AGGRESSION

The limbic system - It is though to be closely involved in regulating emotional behaviour. 1st attempt for the link was by Papez and then Maclean, the most important part is the amygdala which is a predictor of aggressive behaviour. Gospic used a labrotory method to assess aggressive behaviour called the ultimatum game, 2 players, the proposer offers to split money in a certain way with the responder, if responder accepts than money is split but if he rejects the offer both recieve nothing, responders had their brain scanned by fMRI which showed when rejecting unfair offers the amygdala had a fast and heightened response. Also benzodiazepine (a drug which reduces arousal of autonomic nervous system) decreased the number of rejections and decreased the activity of the amygdala.

Serotonin - Normal levels of serotonin in the orbitofrontal cortex are linked with reduced firing of neurons and associated with greater degree of behvioural self-control. Low levels of serotonin may disturb this mechanism and reduce self-control and increase impulsive behaviour (Denson). Virkkuenen compared leevls of a serotonin breakdown product in the cerebrospinal fluid of violent impulsive and violent non-impulsive, found lower levels in impulsive offenders and they suffered sleep irregularities.

The male sex hormone testerone has a role in regulating social behaviour by its influence on certain areas of the brain. Giammanco has demonstrated using animal studies that increase in testerone is related to greater aggression, Dolan also found a positive correlation between testerone levels and aggressive behaviours in 60 male offenders.

Role of other brain structures - The amygdala appears to function at the same time with the OFC, which isnt part of the limbic system, the OFC is involved in self-control and inhibition of aggressive behaviour. Coccaro found that with patients with disorders that feature aggression, activity in the OFC is reduced, disrupting its impulsive-control function thus increasing aggression.  The limbic system is a reductionist.

Drugs - Drugs that increase serotonin also reduce leevls of aggressive behaviour. Berman gave ppts a placebo or paroxetine, they then took part in laboratory based game where electric shocks of varying intensity were givenand recieved in reponse to provocation. The paroxentine group gave fewer and less intensive shocks than those in placebo groups.

Role of testerone - Testerone levels change rapidly during the day ecspeaiclly in response to social interactionsrelated to status (e.g. competition). Mehta and Josephs measured chnage sin testerone levels before and after a competition (they all lost). The ppts were given a choice they could challenge for a rematch (aggressive) or do another activity (non-aggressive). Those whose testerone levels rose, 73% rechallenged, those whose testerone dropped only 22% rechallenged. 

Other hormones - Carre and Mehtas dual-hormone hypothesis explains why link of testerone and aggression is mixed. High levels of testorone only leads to aggression if levels of corisol is low, when it is high, testerones influence is blocked.

Issues of cause and effect - Most research is correlational, so it is impossible to establish which is the cause and which is the effect and maybe a third varibale is present. You cant directly manipulate the variable.

Twin studies - Coccaro studied adult male mz and dz twins, for aggressive behaviour defined as direct physical assault a concordance rate of 50 % for MZ and 18% for DZ, For verbal aggression 28% for MZ  and 7% for DZ. Genetics do play a role because MZ twins have a a highe rate than DZ, but  it isnt 100% so environment is also a factor. 

Adoption studies - Waldman carried out a meta-analysis of adoption studies of direct aggresssion and antisocial behaviour, and found that genetic influence accounted for 41% of children were aggressive.

The MAOA gene - Monoamine oxidase is an enzyme and it breaks down neurotransmitters (serotonin) into consistuent chemicals to be recycled, The production of the enzyme is determined by the MAOA gene, and a dysfunction in this gene can affect levels of serotonin in the brain. One variant of the MAOA gen (the warrior gene) leads to low MAOA activity in the brain and is associated with aggressive behaviour. Brunner studied 28 Dutch males who were involved in crimes (****, attempted murder etc) found abnormally low levels of MAOA in the brain. Stuart studied 97 mens who were abusing their partners and were part of a batterer treatment programme. Men with low-activty MAOA gene were found to be most violent.

Gene-environment interactions - Low MAOA gene activity is only related to aggression when combined with early traumatic life events. Frazzetto found an assoication for high levels of aggression and low activity MAOA gene. This was only the case in those who experienced childhood trauma during first 15 years of life. Those who didnt, didnt have highlevels of aggression as adults. Strong evidence of diathesis-stress.

