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10 Cards in this Set
- Front
- Back
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Neurotransmitter Serotonin AO1 |
Serotonin, in normal levels, exerts a calming, inhibitory effect on neuronal firing in the pre-frontal cortex AND the amygdala, the part of the brain that controls emotional responses.
Low levels of serotonin prevent this inhibitory effect, with the consequence that individuals are less able to control their impulsive and potentially aggressive behaviour.
As a result when the amygdala is stimulated by potentially threatening events it becomes more active, causing the person to be more impulsive and making aggression more likely.
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Neurotransmitter Serotonin AO2 |
+ Rosado (2010) took blood samples from 80 dogs referred to veterinary hospitals because of their aggression levels. These dogs averaged 278 serotonin units when compared to non-aggressive dogs, who averaged 387 serotonin units. + Mann (1990) found those 35 people given dexfenfluramine (a drug known to deplete serotonin) demonstrated an increase in aggression and hostility scores amongst male participants.
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Neurotransmitter Serotonin AO2 |
-Booij (2010) showed that children who had lower levels of serotonin were more likely to demonstrate aggression, but by the time they reached adulthood there was no difference in aggression between the previously aggressive children and ‘controls’. Booij believes that psychological factors that develop with age may help to buffer these individuals from the increased risk of aggression that their low levels of serotonin poses.
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Neurotransmitter Dopamine AO1& AO2 |
Dopamine is released in the brain when we participate in an activity that is rewarding. If the brain releases dopamine when aggression is occurring, the individual is motivated to repeat the aggressive action in order to repeat the release of dopamine, creating a pleasure circuit.
•van Erp & Miczek (2000) found higher rates of dopamine in male rats following ‘confrontations’.
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Neurotransmitters IDAs & AO2 |
?Research such as Rosado, relies on using NHAs. Although this is done for obvious ethical reasons, it does pose two problems. Firstly cna we really generalise from the aggression of dogs to the aggression of humans? Secondly, if we are similar enough to generalise from NHAs to humans, then surely NHAs deserve similar ethical safeguards awarded to humans?
Are the findings seen in Mann's research really that valid? Mann only assessed the hostility ratings, is this the same as aggression? Someone might be hostile, but their hostile feelings may never become aggressive.
Neurotransmitter evidence clearly offers a valuable 'treatment' for aggressive behaviour. In the real world, using antidepressants that increase serotonin offers a valuable treatment of aggression – Bond (2005) notes ADs reduced irritability levels.
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Hormones Testosterone AO1 |
Testosterone is an androgen hormone, they produce male characteristics. Levels of testosterone reach a peak in young adult males and typically decline with age. The ‘Challenge hypothesis’ proposed by Wingfield (1990) suggests that testosterone levels should only rise in response to social challenges or threats to a male’s status.
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Hormones Testosterone AO2 |
+ Edwards (1969) reported that castration led to a decrease in aggression in animals, but when supplemented with testosterone, aggressive behaviours increased again. +Book (2001) conducted a meta-analysis of 45 studies and came up with a correlation of +0.14 between testosterone and aggression. -Bain (1987) found no significant difference in testosterone levels of violent criminals and those criminals charged with non-violent offences.
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Hormones Cortisol AO1&AO2 |
Cortisol is thought to have a mediating influence on other hormones such as testosterone. Therefore low levels of cortisol are inversely correlated with high levels of aggression. + Popma (2006) found a positive relationship between aggression and testosterone, but only in those participants who also had low cortisol levels. A positive relationship didn’t exist in those who had normal or high levels of cortisol.
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Hormones IDAs & AO2 |
?Most Testosterone research is conducted on all-male sample groups. However research conducted on females suggests that those females high in testosterone tended to be more assertive and status seeking. Perhaps aggression is the status seeking behaviour that men demonstrate because that is what they've been socialised to do?
?It is assumed by hormonal explanations that hormones are the CAUSE and aggression is the EFFECT. However, Klinesmith (2006) found that testosterone levels increased in those participants allowed to handle a gun for 15 minutes, compared to participants assigned to play with a toy. This clearly demonstrates how situational factors, such as the presence of weapons may increase hormones. So hormones may not be the causal factor in aggression? |
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Neural AND Hormonal CONCLUSION |
? Although it is an advantage that both neural and hormonal mechanisms can offer us a seemingly straightforward explanation of aggression. Are these explanations too reductionist? They completely ignore both social and cognitive factors which we know are significant influences on aggressive behaviour.
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