.
Found that regardless of shape, if the wooden model had red under-belly the fish would display aggressive behaviour