Aggression

Aggression

1. Biological explanations for aggression

   • Neural mechanisms
     • The limbic system: Network of structures in the brain (including the hypothalamus and amygdala) thought to be closely involved in regulating emotional behaviour including aggression.
       • Amygdala- located in the limbic system in the temporal lobe. Its function is for memory and emotion- especially fear. It is responsible for learning from the negative consequences of our actions and negative facial expressions. Believed to be dysfunctional in aggressive people
         • The relationship between the amygdala and the rest of the limbic system and its link to aggression is a complex one. This is because stimulating different areas have been found to both inhibit and increase aggressive behaviours.
         • Mark and Ervin - case study on a female patient who, during electrical stimualtion of the amygdala, at first exhibited facial grimacing, then became very angry, and ultimately flung herself against the wall. This suggested that stimulation of the amygdala can lead to aggressive behaviours.
           • The amygdala functions in tandem with the orbitofrontal cortex (OFC) to maintain self-control. Coccaro et al showed OFC activity is reduced in patients with disorders that feature aggression. This shows the regulation of aggression cannot be explained by the limbic system alone-complex.
     • Serotonin- a neurotransmitter with widespread inhibitory effects throughout the brain. It has a key role in aggressive behaviour.
       • A decreased amount of this biochemical in the orbitofrontal cortex reduces self-control which leads to an increase in impulsive behaviour.
       • Virkkunen et al found that levels of serotonin breakdown product (5-HIAA) in the cerebrospinal fluid were significantly lower in violent impulsive offenders compared to violent non-impulsive offenders. They also suffered from more sleep irregularities-serotonin regulates sleep patterns.
         • Research showing a correlation between serotonin and aggression risks oversimplifying the true mechanisms involved as other factors which influence or even cause aggression are overlooked. Neural and hormonal regulation of aggression is almost certainly more complex than we currently think.
   • Hormonal mechanisms
     • Testosterone- A hormone from the androgen group that is processed mainly in the male testes (and smaller amounts in the female ovaries). Associated with aggression.
       • Testosterone moderates levels of various neurotransmitters that mediate the effects on aggression. There has been a wealth of research into this area in both human and non-human animals, finding testosterone as a universal cause.
       • Beeman- castrated male mice and found that their aggression was reduced. He further demonstrated the importance of testosterone by later injecting the mice with testosterone which re-established their aggressive behaviour.
         • Evidence in humans is mixed, some shows hormones other than testosterone are also significantly involved. The dual-hormone hypothesis claims high testosterone leads only to aggression when cortisol is low- high cortisol blocks its influence on aggressive behaviour.
   • Genetic factors
     • The genetic explanation explains behaviour as a result of internal bodily processes. It suggests that certain behaviours are inherited. Genes do not directly cause aggression, but influence elements of our biology to contribute to this.
     • MAOA- A gene that is found in the X chromosome. It is responsible for producing an enzyme which cleans up excess neurotransmitters, especially serotonin, into their constituent chemicals to be recycled or excreted. If this gene is impaired, the enzyme doesn't work as it should and so serotonin levels change, leading to impulsive behaviours.
       • Brunner et al- 28 males of a dutch family who had a history of extreme violence, such as rape, attempted murder and assault. Brunner discovered that the men were suffering from a defective MAOA gene, by detecting serotonin build up in their urine.
       • Cases et al- studied mice genetically engineered to lack MAOA. The mice has severe behavioural alterations. When adult, they showed enhanced aggression and were aggressive during mating.
         • Hundreds or thousands of genes interact in complex ways, casting doubt over any search for single candiate genes
     • Twin studies- monozygotic twins are genetically identical, therefore any similarities in aggressiveness might be attributable to shared genes, whilst differences in aggression between them could be due to environmental factors.
       • Coccaro studied male MZ and DZ twins. For direct physical aggression, researchers found concordance rates of 50% for MZ and 19% for DZ. For verbal aggression concordance was Mz 28% and DZ 7%.
       • It's difficult to separate genetic and environmental factors. Someone with an aggression-associated gene may only behave aggressively if the environmental conditions are suitable.
     • Adoption studies- similarities in aggressive behaviour between an adopted child and their biological parents suggest that genetic influences are operating.
       • Gabrielli & Hutchings- studied criminal records of Danish children adopted outside of their biological family. They found that the criminal records of adopted children were more similar to those of their biological parents than their adopted parents, suggesting a genetic component in aggression.
         • Findings vary depending on how aggression is measured so it is difficult to 'pin down' the real causes of this behaviour and draw valid conclusions about the role of genetic factors.

