Aggression Flashcards
Outline the role of the limbic system in aggression
-plays key role in how an organism responds to environmental threats/challenges
-hence is key factor in whether we respond aggressively or not to an external stimulus
-Papez-Maclean limbic theory involves structures like the amygdala, hypothalamus and hippocampus
-these are implicated in reactive aggression (response to perceived threat)
-proactive aggression is a response in anticipation of a reward
-limbic system connects to the cingulate gyrus (responsible for focusing attention on emotionally significant events)
-limbic system has connections to the prefrontal cortex (involved in forward planning and anticipation of reward)
Hypothalamus:
-responsible for regulation of autonomic nervous system
-this in turn regulates responses to emotional circumstances
-hence damage to this area can result in an inappropriate aggressive response to a perceived threat
Amygdala:
-responsible for attaching emotional significance to sensory information
Pre-frontal Cortex:
-where feelings are monitored and interpreted, which then triggers a physical response
-crucial for regulating social behaviour and aggressive responses
-damage would reduce the inhibition of the amygdala resulting in higher levels of aggression
Outline the role of serotonin in aggression
-normally, serotonin works on the frontal areas of the brain to inhibit the firing of the amygdala
-hence serotonin has a calming influence
-low levels of serotonin mean that people can’t control their impulsive and aggressive behaviour
-it also regulates the pre-frontal cortex, so lower levels of serotonin affect our response to external stimuli
-hence the person becomes aggressive easily and can’t control their in a ‘normal’ way.
-can’t anticipate risk, hence impulsively engage in aggressive behaviour.
Outline the role of the testosterone in aggression
-observations of non-human and human species have demonstrated that aggression is more evident in males than in females
-animal studies have led to the explanation that male hormones are implicated in aggression
-main hormone which decides whether an embryo develops into a male or female is testosterone. -testosterone peaks in young adolescent males before gradually declining with age
-also promotes muscle strength and is responsible for the sex drive, but is also implicated in aggression.
Evaluate neural and hormonal mechanisms in aggression
Strength - research support by Kluver and Bucy (1939) who removed parts of the limbic system including the amygdala, hippocampus and surrounding cortical areas from rhesus monkeys
-found that monkeys displayed an absence of emotional, motor and vocal reactions normally associated with stimuli or situations eliciting fear and anger
-lesioned monkeys also lost the social understanding of group hierarchies and would try to fight the more dominant and larger members of the group
-demonstrates importance of the limbic system in regulating aggressive responses
-however, one of the main criticisms of research using animals to provide evidence for aggression in humans is the differences between animal and human physiology
-furthermore, question arises of whether we can extrapolate research findings from animals to human aggressive behaviour
-despite humans and monkeys both possessing similar neural structures, we cannot be sure that the processes involved in mediating aggression in humans are the same as those shown in animals such as the Rhesus monkey
Strength - recent technological advances have allowed neuroimaging techniques such as MRI scans to investigate relationship between neural structures such as the amygdala and aggressive behaviour
-Wong et al. (1997) undertook MRI scans of 19 violent male criminals in Broadmoor hospital
-compared the size of the amygdala with 20 ‘normal’ control subjects
-found that volume of the amygdala was significantly smaller in the 19 violent criminals
-hence supports role of the amygdala and limbic system in aggression
-however, lacks population validity
-relatively small sample, hence raises issue of whether these findings can be generalised to the wider population
-research can be accused of beta bias, as their research was confined to males
-hence, caution must be taken in using this research to explain aggression in females
Strength - research support for role of serotonin in aggression
-Ferrari et al. (2003) allowed adult male rats to fight with another rat at a specific time for ten days
-on the eleventh day, the rat wasn’t allowed to fight
-researchers found that the rat’s dopamine levels had raised by 65%, and his serotonin levels were reduced by 35%
-despite the fact that the rat was not fighting, the experience had changed the rat’s brain chemistry. -however, this study raises the question of whether lower levels of serotonin cause aggression or whether they are a response to aggression being carried out
-cause and effect relationship cannot be established
-substantially lowers validity of the explanation as to the causes of aggression
Limitation - beta bias is inherent in neural explanations of aggression
-Mann et al. (1990) administered the drug dexfenfluramine (which depletes serotonin in the brain) to 35 healthy adults
-researchers then used a questionnaire to assess hostility and aggression levels
-increased following administration of dexfenfluramine amongst males, but interestingly not amongst females
-shows that males and females may not be subject to the same physiological factors when explaining aggression
Strength - research support for role of testosterone
-Wagner (1979) castrated mice and aggression levels went down
-supports theory that testosterone is implicated in aggression
-however, only provides correlational support for the cause of aggression, as the research only demonstrates a relationship between lowered testosterone and lowered aggression
Outline genetic factors in aggression
-early psychologists investigating aggression believed the genetic cause of aggression could lie in the Y chromosome
-particularly interested in examining individuals with a genotype of XYY.
