Neural And Hormonal Mechanisms In Agression

Question 1

How does seratonin influence aggression ?

Answer 1

Seratonin, in normal levels, exerts a calming, inhibitory effect on neuronal firing in the brain. Seratonin works in the frontal areas of the brain to inhibit the firing of the amygdala, the part of the brain that controls fear, anger etc. However if there is less seratonin in these frontal areas, there is less inhibition. So when the amygdala is stimulated, it becomes more active, causing person to act on impulses, making aggression more likely.

Question 2

What did Mann et al. do with regards to neural mechanisms ?

Answer 2

Administrated the drug dexfenfluramine (depleted seratonin in the brain) to 35 healthy adults. Researchers used a questionnaire to assess hostility and aggression levels, which rose following administration ( not among females )

Question 3

What did Scerbo and Raine do ?

Answer 3

Meta analysis of 29 studies that had examined seratonin levels in antisocial adults and children. These studies consistently found lower levels of seratonin than normal in these individuals. E.g. Attempted suicide.

Question 4

Who took blood samples from 80 dogs referred to as aggressive to humans, and compared their blood with non- aggressive dogs. Aggressive dogs averaged 278 units of seratonin, while non aggressive dogs averaged 387 units of seratonin ? ?

Answer 4

Rosado et al.

Question 5

What did brown at al do ?

Answer 5

Metabolite levels- the major metabolite (waste product) of seratonin tends to be low in the cerebrospinal fluid of people who display aggressive behaviour. The lack of waste products associated with the breakdown of seratonin is an indirect indication of low levels of seratonin in many aggressive individuals

Question 6

What did couppis at al do ?

Answer 6

Suggests that the brains sees aggression as a reward, whenever we perform an activity we find rewarding, e.g (sex, eating or recreational drugs) , brain releases higher levels of dopamine. When this dopamine attached itself to receptors in the brain, it created a pleasure circuit, which individual funds reinforcing. Person this motivated to repeat actions that led to an increase in dopamine; may make aggressive behaviour more frequent.

Question 7

Increased rates if violence are sometimes found in schizophrenics, usually when patient is severely delusional, resists raking their medication and has a past history of violence. As a result, antipsychotics have been used effectively in decreasing violence in both psychotic and non-psychotic patients - who found this ??

Answer 7

Glazer and Dickson

Question 8

Cherek et al did what ?

Answer 8

Amphetamines raise levels of dopamine. Administrated either amphetamines or caffeine to participants in a competitive lab task, and found amphetamines raised frequency of interpersonal hostility while caffeine reduced it

Question 9

… Measured dopamine levels in the prefrontal cortex of rats before, during and after a confrontation with another rat. Found significant increase in dopamine levels over baseline levels after the confrontation, suggesting dopamine levels are not a cause of aggression, but a response to it ?!?

Answer 9

Erp and Miczek (2000)

Question 10

Give a alternative explanation for seratonin yoooo

Answer 10

Aggression is not caused by low levels of seratonin but by low seratonin metabolism, if presynaptic neurons do not release enough neurotransmitter into the synapse, then there’s a corresponding increase in the number of post-synaptic receptors to compensate for this deficiency. .. Suicide completes- increased no. Of seratonin receptors in prefrontal cortex had more violent methods of suicide Mann et al,

Question 11

What did booij et al. do ?

Answer 11

Longitudinal following individuals throughout childhood into adulthood; measured aggression through parental and self reports an seratonin synthesis through PET scans. Aggressive children= low seratonin but by time these children reached adulthood, showed no difference despite fact seratonin levels remained low.

Question 12

Alcohol consumption caused major disturbances in the metabolism of brain seratonin, depleting levels in the brains of normal individuals. In susceptible individuals, this can lead to aggressive behaviour in response to environmental or psychological stimuli ……. Who found this ?? :)

Answer 12

Badawy (2006)

Question 13

What did Ferrari et al. (2003) do ? ;)

Answer 13

Allow a rat to fight with another rat at a specific time every day for 10 days . On the 11th day, rat was not allowed to fight but researchers measured the levels if dopamine and seratonin in the rats brain. In anticipation of the imminent fight, the rats dopamine levels had increased and seratonin decreased, even though didn’t fight. Shows experience had changed the rats brain chemistry, altering it in ways that would be consistent with the onset of aggressive behaviour.

Question 14

What did couppis do in terms of micey mice ?

Answer 14

Studying the link between dopamine and aggressive behaviour, couppis turning off dopamine from mices brain. However dopamine also plays an important role in coordination and so the decrease in aggression could be due to it being less aggressive or simply that the animal finds it difficult to move.

Question 15

What’s the relevance of bandits in evaluating neural explanation ?

Answer 15

So I’ll learning theory can be a powerful influence on the aggressive behaviour of children.

Question 16

What’s the relevance of zimbardo et al when evaluating the neural explanation ?

Answer 16

Deindividuation can increase aggressive behaviour in particular situations where personal responsibility is diminished. We can’t underestimate the complexity of human aggression. Insufficient on it’s own to explain aggressive behaviour.

Question 17

In terms of real world application , why is the neural explanation good ?

Answer 17

Ghaziuddin and Alessi found administration of antidepressant trazodone produced a notable improved to in about half children treated for being aggressive. Selective groups - dementia and aggressive children…. SSRI.