Isolating genetic factors - An indiviudual may possess a gene associated with aggression, but that behaviour is only expressed if the environmental condtions are favourable. e.g. McDermott showed that ppts with low activity MAOA gene in a laboratory based money allocation game, but only when they were provoked. Otherwise they were no more or less aggressive than other ppts.

Multiple genetic factors - Stuart found in domestic violence in men was not only associated with low activity of MAOA gene but also with the serotonin transporter gene (5-HTT), so a combination of the 2 genes that are linked with domestic abuse. Vassos in a meta-analysis could find no evidence for a single gene and aggression.

Measuring aggression - Self-reports, paretn and teacher reports abd direct observations were used. Rhee and Waldmans meta-analysis of 51 twin and adoption studies used self-report. If findings vary depending upon how aggression is measured then it is difficult to draw valid conclusions.

Research support - Mertins studied ppts with low-activity and high-activity of the MAOA gene in a money-distributing game, ppts had to make descions about whether to contribute money for the good of the group. Reserach found males with high-activity were more co-operative and made fewer aggressive moves.

Animal studies - The hypothesis that MAOA gene plays a role in human aggression originates from research from mice. Godar showed that MAOA mice have significantly increased brain serotonin levels and are hyperaggressive, and when serotonin was blocked by a drug; the mice reverted to their non-aggressive behaviour.

Ethological explanantions suggest that the main function of aggression is adaptive. It is beneficial to survival. Another function is to establish dominance hierachies. Pettit studied plays groups of young children and observed how aggression played an important role in the development of some childrens dominance over others.

Ritualistic aggression - Lorenz observed that fights between animals involved little physical damage and mostly consisted of ritualistic signalling. 

All members of the same species (conspecifics) have innate behaviours which occur in certain conditions and these are called Fixed Action Patterns (Niko Tinbergen). These FAPs are produced by a neural mechanism known as an Innate Releasing Mechanism (IRM) and are triggered by a specific stimulus known as a sign stimulus.

 Lea said FAPs have 6 main features: 1) Stereotyped 2) Universal 3) Unaffected by learning 4) Ballistic, once the behaviour is triggered it cannot be altered before it is completed. 5) The behaviour only occurs in a specifc situation 6) A response to an identifiable specific sign stimulus.

Key study: Procedure - Male sticklebacks are highly territoral during the spring mating seasona dn they also develop a red spot on their underbelly. If anothe rmale enters thie territory, a sequence of highly sterotyped aggressive behaviours is initiated. Tinbergen presented sitcklebacks with a series of wooden models of different shapes.

Findings - Regaradless of the shape if the model had a red spot then the sticklebackw ould attack it. But if there was no red spot then there would be no attack. 

Supporting research - The ethological explanation argues aggression is genetically determined and heritable, this is upported by Brunner who showed a low-activity variant of the MAOA gene is associated with aggression, also activity in the limbic system has been shown to trigger aggressive behaviour. So this explanation has validity.

Culture differences - Nisbett found killings are much more common in white males in the southern states than in the nothern states, this was only true for reactive aggression triggered by argumentsso Nisbett concluded that difference in homocide rates was because the response to impulsive aggression was a learned social norm. This was supported by a lab study where when white males were insulted they were more liekly to become aggressive.

Evidence against ritualistic aggression - Goodall observed chipanzees in a 4 year war where male chimps from one communtity set about systematically slaughtering all the members of another group. They done this in a co-oridnated fashion. A victim was held down whule others hit and bit it lastinf ro 20 mins. The violence continued even though the victims were offering signals.

FAPs are not fixed - Hunt said FAP's are greately influenced by environmental factors and learnign experiences. e.g. FAP is typically made up of several aggressive behaviours in a series, the duration of each behaviour varies from one individual to another, and from one encounter to another.

Unjustified generalisation to humans - Lorenz didnt study higher mammals and Tinbergen didnt study the extreme behaviours showed by humans. However they both mad egenralisations about aggressive behaviours in humans. 

Bandura said aggression can be learnt directly though operant conditioning. He said aggression cannot be explained by  such direct forms, so he argued an indirect mechanism - observtional learning.