-these individuals were often referred to as ‘super males’ as they possessed two male Y chromosomes.
-Court-Brown (1965) discovered 314 patients that had the XYY chromosome presentation
-he put forward the view that these patients should remain hospitalised given their increased likelihood of aggressive behaviour
-more recently psychological research has focused on examining individuals with the normal XY genotype
-psychologists have used selective breeding in animals
-found that aggression is a trait that can be transmitted from parent to offspring
-hence supports genetic explanation
-research with human subjects has focused on twin studies that have looked at the incidence of aggression displayed by monozygotic (MZ or identical) and by dizygotic (DZ or non-identical) twins. -differences in concordance rates of aggression between these sets of twins have indicated that aggression has a genetic element
-advances in genetic testing in the last fifty years allowed specific genes to be identified which have been shown to carry the aggression trait down to individuals
-e.g. MAOA gene, and one variant has been named the ‘warrior gene’
-MAOA gene is responsible for the production of the protein monoamine oxidase, which allows the metabolising of noradrenaline, serotonin and dopamine
-a dysfunction in this gene can result in these neurotransmitters not being broken down in the body
-if adrenaline isn’t metabolised, then we end up with too much adrenaline
-can cause hypersensitivity in the fight or flight response and individuals may overreact to an external stimulus and perceive a threat where one does not exist
High dopamine levels = increased likelihood of feelings of reward when aggression is carried out
Low serotonin levels = lack of inhibition over impulsive behaviour
High noradrenaline levels = overreaction to perceived threats
Evaluate genetic factors in aggression
Limitation - contradictory research
-Theilgaard (1984) undertook research into men with the XYY genotype
-found that XYY can cause an increase in height in individuals but not an increase in aggression
-Coccaro et al. (1997) compared monozygotic versus dizygotic twin pairs
-in this study, twin pairs were examined for the concordance of criminal behaviour for both twins
-in cases of monozygotic or identical twin sets, the siblings are genetically identical (100% same genes) whereas in dizygotic or fraternal twin sets, the siblings are merely genetically similar (50% same genes)
-the MZ twin pairs were found to have a 50% concordance whereas DZ twins were only 19%
-supports the role of genetics in aggression as the twins that were genetically identical, i.e. 100% of the same genes, were more likely to display criminal behaviour than the twins that only shared 50% of the same genes
Strength - research support for the role of genetic factors in aggression
-scientists such as Godar et al. (2014) have refined selective breeding by specifically removing (knock-out) certain genes in mice
-has been done with the MAOA gene
-the MAOA knockout mice showed increased aggression and also higher levels of serotonin
-demonstrates relationship between genes and neurotransmitters
-when the mice were given fluoxetine to raise their serotonin levels, their behaviour returned to normal
-Brunner (1993) undertook a famous study on the males in a large family from the Netherlands, whose members were displaying high levels of aggression
-five of the males were found to have the dysfunctional version of the MAOA gene
-females in the family were not affected by the genetic dysfunction
-MAOA gene is carried on the X chromosome
-as females have two X chromosome, even if they possess the dysfunctional MAOA gene, their corresponding X chromosome is likely to have a functional MAOA gene, which has been found to be dominant
-female genotype presentation has the effect of preventing the issue of the flawed monoamine metabolism
Strength - research support
-Stuart et al. (2014) studied 97 men who had been involved in severe domestic abuse to their partners
-found the most violent men had the faulty MAOA gene
-these men engaged in the highest level of physical and psychological aggression and inflicted the worst injuries on their partners
Outline the ethological explanation of aggression, including innate releasing mechanisms and fixed action patterns
-ethological explanation seeks to understand innate behaviour of animals (including humans) by studying them in their natural environment
-focus is to try and account for behaviour in terms of its adaptive value to the specific species
-ethologists believe that by looking at animal behaviour this can help us to understand human behaviour
-aggression is also seen as providing an adaptive function by ethologists
-seen in all animal species and is believed to be an innate behaviour
-evolutionary psychologists propose that innate behaviour must be beneficial to the organism
-aggression as a behaviour can help survival, e.g. can protect resources such as land and food
-can establish dominance hierarchies, which are vital to allow access to resources, such as females.