2. Ethological and Evolutionary explanations for aggression

   • Ethological
     • Adaptive functions of aggression
       • Aggression is said to be adaptive. Aggression is beneficial to survival because a 'defeated' animal is rarely killed, but rather is forced to establish territory elsewhere. This means that members of a species spread out over a wider area and have to discover resources from another place.
         • It is also used to establish dominance in hierarchies. Male chimpanzees use aggression to climb their troop's social hierarchy. This would be adaptive because dominance over others brings benefits such as the power to get your own way and access to resources.
     • Ritualistic aggression
       • One of Lorenz's intriguing early observations of fights between animals was how little actual physical damage was done. Most aggressive encounters consisted mainly of a period of ritualistic signalling and rarely reached the point of becoming physical.
       • Lorenz pointed out that intra-species aggressive confrontations end with ritual appeasement displays. These indicate acceptance of defeat and inhibit aggressive behaviour in the victor, preventing damage to the loser. This is adaptive because if every aggressive encounter ended with the death of one of the combatants, that could threaten the existence of the species.
         • Research observed male chimps from one community systematically slaughter the members of another group in a coordinated fashion. This happened despite the victims offering signals of appeasement and defencelessness. These did not inhibit the aggression of the attacking chimps as predicted by ethological exp.
           • Lorenz did not study higher mammals such as primates and Tinbergen chose not to study the extreme destructive violence seen in human aggression. They both made generalisations from animal aggression to humans. Lorenz extrapolated from the behaviour of individual animals to the behaviour of entire countries.
     • Innate releasing mechanism: A built-in physiological process or structure, for instance a network of neurones in the brain. An environmental stimulus (such as certain facial expressions) triggers the IRM which then 'releases' a specific sequence of behaviours. This behavioural sequence is called a fixed action pattern.
       • Lea described FAPs as being: Stereotyped/unchanging, universal, unaffected by learning, Ballistic (once triggered it follows an inevitable course and has to be completed), single-purpose and has a specific cue/releaser.
     • Tinbergen- found that male sticklebacks were only aggressive in response to other male sticklebacks invading their territory. Other male sticklebacks are noticeable by a red dot on their underbelly. Regardless of shape, if the model had a red spot the stickleback would aggressively display and even attack. If there was no red spot, there was no aggression. These FAPs were unchanging from one encounter to another and always ran its course to completion without any further stimulus.
     • Nisbett found there was a north-south divide in the USA for homicide rates. Killings are much more common amongst white males in the southern states than in the northern states. Because this was only true for reactive aggression triggered by arguments, Nisbett concluded that the difference in homicide rates was caused by a 'culture of honour' (being a social norm). Culture overrides innate influences.
   • Evolutionary
     • The evolutionary approach suggests that life is a competition and the ultimate goal is genetic survival. Evolutionists would suggest it is this that drives most behaviour, including aggression.
       • Male jealousy is suggested to be adaptive to the problems that they face with regards to sexual selection. Some men are faced with paternity uncertainty, meaning that they can never be certain that they are the father of their child. Therefore they could be at the risk of cuckoldry (raising offspring that isn't their own). In sexual selection terms this is a problem as the male is not able to pass on their own genes. Women do not have the same problem as they are 100% certain their child is theirs. It is suggested that males have evolved feelings of jealousy to trigger behaviours that will prevent a partner's potential infidelity. One main way to do this is with aggressive behaviour such as sexual coercion.
     • Mate retention strategies: Wilson and Daly identified two strategies which involve aggression an even physical violence. : Direct guarding- stalking, checking whereabouts. Emotional manipulation: threats and blackmail.
       • Wilson: Women who reported that their partners used mate retention strategies were twice as likely to have suffered physical violence in their relationship.
     • Bullying occurs because of a power imbalance: a more powerful individual uses aggression deliberately and repeatedly against a weaker person. Our evolutionary ancestors may have used bullying as an adaptive strategy to increase their chances of survival by promoting their own health and creating opportunities for reproduction.
     • Shackleford- surveyed 107 married couples about the use of mate retention strategies in committed heterosexual relationships and also the degree of violence they showed to their partners. A strong positive correlation was found between men's reports of their mate retention behaviours and the women's reports of physical violence.
     • It is argued that aggression in females risks survival of their offspring so a more adaptive strategy is to use verbal aggression to retain a partner for resources. By being able to explain gender differences , it increases the validity of this approach.
     • An evolutionary understanding of bullying as adaptive behaviour can help us to devise effective anti-bullying interventions, to increase the costs of bullying and the rewards of pro-social alternatives.