Children can aquire specific aggressive behaviour through observing models (parents, siblings. media), this doesnt mean they will behave aggressively themsleves because they also observe the consequences of their behaviour and if they see aggressive behaviour being rewarded, it will  be more likley they will  carry out the  behaviour (vicorous reinforcement).

Bandura said there are 4 cognitive conditions needed for observational learning to take place: 1) Attention - observer must pay attention to the models aggressive actions. 2)  Retention - needs to  be able to remember the  aggressive actions, forms mental representation. 3) Reproduction - transform mental into actual physical action. 4) Motivation - needs a  reason to imitate the behaviour, will do so if they will be rewarded.

Self - efficacy - This is the extent to which we eblieve our actions will achieve a desired goal. A childs confidence in their ability to be aggressive grows as they learn aggression can bring rewards.

Supporting research - Poulin and Boivin studied boys 9-12 years old, most aggressive boys formed friendhsips with other aggressive boys, the friendships were mutually reinforcing of aggression. They used their alliance to gain resources with agg behaviour, usually successful. They were exposed to frequent models (eachother) and to positive consequences. Also empirical evidence from Bobo doll, however lacks ecological validity because adults wouldnt do that in real life.

Practical explanations - Because behaviour is learnt from models (parents), so parents  can make sure their behaviour  around their child is calm so children will grow up to be less aggressive. 

Cultural differences -  The Kung San of the Kahari desert, direct reinforcment of childrens aggression is unlikely because social norms do not encourage it and parents tend to use it to discipline children. So models of aggresisve bahaviour are unavailable for children but they still display aggressive behaviour. 

Cannot explain all aggression -  Reactive  - hot blooded, angry  and proactive - cold-blooded and calculated. Children who are proactive have high levels of self-efficacy (they are cofnident their  behaviour will bring benefits).  However reactive  children use aggression to retaliate in the heat of the moment, use aggression to achieve retributuion, this behaviour is less explained by  SLT and better by negative effect theory.

Huesmann and Eron - Media portrayals are powerful infleunces ecsp if child can identify with the model, so vicorous rein forcment may be just has infleuntial as in real life.

SLT ignores the role of nature (testerone levels), prision reserach shows high testerone levels are linked to aggression. Too oversimplified. Agg is a multidimensiona  approach. 

Dollard first came up with this hypothesis. Frustration always leads to aggression and aggression is always the result of frustration. The frustration needs to be relieved in a cathartic way e.g. through a display of aggression, this makes further aggression less likely because we got it off our chest. 

Our aggression isnt always expressed directly against the source of frustration because 1) The cause may be abstarct e.g government, music. 2) The cause may be too powerful and we risk punishment by aggressing against it e.g. teacher. 3) Cause may be unavailable a the time. 

Also people will display aggression if if they believe it will remove the barrier that is causing frustration. If they believe their behaviour is justified then they will be aggressive g.g. Doob and Sears bus went by without stopping, people will feel angry but if the bus had a sign saying it was out of service, they would feel less angry because it is a justified reason.

Green got male uni students to do a puzzle and for some ppts the puzzle was impossible to solve, for others they ran out of time coz confederate got involved. For third group the confederate insulted the ppts as they failed to solve the puzzle. Then the ppts had to shock the confederate when they made a mistake on another task. 

The insulted ppts gave the strongest shocks, then the interfeered group, then the impossible task. All 3 gave more than the control group.

Critcism - Bandura criticised this hypothesis coz he said it is just one possible response to frustration, he said frustration only created arousal and it was social learning which determines how that arousal then influences the perosn behaviour, person would only respond with aggression if they had learned that behaviour is effective. Children were frustrated before seeing the bobo doll but not all children hit the bobo doll. So frustration leads to aggression with learning aswell. So this hypothesis is a reductinist and Bandura offers a holistic approach.

Cathartic - Bushman found ppts who venetd their anger by repeatedly hitting a punchbag actually became more angry than less. Doing nothing was more effective at reducing anger. This theory lacks validity because it isnt able to account for all forms of aggression.

Justfied and unjustified - Dill and Anderson, an experimenter showed ppts oragami, he made it difficult to follow y going to quick, in unjustified he said he had to meet his girlfriend and in justified he said his boss told him to finish quickly. The unjustified produced the most aggression.

