Aggression Flashcards
what is aggression?
refers to a range of behaviours that can result in both physical and psychological harm to oneself, others or objects in the environment.
how can aggression be expressed?
verbally, mentally and physically.
what are the two types of aggressive behaviour?
proactive (cold-blooded) and reactive (hot-blooded) aggression.
what is proactive aggression (cold-blooded)?
a response in anticipation of a reward, predatory and calculated, it is a planned method of getting what you want e.g. robbery.
what is reactive aggression (hot-blooded)?
a response to a perceived threat, fear based, hostile and impulsive in nature, usually in retaliation e.g. revenge porn.
what is included in the neural mechanisms in aggression?
the limbic system and the orbitofrontal cortex and serotonin.
what is the limbic system?
a group of structures inside the brain that are associated with emotions.
what key role does the limbic system play?
it plays a key role in how an organism responds to environmental threats and challenges - therefore believed to be the key factors in whether we respond aggressively or not to an external stimulus.
what is the papez-maclean limbic theory?
it is an explanation of aggression involving structures such as the amygdala, hypothalamus and hippocampus which are implicated in reactive aggression.
what is the role of the amygdala?
it controls reactions to fear, anger and other emotional responses - amygdala activity increases in response to angry faces (social provocation).
what did gospic et al (2011) do?
illustrated amygdala activity and some participants were subjected to mild provocation.
what did gospic et al (2011) find?
when participants reacted aggressively, fMRI scans showed a fast and heightened response by the amygdala.
what did a benzodiazepine drug taken before the provocation lead to?
it reduces arousal of the ANS - when taken before the provocation it led to 2 effects: decreased the activity of the amygdala and halved the number of rejections (reduced aggression) - illustrating the role of the amygdala.
what is the orbitofrontal cortex and what does it link with?
it is in the frontal lobe and has a role in decision-making.
- it links with the amygdala to act as a braking system on wrong thoughts and decisions.
what is the role of serotonin?
it works on the frontal areas of the brain to inhibit the firing of the amygdala (calming influence) - acts as a brake.
what does low levels of serotonin mean?
there is no brake so people can’t control their impulsive and aggressive behaviour so aggression is more likely.
what did goodwin find in his study of vietnamese marines who showed overtly aggressive behaviour?
they were found to have abnormally low levels of serotonin.
what did animal studies on monkeys find?
those with low serotonin showed anti-social behaviour/personality traits.
what did mann et al (1990) do?
administered the drug dexfenfluramine (which depletes serotonin in the brain) to 35 healthy adults and a questionnaire was used to assess hostility and aggression levels.
what did mann et al (1990) find?
it led to increased hostility and aggression amongst males but not females.
what did mann et al (1990)’s findings lead to?
the issue of beta bias that is inherent in neural explanations of aggression and shows that males and females may not be subject to the same physiological factors when explaining aggression.
what is a strength of neural mechanisms of aggression?
berman et al (2009) gave participants a placebo or a dose of paroxetine and then took part in a lab-based game involving electric shocks in response to provocation and they found that they paroxetine group consistently gave fewer and less intense shocks meaning that this study is evidence of a causal link between serotonin function and aggression.
what is a weakness of neural mechanisms of aggression?
according to caccaro et al (2007), OFC activity is reduced in psychiatric disorders that feature aggression and this reduced activity disrupts the OFC’s impulse-control function, causing aggressive behaviour which shows that the neural regulation of aggression is more complex than theories focusing on the amygdala suggest.
what is included in the hormonal mechanisms in aggression?
testosterone and progesterone.
what is testosterone and its role?
it has a role in regulating social behaviour via its influence on certain areas of the brain implicated in aggression - it peaks in males during adolescence and declines with age and is implicated in aggression.
what did dabbs et al (1987) do and find?
measured testosterone levels in saliva in violent and non-violent young male criminals and found that high testosterone levels were positively correlated with more violent crime; rule violations in prison and parole board decisions against release.
what did castration studies of animals show?
removing the testes (source of testosterone) reduces aggression in the males of many species and giving injections of testosterone to the same animals resotres aggressive behaviour indicating that testosterone has a role in aggression.
what did dolan et al (2001) find?
a positive correlation between testosterone levels and aggressive behaviours in a sample of 60 offenders (men) in max security hospitals and these men mostly had personality disorders and histories of impulsively violent behaviour.
