Aggression Flashcards
(28 cards)
What is the limbic system associated with?
The regulation of emotions and emotional behaviour.
What is the role of the amygdala thought to be?
Regulating emotional behaviour
Gospic et al (the Ultimatum game)
Found that when participants rejected an unfair monetary reward (social provocation) there was an increase in amygdala activity on the fMRI scan. There was a less drastic increase when benzodiazepines were used suggesting a link between the amygdala and aggression
What is the role of serotonin in aggression?
Serotonin is associated with the regulation of impulsive behaviour when present at normal concentrations in the orbitofrontal cortex. Due to the link between serotonin and the regulation of emotional impulsive behaviour it has been proposed that it is involved in controlling sleeping patterns, due to being found in lower levels in non violent offenders
A03: 1 weakness 1 strength
Neural and Hormonal mechanism in aggression
Weakness: there may be an over reliance on the limbic system as an explanation for aggressive behaviour. The OFC may also play a role due to its link with the action of serotonin therefore, it may be more effective to focus on the neural connections between the OFC and the limbic system instead of looking at the two in isolation
Strength: Evidence supporting the negative correlation between increasing serotonin levels and decreasing levels of aggression. Researchers found that ppt who were given the serotonin agonist “paroxetine” behaved less aggressively to the control group whilst playing a video game.
Role of testosterone in aggression
Testosterone= male sex hormone secreted from the pineal gland & responsible for male facial characteristics + reproductive organs.
May be a link between decreased testosterone and decreased levels of aggressive behaviour, a positive correlation demonstrated by castration studies.
Dolan et al on testosterone affects on aggression
Found that violent prisoners displayed higher levels of testosterone than their non violent counterparts
1 weakness for the role of testosterone
Through the dual hormone hypothesis, testosterone doesnt work alone in determining aggression, but rather has a relationship with the stress hormone cortisol, where increased levels of aggression are associated with increased testosterone levels but only when cortisol is low. Different hormones have different predictive values for aggression and are part of a system that develops aggressive behaviour
1 study for genetic factors in aggression
Coccaro et al:
Found concordance rates of 50% for MZ twins and 19% for DZ twins in terms of physical aggression. This strongly suggests a genetic basis for aggression.
How does the candidate gene MAOA cause aggressive behaviour?
Codes for the MAOA enzyme that breaks down serotonin within the synaptic cleft after neurotransmission eg leading to increased levels of metabolite 5-H1AA.
Evidence for role of MAOA gene
Brunner et al:
Provided evidence for the link between decreased MAOA levels and aggression in a Dutch family who were all actively engaged in aggressive behaviour, they all had low MAOA levels.
Frazzetto et al on the role of the MAOA gene
More beneficial to take an interactionist approach. Researchers found low MAOA levels only resulted in increased aggression when accompanied by traumatic childhood events (before 15). Supports the diathesis stress model where the biological vulnerability (diathesis) is the genetic mutation of the MAOA gene and the stressor is child abuse.
A03: 1 weakness
MAOA gene
Weakness: diathesis stress model makes it hard to distinguish the effects of nature and nurture. McDermott et al found that provocation in a money lending game was key to triggering aggressive behaviour in individuals with low MAOA activity levels, whereas previously they displayed the same levels of aggression as the healthy, neurotypical control group. Lack of clarity over the role of the stressor.
A03: 2 strengths
Strength: positive correlation between increasing MAOA activity levels and increasing levels of pro social behaviour, found ppts with high MAOA activity levels behaved more compassionately in a money lending game often with fewer provocations or refusal of offers. Suggests link is valid because theres correlations in both directions
Strength: Strong link between MAOA activity levels and concentrations of serotonin. Based on animal studies where researchers are able to prevent the expression of the gene coding for the MAOA enzyme, thus allowing the researchers to study its effects in isolation.
Define the ethnological explanation of aggression
Aggression increases the chance of survival of a species, through appeasement following an aggressive confrontation, the “loser” will seek out new territory, increasing resources of the species and increasing chances of survival.
Aggression acts as a method of increasing social status, researchers found young children use aggressive tactics in playgrounds to assert authority and lead others to have their way.
What are ritualistic behaviours?
Ritualistic behaviours are a series of behaviours conducted in the same, set order. After an aggressive confrontation, the loser will make themselves vulnerable to the victor (wolves display their neck) as a sign of accepting defeat. This is adaptive as it ensures no further aggressive behaviour between the two, thus increasing the likelihood of survival of the species.
What is the physiological process of an innate releasing mechanism?
The innate releasing mechanism is activated by a release signal causing a series of behaviours, a fixed action pattern. Eg, being responsive to a releaser which is ballistic, single purpose, unaffected by learning, universal & stereotyped. A releaser which activates the IRM will always lead to the FAP, no further signals needed. This is an innate response and cannot be unlearnt. Researchers found that male sticklebacks will respond aggressively to model red spots (a releaser to trigger the IRM) regardless of whether the model resembles a stickleback or not.
2 strengths of the ethnological explanation of aggression
Strength: Goodall, observed chimpanzees & found that rival communities slaughtered eachother systematically, despite appeasement and ritualistic signals displayed by the victims. This supports the idea that once a releaser has triggered the IRM, this will always lead to a FAP and so the releaser is a stronger predictor of aggressive behaviour than appeasement.
Evolutionary explanations: Sexual jealousy
Sexual jealousy is stronger in males due to “paternity uncertainty” which may lead to cuckoldry i.e a male raising a child that is not his own. This is an evolutionary disadvantage, due to the male wasting his resources which he could otherwise use on his own offspring.
Outline male retention strategies
- Behaviours that are adaptive in reducing the risk of cuckoldry.
2 types: direct guarding & negative inducements
Direct guarding= insisting on knowing where the partner is and who they are with
Negative inducements= threats of suicide to avoid infidelity
Support for the existence of male retention strategies: Shackleford et al
Found 107 couples, who’d been marries for less than a year individually completed the male retention inventory (for husbands) and the spouse influence report (wives), there was a positive correlation between increasing scores and these 2 measures which translated to being an important predictor of the use of aggression in such married relationships.
Other researchers found that male retention strategies left 53% of respondents fearing for their lives.
How does male bullying have an evolutionary advantage?
Men who bullied other men through reinforcing a power imbalance, were more likely to have their pick of resources and to mate with more females (due to the influence of fewer competing males) and increasing the likelihood of their genes being passed onto as many offspring as possible.
Female bullying
Likely to occur within relationships to ensure fidelity (through threats or monitoring) as opposed to aiming to acquire new relationships (which is the male perspective) therefore the aggressive act of bullying may be considered as adaptive.
1 strength for the evolutionary explanation of aggression
- Provides an explanation for gender differences in aggression. Suggests females are more likely to engage in acts of verbal, as opposed to physical, aggression as this ensures that their own survival, as well as the survival of their offspring, is not endangered. Such tactics also prevent females from being involved in life threatening physical confrontations with their partners and so further increases their chance of survival through the use of non aggressive methods of resolving conflicts.