Gender bias - Both genders feel the same frustration but men tend to be moe aggressive. Bandura suggests the the expectations of gender roles which encourage men to act on their frustration.

Le Bon came up with the concept of de-individuation to explain behaviour of individuals in crowds. When we become part of a crowd we have the freedom to behave in ways we wouldnt otherwise contemplate, we lose our perosnal identity and take on the identitiy of the social group. We have gretae disreagrd for social-norms adn we experience less perosnal guilt.

Zimbardo said when we are in a de-individuated state we lose self-awareness, we stop monitoring our own behaviour and ignore social norms and live for the moment without making longer-term plans. Conditons such as darkness, drugs, alcohol, uniforms, and masks promote aggression. Mahendan said anoniminity is a major factor because we have less fear of retribution because we are unidentifiable, also less oppurtunities for others to judge us negatively.

The 2 types of self awareness are 1) Private self-awareness - We pay less attention to our own beliefs and feelings because our attention is focused on the vents around us. We are less self critical and less evaluative. 2) Public self awareness - How much we care about what others think of our behvaiour which is reduced in crowds. We realise we are anonymous and we are less likely to be judged by others. We become less accountable.

Dodd illustrated de-individuation by asking 229 students in 13 classes "if you coud do anything without getting caught what would it be?" . The students knew their responses would be anonymous.

Findings - 36% of responses involved some form of anti social behaviour, 26% were criminal acts e.g. rob a bank, a few said murder, ****. Only 9% said parasocial bheaviours such as helping people. This study demonstrtes link between anonymity and aggressive behaviour.

Research support - Douglas and McGarty looked at behaviour in online chatrooms, found strong correltion between anonymity and sending or posting threatening or hostile messages. This has great relevance today because of social media.

Lack of support - Gergen selected 8 ppts who were all strangers, they were put into a dark room and told to do whatever they wanted to, with no rules. It was impossible for ppts toidentify eachother and they were told they would never encounter each other again, this made them kiss and touch eachother inimately. This study was repeated but this time ppts were told they would see eachother after and then touching declined. De-individuation didnt give a rise to aggression.

Pro social behaviour - Johnson and Downing made females gives fake electric shocks to confederates. In one condition they wered dressed in KKK outfit, in 2nd dressed as nurss and in third in their normal clothes. The KKK ppts gave more shocks and the nurses gave fewer at lower levels, the nurses were also more compassionate towards their victim in line with the prosocial role associated with a nurses uniform. Normative cues in the situatuon determine if you will display aggression or not.

Aggression in handball Deindividuation  was created by giving one team orange shirts, whilst other team wore own clothes.In boy teams, uniformed teams were more aggressive than non-uniform.In girl teams, no differences found.Researchers concluded that uniform > loss of individuality > deindividuation. This shows that biological factors come into play because girls were less aggressive.

Dispostionsl explanations (The importation model) - Irwin and Cressey said people bring aggression into prisons because agression might be the reason why the person ends up in prison. They bring their beliefs, values, attitudes, race and class. Individuals may live in a subculturw ehre being aggressive is valued, respected and rinforced and so when they go into prision where they are faced with unfamilar situations which can be scray they use aggression to establish power and status. Delisi studied 813 juvinile dilequients who came into prision with several dispostional features like childhood trauma, anger, substance abuse etc. He found that these inmate were more likely to engage in more acts of physical violence.

Situations explanation (The deprivation model) - Clemmer said harsh prison environments are stressful for inmates, who cope by being aggressive. Conditions include being depried of freedom, independence, safety, intimcay. Deprivation of material goods increases competition for inmates to aquire them and they us aggression. Aggression is also influenced by the nature of the prison regime, if it is unpreidtable and sues lock ups to control bhevaiour this creates frustration and results in violence which is an adaptive solution to the problem. Steiner investiagted 512 prisons in US. Violence was more common in prisons with more female staff, African-American inmates, Hispanic inmates - all prison level factors.