what is progesterone and its role?
levels of progesterone vary during the ovulation cycle and are lowest during and just after menstruation - evidence suggests that progesterone plays an important role in aggression in women.
what did ziomkiewicz et al (2012) find?
a negative correlation between progesterone levels and self-reported aggression which suggests that low levels of progesterone are linked to increased aggression in women.
what is a strength of hormonal mechanisms in aggression?
giammanco et al’s (2005) review of studies confirms the role of testosterone e.g. in male monkeys there is an increase in both testosterone levels and aggressive behaviour during the mating season, in rats - castration of males reduces testosterone and also mouse-killing behaviour and injecting female rats with testosterone increases mouse-killing which show the role of testosterone in a range of animal species.
what is a weakness of hormonal mechanisms in aggression?
carre and mehta (2011) developed a dual-hormone to explain why there is mixed evidence of the link between testosterone and aggression in humans, they claim that high levels of testosterone lead to aggressive behaviour but only when levels of cortisol are low and when cortisol is high, testosterone’s influence on aggression is blocked, therefore the combined activity of testosterone and cortisol may be a better predictor of aggression than either hormone alone.
what are genetic factors?
genes consist of DNA strands - DNA produces ‘instructions’ for physical features which may impact psychological features, genes are transmitted from parents to offspring.
what are twin and adoption studies used for?
to investigate genetics and aggression (concordance rates).
what did twin studies find?
genetic factors account for around 50% of the variance in aggressive behaviour (how much the variation in aggressive traits is due to genetics, the rest is the environment).
what did coccaro et al find?
concordance rates of 50% for MZ twins and 19% for DZ twins for aggression (direct physical assault).
what did adoption studies find?
similarities between the adopted child and their biological parent suggests a genetic influence e.g. rhee and waldman found genetic influences accounted for 41% of the variance in aggression.
what are specific genes and an example of them?
particular genes or variations of genes which may lead to aggressive behaviour, the MAOA gene has been identified (one variant).
what is the MAOA gene responsible for?
the production of the enzyme monoamine oxidase which breaks down noradrenaline, serotonin and dopamine.
what can dysfunction in the MAOA gene result in?
neurotransmitters not being broken down in the body (metabolised).
what happens if adrenaline is not metabolised?
too much adrenaline - hypersensitivity in fight or flight response; individuals may overreact to an external stimulus.
what happens if dopamine is not metabolised?
increased/excessive dopamine - feelings of reward more likely when aggressive.
what happens if serotonin is not metabolised?
too much serotonin - aggression.
what did lea and chambers (2007) do?
nicknamed the MAOA gene the ‘warrior gene’ which showed that the MAOA-L variant was possessed by 50% of new zealand maori men (compared with 34% of caucasions), maori people have had a reputation of being fierce.
what did brunner et al (1993) do and find?
studied 28 men from a large duton family who were repeatedly involved in impulsively aggressive violent criminal behaviours and these men had abnormally low levels of the enzyme MAOA as well as the MAOA-L gene variant.
what is significant about gene-environment (GxE) interactions
MAOA-L gene activity is only related to adult aggression when combined with early traumatic life experiences.
what did frazzetto et al (2007) find?
association between higher levels of antisocial aggression and the MAOA-L gene in men, only in those who had experienced significant trauma during their first 15 years of life - this is strong evidence of a gene-environment interaction (sometimes described a diathesis-stress).
what are the strengths of genetic factors in aggression?
stuart et al (2014) studied 97 men who had been involved in severe domestic abuse to their partners and they found that the most violent men had the faulty MAOA gene, they engaged in the highest level of physical and psychological aggression and inflicted the worst injuries on their partners.
mertins et al (2011) had men with the MAOA-L and MAOA-H genes take part in a money-distributing game, they found that men with the MAOA-H variant were more co-operative and made fewer aggressive moves than the low-activity participants which supports the relationships between MAOA gene activity and aggression.