-Lorenz (1966) proposed that aggression in animals is often ritualistic, which he argued is more adaptive than direct aggression, as symbolic aggression would help ensure the organism was not harmed
-if the organism sustained an injury as part of aggression this could impair their ability to reproduce or even result in death
-hence, ritualistic aggression such as ‘teeth baring’ would have the effect of deterring an opponent without physical harm being caused
Innate releasing mechanisms/fixed action patterns:
-believed that animals have a built-in neural structure (a network of neurons) which, when exposed to specific stimuli (signs or releasers) such as facial expressions, will cause the release of an automatic behavioural response
-inbuilt biological structure or process is called the Innate Releasing Mechanism (INR)
-the consequential aggressive behavioural sequence is called the Fixed Action Pattern (FPA)
-innate releasing mechanisms are a key part of the ethological (instinctive) approach to aggression (and other behaviours such as courtship/mating)
-e.g. when a dog sees a cat running away from them, they have an instinctive response to chase the cat
-when the cat is still the innate releasing mechanism is not activated
-when the cat runs then the INR is activated
-the chasing behaviour of the dog is an example of a fixed action patter
-the dogs desire to chase is automatic and instinctual in response to a cat or any other small animal running away from it
Evaluate evolutionary explanations of human aggression
Strength - research support
-Tinbergen (1951) undertook an experiment with male sticklebacks (very territorial and aggressive species of fish)
-in the mating season they develop a red spot on their underside
-Tinbergen observed that at this time male sticklebacks will attack another male stickleback that enters their territory
-he theorised that the red spot on their underside was acting as an innate releasing mechanism
-when one stickleback observed another stickleback with this red spot they would initiate the aggressive attack behaviour (example of a fixed action pattern)
-tested this by presenting male sticklebacks with a wooden model
-if the wooden model had a red spot, then the male stickleback would attack
-however, without the red spot the male stickleback would not react, and no aggression was displayed
Limitation - ethological explanation does not account for cultural differences
-an ethological explanation assumes that behaviour is innate
-hence, it should be uniform across all cultures
-however, Nisbett (1996) found in a laboratory experiment when South American white males were insulted, they were more likely to respond aggressively than white North American males under the same conditions
-demonstrates a high variation in aggressive responses due to cultural differences
Limitation - evidence from the animal kingdom that aggression is not always ritualistic
-Goodall (2010) studied chimpanzee behaviour for over fifty years
-observed groups of chimpanzees in brutal war against neighbouring groups of chimpanzees, slaughtering all members of the group
-she referred to this type of gang behaviour as the systematic slaughtering of one group by another stronger group
-this aggression is hard to explain from an ethological standpoint as risk of injury to the attacking group is high
-hence does not appear to be an adaptive behaviour
Limitation - contradictory research shows not all fixed action patterns are fixed
-there is some evidence that learning and environmental factors can create variation within a species
-hence it may be more appropriate to discuss modal action patterns rather than fixed action patterns. -modal action patterns are behaviours that are instinctual such as the desire to chase in dogs (the prey drive), but that differ from one individual within the species compared to others
-e.g. some dogs may chase cats but some dogs do not
-differences in behaviour may be down to training, or may be down to species differentiation as a result of selective breeding of characteristics
Outline evolutionary explanations of human aggression
-evolutionary explanation examines how behaviours that were adaptive to our human ancestors are passed down through genetic transmission from one generation to the next
-behaviours witnessed today would have evolved as a reaction to the environment 10,000 to 5 million years ago
-this time frame and environment is known as the Environment of Evolutionary Adaptiveness (EEA)
-aggression in this time would have helped an individual survive, as helps to secure resources, food, territory and women
