Aggression- A03

Question 1

neural and hormonal mechanisms

The amygaldas role in aggression is backed up by research

Answer 1

• Pardini carried out a longitudinal study of 56 male pps
• MRI scans showed that those with lower amygalda volumes had higher levels of aggression & violence
• This suggests that the lower amygalda plays a key role in evaluating the importance of sensory information and that lower amygalda volume compromises this ability,, making a violent response more likely

Question 2

neural and hormonal mechanisms

The role of the hippocampus in aggression is supported by MRI scans of hippocampus asymmetry

Answer 2

• Reine et al studied 2 groups of violent criminals.
• ones that faced conviction (unsuccessful psychopaths)
• others who had evaded the law (successful psychopaths)
• The latter group were considered to be cold, calculating criminals
• The former acted more impulsively
• MRI scans revealed asymmetries in the hippocampus (part of limbic system) in the ‘unsuccessful group’ an imbalance presumed to have arisen early in brain development
• The researchers suggested this asymmetry might impair the ability of the hippocampus and the amygalda to work together so that emotional information is not processed correctly leading to inappropriate verbal & physical responses

Question 3

neural and hormonal mechanisms
The issue of cause & effect affects out understanding of the difference between neural & hormonal difference & aggression.

Answer 3

• most research into neural & hormonal influences on aggression is correlational due to ethical reasons (opportunities to experimentally manipulate brain structures & hormones are limited)
• When two variables are correlated it is impossible to establish which one is the cause of the other, or if a 3rd variable is involved
• this risks oversimplifying other factors e.g serotonin & aggression as other factors which may influence aggression are overlooked
• there is no alternative without tasing ethical issues. Many researchers consider research w/ non human animals ethically acceptable e.g castration of male rats but this raises generalisability

Question 4

neural and hormonal mechanisms

There is some support for the serotonin deficiency hypothesis to explain human & non human aggression

Answer 4

• Rosado compared a sample of 80 dogs of various breeds that had been referred to Spanish veterinary hospitals for their aggressive behaviour
• Control sample of 19 dogs that didn’t show aggressive behaviour
• Aggressive dogs averaged 278 units of serotonin
• Non aggressive averaged 387 units
• Duke et al: meta-analysis of 175 studies found an inverse relationship between serotonin levels & aggression i.e lower serotonin, higher the aggression
• suggests serotonin could be a casual factor in aggression

Question 5

neural and hormonal mechanisms
However the role of testosterone in aggression has been challenged by studies failing to show a relationship between it & human aggression

Answer 5

• e.g some research has shown no correlation between testosterone & actual violence in male prison inmates
• the ones that have found a relationship often involve a small prison sample of men, using self report or rating of aggression based on their crime
• Mazur suggests testosterone may actually promote status-where aggression is just one type. Some seek status through the use of aggression whilst others through wealth
• suggests the relationship between testosterone & aggression may be more complex than once thought

Question 6

Genetic factors in aggression

It is also possible that the MAOA gene can explain gender differences in aggression

Answer 6

• offers explanation for uneven rates of violence between males & females
• Niehoff suggests that this may be a consequence of the different vulnerabilities
• MAOA gene : linked to X chromosome
• Women have 2 X chromosomes- men only have 1
• Men more likely to be affected ( e.g when they inherit an X linked gene from their parent ) wheras women second X chromosome may over ride it & expression of the abnormal MAOA gene is prevented
• women unaffected as they have 2 X chromosomes with a ‘normal gene’

Question 7

Genetic factors in aggression

The role of the MAOA gene in serious violent behaviour is supported by evidence

Answer 7

• Tiihonen found that the MAOA-L in combination with another gene was only found in extremely violent prisoners & not offenders
• This gene combination may make it difficult for a person to control their violent urges & therefore show that the MAOA gene does play a role in violence but that other genes as well as environmental factors are also implicated

Question 8

Genetic factors in aggression

However one issue with this area of research is that most studies have focused on people convicted of violent crime

Answer 8

• most violence occurs in people who are never convicted & those who are studied only represent a small minority
• this means the sample that findings of many studies are based on are potentially biased & certainly limited
• it’s therefore hard to draw valid conclusions about the role of genetic facts (heritability) in aggression

Question 9

Genetic factors in aggression

Not only is there a problem sampling but there is also a problem of assessing aggression

Answer 9

• In Miles & Careys meta- analysis of 24 studies there was a greater genetic link in studies using a self report than in studies using observation which found a stronger environmental link
• this suggests different research methods yield different results. This therefore means it is difficult to accurately assess the contribution of genetic & environmental factors on aggression

Question 10

Genetic factors in aggression

Thus it is difficult to establish the role of genetic factors on aggression with any certainty

Answer 10

-further challenged by the fact that concordance rates in MZ twins are never 100%, in fact they are less than 50% suggesting that complex behaviour is always a combination if genes and environment as shown in Caspi’s study where anti-social behaviour only occurred if those MAOA-L males had been maltreated as children (explain Caspi in more detail)