-> (counterpoint): found that even participants with the MAOA-L variant behaved co-operatively rather than aggressively when made aware of others’ behaviour, therefore genes are influenced by environmental factors that are at least as important in aggression.
what is a weakness of genetic factors in aggression?
in every pair of twins, both individuals share the same environment as each other but DZ twins may not to the same extent as MZ twins, it is assumed that they do (equal environments assumption), but this assumption may be wrong as one aspect of environment is the way twins are treated by others - MZ twins treated very similarly while DZ twins in less similar ways, this means that concordance rates are inflated and genetic influences on aggression may not be as great as twin studies suggest.
what is ethology?
the study of animal behaviour (including humans) in their natural environment.
what is the ethological explanation of aggression?
aggression is innate behaviour that has an adaptive function i.e. can aid survival (protect resources such as land and food) and can establish dominance hierarchies (vital to allow access to other resources, such as females).
what did petit et al (1988) do?
studied groups of young children and observed how aggression played an important role in the development of dominance hierarchies, this would be adaptive (and thus naturally selected) because dominance over others brings benefits.
what did lorenz (1966) believe?
that aggression is innate in all species - it is not learned and it is mainly genetically determined.
what did lorenz (1966) propose?
aggression in animals if often ritualistic, which he argued is more adaptive than direct aggression, as symbolic aggression would help ensure the organism was not harmed.
what is ritualistic?
a series of behaviours carried out in a set order.
what is an innate releasing mechanism (IRM)?
a built-in neural structure (a network of neurons) which, when exposed to specific stimuli (signs or releasers), will cause the release of an automatic behavioural response (a fixed action pattern).
what is a fixed action pattern (FAP)?
consist of a series of actions triggered by key stimulus, the pattern will go to completion even if the stimulus is removed.
what are the 6 main features of FAPs (according to lea (1984))?
- stereotypes or unchanging sequences of behaviours.
- universal (same behaviour found in all species).
- unaffected by learning (regardless of experience).
- ‘ballistic’ - once behaviour is triggered, it follows an inevitable course and cannot be altered before it is completed.
- single-purpose, behaviour only occurs in a specific situation.
- a response to an identifiable specific sign stimulus.
what are the key assumptions about aggression?
- ethologists study aggression in non-human animals and then apply findings to humans because they believe that we are all subject to the same forces of natural selection.
- aggression can be the result of an evolved automatic biological response in the brain - innate releasing mechanisms leading to fixed action patterns.
what did tinbergen (1951) do?
presented sticklebacks with a series of wooden models of different shapes (male sticklebacks are highly territorial during the mating season and when they develop a red spot, if another male enters their territory a sequence of highly-stereotyped aggressive behaviours is initiated (FAP)).
what did tinbergen (1951) find?
- regardless of shape, if the model had a red spot the male stickleback would aggressively display and even attack it.
- no red spot = no aggression
- these aggressive FAPs were unchanging from one encounter to another, once triggered, the FAP always ran its course to completion without any further stimulus.
what is a strength of the ethological explanation of aggression?
brunner et al’s study (1993) showed that MAOA-L gene is closely associated with aggressive behaviour and twin and adoption studies also showed that there is a significant genetic component to aggression in humans, these pieces of research point towards an innate basis to aggressive behaviour suggesting that the ethological approach is correct in claiming that aggression is genetically determined, heritable and adaptive.
-> (counterpoint): nisbett (1993) found that 1 type of homicide was more common amongst white men in southern USA than in the northern and he concluded that the difference was caused by a ‘culture of honour’ in the southern which suggests that this reactive aggression comes from a learned social norm rather than being instinctive, therefore culture can override innate predispositions, which is hard for ethological theory to explain.
what are the weaknesses of the ethological explanation of aggression?
goodall (2010) observed a ‘4-year war’ during which male chimps killed all the members from another group in a systematic way, the violence continued even when the victims offered signals (which did not inhibit aggressive behaviour as predicted by ethological explanation) which challenges the ethological view that same species aggression has evolved into a self-limiting and relatively harmless ritual.
hunt (1973) pointed out that FAPs are actually influenced by environmental factors and learning experiences, an FAP is typically made up of several behaviours and the duration of each varies, therefore patterns of aggressive behaviour are much more flexible than lorenz thought.
what is the evolutionary explanation of aggression?
it explores how behaviours that were adapted to our human ancestors were passed down (genetically) through generations.
- it suggests that aggression serves as an important function in terms of both individual survival as well as reproductive potential.
what is environment of evolutionary adaptiveness (EEA)?
the time frame and environment in which human traits evolved (bowlby).