-adaptive behaviours allowed our ancestors to survive and be more likely to reproduce and have more offspring (natural selection)
-in addition, the evolutionary explanation proposes that certain behaviours which confer an increased likelihood to survive will be sexually selected for by prospective mates
-human males would be more likely to survive if they displayed aggression as a way of protecting their mates
-this behaviour would then be sexually selected for by potential females
-aggression is also a behaviour which allowed our ancestors to establish hierarchical dominance within a group
-this dominance would result in higher status in the social group, leading to greater access to resources in general and to mates in particular
-evolutionary explanation also proposes that it would have been adaptive for human males to display aggression as a way of deterring other males from trying to steal their females
-females were a resource which allows transmission of genes to offspring
-sexual jealousy is more likely in males as males cannot ever be sure of paternity, whereas women can always be sure they are the child’s mother
-the fear that a male may be investing their resources in another male’s offspring is called cuckoldry
-evolutionary psychologists propose that aggressive sexual jealousy would be a way of avoiding cuckoldry, and would therefore provide an adaptive function
-Daly and Wilson (1966) have proposed that men have evolved mate-retention strategies to deter their mate from leaving or cheating because without a mate, the chance of passing on genes is reduced
-Two such aggressive strategies are:
1. Aggressive direct guarding – restricting her freedom to prevent males gaining access. e.g. stopping partners speaking and interacting with other men.
2. Intersexual negative inducements – issuing threats of physical violence to the female if they were interested in other males.
Evaluate evolutionary explanations of human aggression
-Shackleford et al. (2005) conducted a study where 107 married couples with an age range of 17-41 years-of-age were asked to fill in a questionnaire to assess their mate retention behaviours
-Behaviours such as direct guarding, e.g. monopolising their partner’s time and intersexual negative inducements such as threatening to punish their partner’s infidelity were measured
-extent of male retention strategies employed by the men was significantly correlated with the extent of male directed violence towards their partners
-self-report responses of both the males and females were also found to have a significant correlation ensuring the reliability of the questionnaire
-supports the evolutionary explanation that aggressive male mate retention strategies are used to deter females from committing infidelity
-however, Shackleford’s research is purely correlational
-cannot tell if the violent aggression was a result of the male mate retention strategies and not down to another third variable
-also uncertain whether the male mate retention strategies are an evolved behaviour and therefore innate
-behaviours demonstrated may have been a learnt behaviour rather than a biological response
-domestic violence has become far less socially acceptable than a hundred years ago
-this demonstrates the effect of culture and learning on aggression
-Individuals demonstrating aggressive mate retention strategies may have observed this behaviour from significant others in their lives and thus social learning could be a valid explanation for their behaviour
-difficult to separate the effects of nature from the effects of nurture when examining aggression and mating behaviour
Limitation - possible social desirability bias
-Shackleford’s research was based on self-report measures
-in many cultures it is socially desirable for a male to display aggressive behaviours
-Furthermore, Shackleford himself points out that self-report techniques suffer from issues of validity due to decay of memory over time.
-Dobash & Dobash (2000) carried out case studies of 95 women who had suffered violent abuse from their partners
-As part of the case studies they used structured and unstructured interviews, gathering both quantitative and qualitative data
-main source of conflict leading to violent attacks was reported to lie with the men’s possessiveness and jealousy
-an understanding of male mate retention strategies, however, does have practical applications, as the use of these strategies can alert friends and family to the potential for future violence
-relationship counselling can then be sought to intervene before the conflict escalates to physical violence.
