Aggression Flashcards
Neural and hormonal mechanisms
The limbic system
Network of structures in the brain (including the amygdala and hypothalamus) which are thought to be closely involved in regulating emotional behaviour including aggression
Neural and hormonal mechanisms
Serotonin
Neurotransmitter with widespread inhibitory effects throughout the brain. Normal levels in the orbitofrontal cortex are linked with reduced neuron firing, which leads to greater control. If serotonin decreases and disrupts this mechanism, levels of impulsive behaviour including aggression will increase.
Neural and hormonal mechanisms
Testosterone
Hormone from the androgen group that regulates social behaviour by its influence on certain areas of the brain. There is a positive correlation between testosterone levels and aggressive behaviour (Dolan et al).
Neural and hormonal mechanisms
Negatives
Studies suggest the amygdala functions with the orbitofrontal cortex, which isn’t in the limbic system. The OFC is thought to be involved in self-control, impulse regulation and inhibition of aggressive behaviour. Emil Coccaro et al stated that in patients with psychiatric disorders featuring aggression, activity of the OFC is reduced, disrupting its impulsive control function which increases aggression. This combined with the findings of Gospic et al shows regulation of aggression is highly complex and involves at least 3 neural structures: amygdala, OFC and the connection between the two.
Genetic factors
Twin studies
Suggest heritability accounts for about 50% of the variance in aggressive behaviour. Coccaro et al studied MZ and DZ twins for aggressive behaviour. They found concordance rates for direct physical assault were 50% for MZ twins and 19% for DZ twins. For verbal aggression the figures were 28% and 7%.
Genetic factors
Adoption studies
Similarities in aggressive behaviour between an adopted child and their biological parents suggests genetic factors are operating. Rhee and Waldman carried out a meta-analysis of adoption studies of direct aggression and antisocial behaviour. They found genetic influences accounted for 41% of the variance in aggression, in line with the results of twin studies.
Genetic factors
The MAOA gene
Monoamine oxidase is an enzyme which breaks down neurotransmitters. The production of this enzyme is determined by the MAOA gene. A dysfunction in the operation of this gene can lead to abnormal activity of the MAOA enzyme which will affect serotonin levels. Brunner et al studied 28 males involved in aggressive violent criminal behaviours. They found these men had abnormally low levels of MAOA in their brains and the low activity version of the gene. Gregory Stuart et al studied 97 men who were part of a batterer treatment programme due to inflicting IPV. Men with the low activity MAOA gene were the most violent. They engaged in the highest levels of physical and psychological aggression and inflicted the worst injuries on their partners.
Genetic factors
Negatives
Likely that other genes involved. Shown in the study by Stuart et al. IPV in men was associated with the serotonin transporter gene which influences serotonin activity in the brain, as well as being associated with low MAOA activity. The combination of these two factors lead to the development of more aggressive behaviours, supporting the fact that the MAOA gene isn’t a full genetic explanation.
The ethological explanation
Adaptive functions
Beneficial to survival because when members of the species are forced to establish new territory they spread out over a wider area which reduces competition pressure and the possibility of starvation. Also establishes dominance hierarchies, which is adaptive as dominance over others brings benefits such as the power to get your own way and resources.
The ethological explanation
Ritualistic aggression
Aggressive encounters usually consist of periods of ritualistic signalling, not physical damage (Lorenz). Confrontations end with ritual appeasement displays, which indicate acceptance of defeat and inhibit aggressive behaviour.
The ethological explanation
IRPs and FAPs
IRMs are built in physiological processes or structures in the brain. Environmental stimuli trigger the IRM which releases a specific sequence of behaviours (a FAP). FAPs have 6 features: universal, stereotyped, unaffected by learning, ballistic, single purpose and a response to an identifiable specific sign stimulus.
The ethological explanation
Positives
Evidence supports the idea that aggression is an innate behaviour. Brunner et al showed the low activity variant of the MAOA gene is closely associated with aggression in humans, which suggests an innate basis for aggression. There is also evidence that activity in the limbic system can trigger aggressive behaviour in humans and other animals. This supports the validity of the ethological explanation because the studies suggest a genetic and physiological basis of aggression.
The ethological explanation
Negatives
Evidence against ritualistic aggression. Goodall observed chimpanzees which demonstrated behaviour against the view that aggression is relatively physically harmless. Male chimps from one community set about systematically slaughtering all the members of another group. This was done in a coordinated and premediated way. Sometimes a victim was held down to be hit and bit in an attack lasting up to 20 minutes. The violence wasn’t inhibited despite signals of appeasement and defencelessness.
Evolutionary explanations
Sexual jealousy
Male never be sure if they fathered a child. Paternal uncertainty is a result of the threat of male cuckoldry, or having to raise offspring that are not his own. This wastes resources and doesn’t aid survival of the father’s genes. Men in evolutionary past who avoided cuckoldry reproduced more successfully, so psychological mechanisms evolved in men which increase anti-cuckoldry behaviours. Eg. sexual jealousy leads to the use of aggressive strategies to retain partners.
Evolutionary explanations
Mate retention strategies
Wilson & Daly Direct guarding (male vigilance over partner’s behaviour) Negative inducements (threats of dire consequences for infidelity)
Evolutionary explanations
Intimate partner violence
Shackelford et al
Strong positive correlation found between men’s reports of mate retention behaviours ams women’s reports of their partner’s physical violence. Men who used guarding or negative inducements were more likely to use physical violence.
Evolutionary explanations
bullying
Bullying occurs due to a power imbalance. Evolutionary ancestors used bullying as an adaptive strategy to increase survival chances by promoting health. Volk et al argue characteristics of bullying are attractive, suggesting strength, dominance and acquisition of resources in males. it also wards off potential rivals. These characteristics therefore increase access to females and decrease chances of threat from competing males. This makes the behaviour naturally selected as it increases rate of reproduction. Female bullying usually occurs in relationships to control a partner. Women use bullying behaviour to secure their partner’s fidelity and ensure they continue providing for their offspring.
Evolutionary explanations
Positives
accounts for gender differences. Males often engage in more aggressive behaviours than females. Campbell argued a female with offspring is less likely to be aggressive as it would endanger the survival of her and he offspring. it is more adaptive for females to use verbal aggression to retain a partner who provides resources, and to avoid physical aggression which can be life threatening.
Evolutionary explanations
Negatives
methodological issues. extremely difficult to test hypotheses about the evolution of behaviours to solve problems of adaptation in our evolutionary past. Most research is therefore correlational, for example finding associations between mate retention behaviours and aggression. It doesn’t allow us to draw cause and effect conclusions.
Frustration-aggression hypothesis
Frustration always leads to aggression, and aggression is always the result of frustration (Dollard). based on the psychodynamic concept of catharsis, and views aggression as a psychological drive. If attempts to reach a goal are blocked by external factors we experience frustration. This creates an aggressive drive which leads to aggressive behaviour. Aggression isn’t always directed to the source of frustration because: the cause may be abstract, too powerful and hold a risk of punishment, or unavailable at the time. The aggression is displaced onto an alternative.