Research support - Camp and Gaes sudied 516 male inmates with similar criminal histories. Half were placed in low security prisons and other half in high security. 33% in low and 36% in high were involved in aggressive misconduct within 2 years, this result is not statistically significant so researchers concluded that festures of the prison environment were less important than charcteristics. This is strong evidenc ebecause it is a field experiments with random allocation and so more valid conclusions can be drawn.

Alternative explanation - Dililio sad importation model ignres the roles of prson officals and factors related to te running of prisons. He said poorly managed prisons are mor eliekly to experince more serious forms of violence, poor management shows weak leadersip, unofficial rule and included staff who remian distant from inmates. These factors are inluential in determining aggression. 

Supporting evidence - Cunningham analysed 35 inmate homocides in Texas prisons and found tht motivations for homocides were some of the deprivations that Clemmer found. Important arguments were drugs, homosexual relations and possessions. Support validity. 

Contradictroy research - Hensley studied 256 male and female inmates which allows conjugal visits (visits from partners to have sex). There was no link between involvement in these visits and reduced aggression. So situational factors no not affect prison violence.

Interactionist model - Jiang said that the importtation model is better for violence between inmates and deprivation is better for aggression against prison staff. Dobbs and Waid said inmates entering prison for the first time will suuffer deprivation but that alone doesnt lead to violence until it combines with the individuals charceteristics.

Experimental studies - Lab study by Anderson. Students played either violent game or non violent game for 10 minutes. Then carried out the TCRTT a standard meaure of aggression in which studnets deliver blasts of white noise at chosen volumes to punisha non-existent oponent. Those who played the violent game slected higher noise levels. 5.97 deibels.

Correlational studies - DeLisi studied 227 juvinielle offender all with histories of aggressive behaviours. Using structured interviews they gathered data on several measures of agg and violent computer game oaying. Found those correlation betwen aggressive behaviour and how often they played computer games and how much they enjoyed them. 

Longitudinal studies - Robertson wanted to see link betwen exxcessive tv viewing in childhood and aggresive behviour in adulthood. Studied 1037 ppl born in Wew Zeland and measured tv veiwing hours at regular intervals until 26 years. Found time spent watching tv wa a reliable predictor of aggresisve behaviour. Those who watched most tv were more likely to be diagnosed with antisocial perosnality disorder and have aggressive traits.

Meta-anayses - Anderson got 136 studies which incldued all 3 types of methologies and found violent computer games was associated with aggressive beviour, thoughts. True for male and female in collectivist and indvidualist.

Experimental studies - Allow us to establish a casual link between variables. However in labs, situations are artifical and unrealistic such as the TCRTT but it would be unethical to allow realistic forms of aggression. Also lab situations do not involve any fears of retaliation unlike in the real world. Experimenter gives the ppt permission to be aggressive. Also it is difcciult to be certain that the violent and non-violent game are equiavelnt aprt from the violence.

Correlational studies - Allows us to investigate realistic forms of agg. However cannot draw a cause and effect conclusion. No variables are manipulated or controlled and their is no random allocation of ppts. e.g. aggressive media coudl make you more aggressive or people who are already aggressive select aggressive media. 

Longitudinal studies - Studying change overtime leaves these studies vulnerbale to the effects of cofounding variables, many other sources interact with media influence such as friends, families etc. It becomes difficult to seperate them and assess their contributions. 

Publication bias - Publishing findings that are statistically significant. Problem for meta analyses beause they only include published studies

Desensitisation - When we see violence we experience physiological arousal such as increased heart rate, sweat. But when we see repeatded aggression we become habituated to its effcets, so it lowers our phsiological arousal and reduces anxiety. Repeated exposure to violence promotes belief that suing aggression is acceptable and negative attitudes towrads agg weaken. Less empathy for victims. Lab study by Earls where they showed ppts film called Straw Dogs whic had a **** scene, ppts then wtached re-anactment of **** trial and then male viewers showed greater acceptance of **** myths and sexual aggression and showed less symptahy for **** victim. No such effect on females of film type.

Disinhibtion - There are powerful social and psyhcological constraints against using aggression and these are learnt directly and indirectly by SLT. The usual constraints are loosened after exposure to violent media. In media aggressive behaviour is made to seem normative and socially sanctioned. It minimises the effects of violence on its victims and says it justified. This creates new social norms in the viewer.