3. Social psychological explanations of aggression

   • Frustration-aggression hypothesis
     • The hypothesis suggests that frustration always leads to aggression, and aggression is always the result of frustration.
       • Frustration is caused by being unable to achieve goals which then leads to an aggression drive that increases and has to be released through some sort of aggressive behaviour. This leads to the aggressive drive reducing as the person has found a way to release these negative feelings (catharsis) . Aggression is not always expressed directly against the source of frustration due to the source of frustration being abstract, powerful or available.
         • Geen studied male uni students who were given the task of completing a jigsaw puzzle. Their level of frustration was manipulated by either; having an impossible puzzle, being interfered, or being insulted. When given the opportunity to shock the confederates, those who insulted participants received the strongest shocks, followed by those who interrupted them and then those who gave the impossible puzzle. All gave greater shocks than the control group.
     • Environmental cues: According to Berkowitz, frustration merely creates a readiness for aggression, the presence of aggressive cues in the environment make acting upon this much more likely. Therefore cues are an additional element of the hypothesis.
       • Berkowitz had student participants be given electric shocks in a lab environment in order to make them angry and frustrated. When given the opportunity to shock the person who had shocked them, participants were more likely to give shocks if there were weapons present. This is known as the weapons effect and supports the idea of environmental cues.
         • The arguments that 'the trigger can pull the finger' has influenced the gun control debate in the US. Some states allow 'open carry' where the gun does not have to be concealed. But presence of a weapon acts as a cue to aggression making it more likely. This research may reduce gun-related violence by removing aggressive cues.
     • Bushman found that participants who vented their anger by repeatedly hitting a punchbag actually became more aggressive rather than less. In fact, doing nothing was more effective than venting anger. Bushman argues that using venting to reduce anger is like using petrol to fight a fire.
   • Social learning theory
     • This theory suggests that aggression is learned through a mixture of indirect and direct reinforcement.
       • Indirect reinforcement involves people learning through observing and imitating aggressive role models. The child is then more likely to imitate behaviour in future if they see a role model being rewarded for showing that behaviour (vicarious reinforcement), whilst less likely to carry out the behaviour if the role model is punished for it (vicarious punishment).
         • In the !Kung San tribe, social norms do not encourage aggression, so aggressive models aren't available for children to observe and reinforcement is rare. But people of the !Kung San still behave aggressively.
       • Direct reinforcement is where a person is more likely to repeat the behaviour in future if they are rewarded when they carry it out, whilst less likely to carry it out if it leads to a negative outcome (punishment).
     • Bandura described the four conditions required for observational learning to take place:
       • Attention: observer must pay attention to the model's aggressive actions.
         • Retention: the observer needs to be able to remember the aggressive actions to form a symbolic mental representation.
           • Reproduction: Individual must be able to transform the mental representation of the aggression into an actual physical action.
             • Motivation: individual needs a reason to imitate the behaviour.
     • Self-efficacy is the extent to which we believe our actions will achieve a desired goal. A child's confidence in their ability to be aggressive grows as they learn that aggression can bring rewards.
     • SLT can explain inconsistencies in aggressive behaviour- individuals may behave aggressively in different situations such as work, but not others, this is because aggression provides rewards in certain situations. However it doesn't explain individuals who constantly use aggression in retaliation, even when it is not beneficial to them. Such as extreme violence.
     • Bandura's 'bobo' doll: young children observed an adult model assaulting an inflatable doll. The children were then allowed to play with some toys, including the bobo doll. Those who saw an adult attacking the doll, did so as well, particularly if the adult model was the same gender. Those who didn't watch the adult acting aggressively, did not attack the bobo doll.
     • highlights practical benefits of non-aggressive models. Providing children with models of non-aggressive behaviour is a practical benefit of understanding aggression as a social learning process. This is especially true if a media character is rewarded for being aggressive.
   • Deindividuation
     • An individual becomes deindividuated and therefore aggressive, when they lose their individuality and personal identity.
     • Zimbardo's critical factors: -Anonymity. -Reduced responsibility. -High arousal. -Under the influence. -Sensory overload.
     • Crowd behaviour: Le Bon claimed that in a crowd, a 'collective mod mindset' is created and the group act as one. People are not normally aggressive because they can be identified and social norms prevent it. However, in this mob mind-set the individual becomes aggressive because their self-awareness and fear of being judged is reduced.
       • Gergen- groups of eight participants who were all strangers to each other were placed in a dark room for one hour. When they were told they could not identify each other or encounter each other again, participants began kissing and touching each other immediately. When they were told they would meet again after the hour, the amount of contact declined dramatically.
         • Dodd- 229 students were asked 'if you could do anything humanly possible knowing you wouldn't get caught or held responsible, what would you do?'. 36% of responses involved antisocial behaviour; 26% were actual criminal acts. Only 9% of responses were prosocial behaviours.
     • Self-awareness: when an individual's self-awareness is blocked by environmental events, they feel different and less concerned about consequences of behaviour. Individuals act more impulsively, focusing on their own feelings.
       • Public self-awareness is how much me care about what other people think about us. This is reduced in crowds where we realise we are anonymous and our behaviour is less likely to be judged by others.
       • Private self-awareness is how we pay attention to our own feelings and behaviour. This is reduced in crowds where our attention becomes focused on our surroundings and we become less self-critical.
       • Real life applications- helps us understand aggressive behaviour in online chat rooms and gaming services like Xbox Live. These services promote deindividualtion- reducing personal identity and an arousing environment.