Limitation - evolutionary explanations can be accused of being ‘post hoc’
-an explanation that is offered thousands of years after the behaviour would have been adaptive
-human evolution has taken over 10,000 years
-hence we cannot directly observe if this aggressive sexual jealousy is actually adaptive
-fossil evidence cannot provide us with in-depth meanings behind the behaviour of our ancestors
-furthermore, the lack of directly observable evidence also means the evolutionary explanation is not falsifiable
-in the aim of psychology to be viewed as a science it is preferable that theories and research are subject to the scientific process of falsification
-theories should be able to be proved wrong as well as right, yet an evolutionary explanation such as the explanation of aggression as an adaptive process against a threat of cuckoldry cannot be falsified as it is a post hoc explanation
Outline the frustration-aggression hypothesis as an explanation of human aggression
-put forward by Dollard et al. (1939)
-based on the psychodynamic explanation of catharsis
-Freud believed the drive for aggression was innate, like the drive for food
-thought the only way to reduce aggression is to engage in an activity which released it
-Dollard et al. (1939) proposed that if we experience frustration, this leads to aggression
-aggression is a cathartic release of the build-up of frustration
-if the individual is prevented from achieving a goal by some external factor, then this will lead to frustration which will always lead to aggression
-aggression cannot always be directed at the source of aggression, which may be abstract such as lack of money, or too powerful, as the risk of punishment is too high
-psychodynamic theory proposes we have ego defence mechanisms to protect ourselves
-two defence mechanisms that are used in the catharsis of aggression are:
1. Sublimation – Using aggression in acceptable activities such as sport.
2. Displacement – Directing our aggression outwards onto something or someone else
-Berkowitz (1969) proposed a revised frustration-aggression hypothesis, where he argued that frustration doesn’t always lead to aggression
-stated that aggression would only occur in the presence of certain cues
-e.g. cues such as the presence of weapons will be more likely to trigger aggression
Evaluate the frustration-aggression hypothesis as an explanation of human aggression
Strength - research support
-Russell Green (1968) conducted a laboratory experiment where he asked male undergraduate students to undertake a jigsaw puzzle
-while they were completing the jigsaw puzzle he organised three different conditions that were designed to raise levels of frustration in the participants
-one condition imposed an unattainable time limit to complete the jigsaw
-in another condition the jigsaw was impossible to complete
-in a third condition a confederate issued derogatory remarks to the students as they failed to complete the study
-In the second part of the study participants had the opportunity to give shocks to the confederate if he answered incorrectly on another task
-the group of participants who had experienced insults from the confederate gave the highest levels of shocks. All three groups gave more shocks than a control group who had not experienced any frustration conditions. This experiment supports the theory that frustration leads to aggression.
Strength - research support
-Berkowitz (1967) carried out a laboratory experiment where participants where again given the opportunity to shock a confederate who had previously angered them
-However, Berkowitz set up three different conditions:
-one with an aggressive cue, a gun
-one with a non-aggressive cue, a badminton racket
-one with no cue at all
-Berkowitz found those participants who were in the presence of the aggressive cue gave higher levels of shocks than the other two groups
-furthermore, this research has useful practical applications
-e.g. shed new light on the gun control debate in America
-if the presence of guns is more likely to result in aggression, then this ‘weapons effect’ could have far reaching implications for gun laws
Limitation - questionable ecological validity
-research support has mainly come from laboratory experiments
-whether the participants in laboratory experiments would carry out actual aggression when faced with an external stimulus that incited aggression is not certain
-hence findings cannot be generalised to real life situations
Outline the social learning theory as an explanation of human aggression
-aggression can be directly learned through operant conditioning, involving positive and negative reinforcement and punishment
-Bandura proposed that aggression can also be learnt by the indirect mechanism of observational learning
-social learning theory maintains that children learn through a process of imitation
-aggressive acts carried out by a role model will be internalised by an individual and reproduced in the future
-if the role model’s behaviour is seen to be rewarded, then a child can learn that this is an effective way of getting what they want
-through this process of vicarious reinforcement, rewards that are witnessed as a result of aggression result in the behaviour being seen as acceptable and then reproduced
-Bandura proposes that there are five main cognitive factors that mediate control of the aggressive behaviour:
Attention – A person/child must attend to the aggressor. So a child must pay attention to an act of aggression carried out by a role model; for instance, when a child engages in a computer game or watches a violent film they are attending to the aggression.