Question 18

What is testosterone ?

How do levels of testosterone change as age does ?

Answer 18

One of the androgen hormones - so clawed because they produce male characteristics (which is why aggression is seen as more of a male characteristic)
Reaches a peak in young adult males and typically these levels gradually decline with age.

Question 19

What is the nature of the link between testosterone and aggression ?

Answer 19

Not a simple cause and effect mechanism. Rather, the action of testosterone on brain areas involved in controlling aggression makes it more likely that a particular behaviour will be displayed.

Question 20

Who did a meta analysis of five studies involving 230 male adults and found a low positive correlation between levels of testosterone and aggression?

Answer 20

Archer (1991)

Question 21

What did book et al. (2001) do and find ?

Answer 21

Average correlation of +0.14 between testosterone and aggression
Meta analysis of 45 studies.

Question 22

What did Olweus et al. 1988 do ? And find ?

Answer 22

Compared samples of delinquent and non delinquent male students. Found higher levels of testosterone in the delinquent sample, although this was not statistically significant.

Delinquents with a history of violent offences also had higher levels of testosterone than those with a history of non violent offences.

Question 23

Where does strong evidence for the role of testosterone influencing aggression come from ?

Answer 23

Edwards 1969 - animals ; castration. The removal of testosterone has found that in general it leads to decrease in aggression in animals whilst replacement if testosterone restores the behaviour.

Question 24

What is the challenge hypothesis ?

Answer 24

Wingfield et al. - in monogamous species, testosterone levels should only rise above a baseline in response to social challenges such as male male aggression. According to this explanation therefore, competitive encounters between young would lead to a surge in testosterone levels.

Question 25

Who claimed that there is a link between aggression and the hormone cortisol?

What type of relationship do they believe exists ?

Answer 25

Van Goozen et al. - relationship is an inverse correlation , lower levels of cortisol are associated with higher levels of aggressive behaviour.

Question 26

What is an alternative explanation of the link between cortisol and aggression ? -ANS

Answer 26

Aggressive behaviour becomes an attempt to create a stressful situation in order to provoke ANS activation and cortisol release - so low cortisol levels is experienced as being aversive

Question 27

What effect does cortisol appear to have on aggression related hormones such as testosterone ?

Answer 27

Important mediating influence by inhibiting the likelihood of aggressive behaviour.

Question 28

What study found a significant positive relationship between testosterone and aggression, but only in individuals with low cortisol levels. ? Relationship did not exist in participants with high cortisol levels ….

Answer 28

Popma et al. (2006)

Question 29

What did Virkunnen find in antisocial adults ?

What does this this suggest ?

Answer 29

Antisocial adults tend to have low resting rates of cortisol. In particular, he found that offenders with antisocial personality disorder and a habitually violent tendency had lower levels than individuals with antisocial personality disorder who displayed aggressive behaviour only occasionally .

Question 30

What did Fairchild and Goodyer discover ?

Answer 30

Males who display antisocial behaviours such as aggression tend to have significantly lower levels of cortisol than their better behaved peers.

They compared cortisol levels of both groups in a neutral setting and a stressful situation.

Antisocial cortisol lowered significantly and vice versa.
This resulted in an inability to inhibit inappropriate responses to the stressful situation, including aggression.

Question 31

Who did a study of conduct disorder ?

And what did he find ?

Answer 31

Reinecke(2011)examined cortisol levels in preschool children to see if they predicted concurrent and later aggression.
Basal cortisol levels were measured in saliva samples and reactive cortisol collected over the course of a series of challenging tasks.
Teachers provided ratings of a later child aggression. Lower basal cortisol levels predicted higher levels of aggression in kindergarten a year later. Among kindergarten children, lowered levels of cortisol during the challenging tasks were associated with higher aggression ratings.

Question 32

Name the two studies that when put together suggest an inconsistent testosterone-aggression link

Answer 32

Archer - high testosterone correlate high aggression.
Bain et al. No such relationship . Found no significant different in testosterone levels between men who had been charged with murder or violent assault and men who had been charged with non-violent crimes such as burglary.

Question 33

What is a problem with most of the studies showing an aggression testosterone link ?

Answer 33

They have relatively small sample sizes subjective to men in prisons , using either self report or measures of aggression that are assumed from the type or severity of the crime involved.

Question 34

Aggression or dominance ?

Study and shit ?

Answer 34

Mazur (1985) - we should distinguish between aggression and Dominance ( having status over or controlling other individuals)
Mazur claims that aggression is only one form of dominance behaviour and that the influence of testosterone on dominance may be evident in more subtle ways that do not include aggression.
This may well explain why some studies find a positive association between testosterone and aggression whereas others do not.

Question 35

Who argued that testosterone in fact has positive effects on people ?

Three people ;)

Answer 35

Zitzmann - testosterone supplements have been shown to increase vigour and energy in older males and lower levels of testosterone linked in with depression in older males (Barrett Conor et al.)
McNickolas et al. - study of 208 men, increases in positive mood and decreases in negative were confirmed during testosterone replacement therapy.
Davis found testosterone important in maintaining a woman’s energy levels and sense of wellbeing, regardless of age .