4. Institutional aggression

   • Dispositional explanations
     • The importation model claims that inmates who enter the prison with particular characteristics (beliefs, norms, attitudes, traits) are more likely to engage in aggression than other inmates. Therefore aggression is not the product of the prison itself but rather the personality of individuals within the institution. The aggressive behaviour seen in the prison environment is the same behaviour these individuals show in all environments.
     • Pre-existing factors of individuals affect the levels of aggression shown in prisons. Inmates import these to negotiate their way through the unfamiliar prison environment, in which existing inmates use aggression to establish power etc.
     • DeLisi studied 813 juvenile delinquents in prisons in California. These were inmates who brought into confinement several negative features such as experiences of childhood trauma, anger and irritability, and a history of substance abuse and violent behaviour. These inmates were more likely to engage in suicidal and violent acts compared to a control group of inmates with fewer negative characteristics.
       • Dilulio claims that the importation model is inadequate because it ignores the roles of prison officials and management. He stated that prisons with weak and indecisive leadership, informal and unofficial rules, distant staff and poor education are more influential in determining aggression than inmate characteristics.
   • Situational explanations
     • The deprivation model suggests that institutional aggression is caused by the prisons rather than the inmates, where the living conditions of the prisons are a recipe for violence. Deprivation of liberty (freedom), autonomy (independence), goods and services (belongings and hobbies), sexual relationships and security (safety and privacy) are explained as causing stress and lack of control. This in turn causes aggressive behaviour.
       • A lack of prison control and fairness, increases inmate frustration. This is a recipe for aggression, which becomes an adaptive solution to the problem of deprivation.
     • Steiner- investigated inmate aggression in 500 prisons in the US. inmate-on-inmate violence was more common in prisons with more female staff, African-American inmates and inmates in protective custody for their own safety. These prison-level factors reliably predicted aggressive behaviour.
     • Hensley et al studied two prisons in Mississippi where conjugal visits (from partners to have sex) were allowed. there was no link between involvement in these visits and reduced aggressive behaviour. This casts doubt over the deprivation model.
   • The interactionist model suggests that the importation model is more useful in explaining violence between inmates, and the deprivation model is more useful in understanding innate aggression against prison staff. Deprivation does not necessarily lead to violence unless or until it combines with the individual characteristics imported by inmates. This is a more valid explanation because it offers a fuller account, explaining a greater variety of aggressive behaviours.