Retention – To model the behaviour, it needs to be placed into LTM, which enables the behaviour to be retrieved. A child needs to remember the aggression that they have witnessed.
Production – The individual needs to be able to reproduce the behaviour, i.e. have the physical capabilities. So for instance aggression displayed by superheroes is less likely to be imitated if the child does not possess the physical capabilities to actually carry out the behaviour.
Motivation – An individual must be expecting to receive positive reinforcement for the modelled behaviour. A child must expect they will get some kind of reward from carrying out aggression This doesn’t have to be materialistic but could be linked to gaining higher status in the eyes of their peers.
Self-efficacy – Individuals must believe that their behaviour will attain a goal; they must have confidence in their own ability to carry out the action and that they will be rewarded for that action. Self-efficacy relates to the factor of self-belief in one’s actions. If a child decides aggression will be an appropriate action, they must be confident that they can carry out the behaviour and that it will end up in a positive outcome.
-Bandura believed aggressive reinforcement in the form of imitation of family members was the most prominent source of behaviour modelling
-parents are the primary role models for children
-through a process of observation and identification their behaviour is modelled
-e.g. boy who watches his father attack his mother is more likely to become an abusive parent and husband
-in addition to the role models within the family, Bandura proposed that role models in the media can provide a source of vicarious reinforcement
-can lead to aggressive behaviour being replicated
-Bandura proposed that these role models can provide a child with a ‘script’ to guide their behaviour
Evaluate the social learning theory as an explanation of human aggression
Strength - several studies support the role of social learning in aggressive behaviour
-One study (1963) was conducted with three experimental conditions
-in one condition there was a filmed aggressive role model
-in another there was an aggressive role model that was a cartoon character
-in the third condition there was a real aggressive role model
-Bandura also presented a control condition with no aggressive role model
-Bandura undertook a matched pairs design where 96 children aged 3-5 were matched for baseline aggression levels
-children were then allowed to play with a toy called a Bobo doll
-and then their aggressive actions were counted
-The results demonstrated that the cartoon model produced the highest mean number of aggressive acts
-Bandura concluded that the viewing of aggression was not cathartic, but led to the modelling of the aggressive behaviour
-hence supports the social psychological explanation of the social learning of aggression.
(Check booklet for statistics)
Limitation - possible cultural bias in social learning theory
-Christianson (2006) studied the Kung San people of the Kalahari Desert
-found aggressive behaviour was very rare in this society
-Kung San parents do not use physical punishment
-there is no value placed on aggressive behaviour
-hence there are no cultural norms for aggression and children do not display aggressive behaviour
-shows the case for social learning being complex
-questions whether social learning theory in relation to aggression may only be applied to western cultures
Limitation - social learning theory can only explain some forms of aggression
-e.g. reactive aggression is harder to explain with social learning theory
-when aggression is carried out as a reaction to an external stimulus such as jealousy, pain or loneliness, this may be better explained by the frustration-aggression hypothesis rather than as a result of observational learning as proposed by social learning theory
Outline deindividuation as an explanation of aggression
-not all aggression is interpersonal, i.e. carried out from one individual to another
-some aggression is carried out in groups and is impersonal
-violence and aggression has been found to be more likely to occur when people are immersed in a crowd
-process of being part of a crowd can cause deindividuation
-Festinger (1952) coined the term ‘deindividuation’ suggesting there is a reduction of inner restraints of self-awareness where individuals are ‘submerged in a group’
-Deindividuation has been used to explain violence in prisons, and also at sporting events where large numbers of people are in close proximity to each other
-in western society we have strong norms against violence and aggression
-our identity is based on our compliance with social norms
-under normal circumstances an awareness of social norms prevents behaviour that is aggressive and deviant individuals in public places generally carry out continual self-assessment of their behaviour to ensure compliance with social norms
-however, when an individual becomes part of a crowd they become anonymous and lose their individualised sense of identity, hence loosening their normal inhibitions
-process of continual self-assessment is weakened as awareness of their individual identity is weakened. Individuals in groups do not see the consequences of any aggression and social norms that are normally followed are forgotten.