Question 11

ethological explanations

Evidence shows just how species specific FAP’s are

Answer 11

• it’s known that most animals respond to pain with aggression but the way it takes differs
• e.g Ulrich showed how the rates given electric shocks will immediately attack each other. This behaviour (FAP) follows a predictable pattern that is unique to rats
• Two hares will however both Stand up on their hind legs & start boxing each other with their front paws
• This behaviour is not known in other species & so lends support to the idea of the universal characteristics of FAP

Question 12

ethological explanations

Lorenz’s idea of ‘instinctive inhibition’ is not supported by evidence

Answer 12

• e.g Jane Goodall observed what she called the ‘four year war’ in a national park in Tasmania. Male chimps promote community by systematically slaughtering all the members of another group in a coordinated fashion
• The violence continued despite the fact that the victims were offering signals of appeasement and defencelessnes suggesting much of behaviour is real & not ritualistic

Question 13

ethological explanations

Ritualised aggression is seen in humans too & has the same benefits for non humans

Answer 13

In non humans ritualistic aggression prevents by preventing conflicts escalating into potentially dangerous physical aggression. Anthropological evidence suggests this advantage is also evident in human cultures e.g Chagnon found the Yanomamo people of South Africa pound their chest & club fight to settle their conflict short of more violence
-suggests that even in fairly violent cultures rituals have the affect of reducing actual aggression preventing death

Question 14

ethological explanations

human FAP of aggression is no longer adaptive

Answer 14

Ebil-Eibesfelt indentified ‘FAP’s’ such as smiling/ eyebrow flash as a sign of greeting

• however because of the environment in which humans exist changes so rapidly Ebil-Eibesfeldt suggests FAP’s e.g aggression are no more adaptive in modern times
• The flexibility of human behaviour & the ability to respond in an ever changing environment has proved more effective than FAP
• this suggests that even though non-human species respond aggressively to specific sign stimuli human behaviour is far more varied & less predictable

Question 15

ethological explanations

Fixed action patterns are not just innate but can be modified by learning

Answer 15

• Lehrman criticised Lorens’z instinctive inhibition explanation of aggressive behaviour. He believed Lorenz had underestimated the role of environmental factors in the development of species ‘FAP’s These environmental factors were largely the result of learning & experience interacting with innate factors
• Nowadats FAP is replaced by the term ‘behaviour pattern’ to replace the fact that these can be modified by experience. Nor is behaviour ‘fixed’
• there are subtle variations between members of the same species in the prediction of aggressive behaviour
• Suggests FAP’s that Lorenz claimed are not as fixed as he thought

Question 16

evolutionary explanations

There is support for the idea that aggression & sexual jealousy are linked

Answer 16

• Wilson found that women who agreed with certain questionnaire items e.g he is jealous & doesn’t want me talking to other men were twice as likely to have experienced serious violence from their partner
• Dobash & Dobash: key cause of violence was extreme jealousy from most battered women
• Suggests sexual jealousy is linked to aggression, however as the results are correlational no firm casual conclusions can be drawn

Question 17

evolutionary explanations

Certain mate-retention strategies used by makes can be an early indicator of violence against a female partner

Answer 17

• knowing this women & their friends can be more aware of the danger signs and potentially take action to avoid any violence ever happening
• educational opportunities: we can teach people better strategies to avoid the more possessive mate retention strategies
• In addition initiatives such as ‘Clare’s law’ now give people the right to have information disclosed about a new partners past

Question 18

evolutionary explanations

The evolutionary explanation can account for gender differences FOR

Answer 18

• men commonly engage in more physical aggressive acts than women
• evolutionary theory explains this: if a female with offspring is aggressive it would put not only her survival at risk but also her children
• more adaptive strategy for females= use verbal aggression as a means of retaining a partner who provides resources

Question 19

evolutionary explanations

The evolutionary explanation can account for gender differences AGAINST (socialisation)

Answer 19

• However sex differences in aggression may be down to socialisation not evolution
• Smetana found that parents are more likely to explain to a girl why a behaviour is wrong and to physically punish a boy. In turn this may increase male violence
• All girls learn they aren’t as strong as boys & therefore might adopt more socially acceptable forms of aggression
• Claimed that only men have evolved aggression but females may simply have learned a different form of aggression

Question 20

evolutionary explanations

There is evidence to suggest that jealousy based aggression has an actual physiological basis

Answer 20

• Takahashi: found mens brains react differently to women to jealousy from brain imagining techniques
• when presented with scenes depicting their partners sexual infidelity men showed greater activation in the amygalda & hypothalamus (brain areas associated with aggression)
• suggests men are biologically wired to respond to sexual infidelity with aggression
• HOWEVER not all men are aggressive- nature nurture- upbringing

Question 21

evolutionary explanations

If aggressive behaviours are evolutionary determined then they should be unaffected by cultural influences

Answer 21

• however the Kung San tribe in Africa has very negative attitudes towards the use of aggression & discourage it from childhood- aggression is rare
• on the other hand the Yanomamo tribe in South America has been described as the ‘fierce people’ Aggression in this culture is acceptable and required in order to gain status
• if aggressive behaviours are evolutionary determined they are unaffected by cultural influences. Evolutionary explanations would predict that aggression is present in all cultures as the motivation for using it would be identical
• the fact that King San & Yanamo have different attitudes towards aggression suggests this behaviour is not universal & its innate nature can be outweighed by cultural & social factors