5. Media influences on aggression

   • Computer games
     • Experimental studies
       • Anderson et al- students played either a violent computer game or nonviolent game for ten minutes. They all then carried out a lab measurement of aggression task where they delivered blasts of white noise at chosen volumes to punish a (non-existent) opponent. Those who played the violent game gave significantly more noise than nonviolent players
         • Lab studies are good at establishing cause and effect due to the controlled conditions. - However, the situations are often described as being artificial and unrealistic. It would be unethical to allow realistic forms of aggression in an experiment and so researchers have no choice but to be creative in devising ways of measuring aggression.
         • They do not involve any fear of retaliation, unlike in the real world, participants have permission to be 'safely' aggressive.
     • Correlational studies
       • DeLisi et al. 227 juvenile offenders with aggressive histories were interviewed (structured) about aggression and violent computer-game playing. Aggressive behaviour was positively correlated with how often they played violent games and how much they enjoyed them. Claimed the link is so well-established that computer game violence should be considered a significant risk factor.
         • No variables are manipulated or controlled and there is no random allocation of participants to each condition to establish cause and effect. A correlation between violent games and aggression could be explained by the games making people aggressive, or aggressive people choosing violent games.
     • Longitudinal studies
       • Robertson et al- studied 100 people from new zealand, measuring their TV hours at regular intervals up to the age of 26 years. Time spent watching TV was a reliable predictor of aggression in adulthood and APD diagnosis.
         • Longitudinal studies view people as active consumers rather than as passive recipients, giving a more realistic view of how people interact with media. However, studying people over time means you cannot separate the effects of confounding variables e.g role models, leaving it difficult to conclude what has affected aggression.
   • Media
     • Desensitisation
       • Normally when we witness aggression we experience arousal associated with the sympathetic nervous system (increased heart rate, sweat, etc.). But when children repeatedly view aggression on TV etc. they become habituated and the physiological effects are reduced.
       • Repeated exposure to violent media promotes the belief that aggression is socially acceptable and therefore weakens the negative attitudes towards it.
       • Krahe et al- showed participants violent and non-violent film clips while measuring physiological arousal using skin conductance. Frequent viewers of violent media showed lower anxious arousal when watching the clips and higher pleasant arousal.
         • Desensitisation may not explain the impact of violent media on all forms of aggression. Catharsis may be a more valid explanation- viewing violent media acts as a safety value, allowing people to release aggressive impulses without behaving violently.
     • Disinhibition
       • Most people believe violence and aggression are antisocial- and so there are powerful social and psychological restraints against using it. These are learned by SLT. Violent media gives aggressive behaviour social approval , especially where effects on victims are minimise or 'justified'. This means the usual restraints on individuals are loosened (disinhibited).
         • Berkowitz- found participants who saw a film depicting aggression as vengeance gave more, longer (fake) electric shocks to a confederate. This suggests that media violence may disinhibit aggressive behaviour when it is presented as justified.
     • Cognitive priming
       • Repeated experience of aggressive media can provide us with a 'script' about how violent situations 'play out'. This is an automatic process because it is stored in our memory and can direct our behaviour without us being aware of it. The script is triggered when we encounter cues in a situation that we perceive is aggressive.
         • Understanding cognitive priming influences on aggression can potentially save lives- whether situations break into violence depends on how individuals interpret cues which depends on memory scripts. This raises the possibility that effective interventions could reduce aggressive behaviour by challenging hostile cognitive scripts.
       • Greitemeyer- had male participants listen to songs with aggressively derogatory lyrics about women. Compared with when they listened to neutral lyrics, participants later recalled more negative qualities about women and behaved more aggressively towards a female confederate.

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