Cognitive priming - Repeatedly viewing aggressive media provied us with a script about how violent situations may play out. Huesmann said the script is stored in memory so we beocme ready to be aggressive, the process is automatic and the script is triggered when we encounter cues in a aggressive situation. Fischer looked at song lyrics, when male ppts listentened to songs with degrogatory lyrics about women compared with neutral lyrics.

Research support for desensitisation - Kraheshowed ppts violent and non-violent film clips and measured physiological arousal using skin conductance. particpants who were habitual viewers of violence showed lower levels of arousal. They reported higher levels of pleasant arousal. Lower levels of arousal was correlated with unprovoked aggression in a noise blast task. 

Research support for disinhibition - Berkowitz found that ppts who saw a film depicitng aggression as vengance gave more electric shocks of longer duration to a confederate. Media violence may disinhibit aggressive behaviour if it is justified. Venegance is a powerful justifcation for violence and justified violence is seen as socially acceptable. This adds validity because it demonstrates link between removalof social constraints and subsequent aggressive behaviour. 

Practical application of cognitive priming - 

Alternative explanation for desensitisation - Krahe failed to find a link between media viewing, lower arousal and provoked aggression. Suggests that desensitisation may not explain the impact of ciolent meida exposure on all forms of behaviour. Another explanation might be catharsis, psyhcodynamic theory that viewing violent media acts as a safety valve mechanism, allowing people to release aggressive impulses without the need to behave violent.

Explaining cartoon violence - Aggression carried out by media models is partly infleuntial because it suggests to the observer that it is socially normative ecspecially when it goes unpunished. 

Sexual jealousy can be given an evolutionary explanation. This is because men can never totally be sure if they have fathered a child. Any inestment in the offspring that doesnt share the males denes is a waste of his resources and then he has less resources for his own children.  Men who could avoid cuckoldry (husband of someone whose cheating) were more reproductively successful. Sexual jealousy is more strongly experienced in males, this drives aggressive stratergies men employ to retain their partners. 

Mate retention stratergies - Wilson identified different stragteries: 1) Direct guarding - involves watching partners behaviour, checking who they've been seeing. 2) Negative inducements - such as threats of dire consequenes for infedility "i'll kill myself if you leave". Such behaviours are linked to violence. Wilson found women who reported mate retention stratergies in thier partners were twice as likely to suffer physical violence at the hands of their partners.

Intimate partner violence (Shackelford) - 107 married couples completed questionairres, they'd all been married less than a year. Men done mate retention inventory which assessed mate retention behaviours. The women done the spouse influence report which measured the extent of their partners violence. Strong positive correlation between mens reports of mate retention and women report of their partners violence. 

Bullying - Bullying occurs because of a power imbalance. Our evolutionary ancestors may have used bullying as an adaptive stratergy. Volk said charcetristics associated with bullying are attractive to the opposite sex, in males it suggests dominance. Women use bullying to secure their partners fidelity so they can continue and provide resources. 

Accounts for gender differences - Evolutonary can explain why men are more aggressive. Campbell argues that females with her own offspring are motivated to be less aggressive coz it will put her and her offspring at  risk. So females have adapted to use verbal aggression to retain partners who provide resources and to avoid life-threatening situations. This explains why women are more likely to use non-aggressive methods to resolve disputes.

Real-life - Evolutinary approach acknolwegdes that bullies bullybecause they gain advantages so it makes no sense from them to give up their power without some sort of compensation. Help us make anti bullying interventions. Volk says anti-bullying interventions njedd to increase the costs of bullying and the rewards of rposocial alternatives. One method could be to encoruage them to compete aggressively but fairly in sporting activities. This would allow to display attractive qualities.

Cultural differences - Kung San people, aggression is discouraged from childhood and is rare. Those who do use it find that their status and reputation within the community is diminished. 

Methodological issues - Difficult to test hypotheses about the evolution of behaviours. So most research is correlational and this does not allow us to draw a cause and efefct conclusion.

Research support - Many reserach suggets that mate retention is associated with sexual jealousy and aggression. Stratergie such as firect guarding and geative inducement are overwhlemingly used agaisnt females. This indicates a clear link between infedility and aggression. and support the adaptive value of aggression.