cb biological explanations Flashcards
what is the first biological explanation of CB
inherited criminality
explain genetic factors
inherited criminality
proposes that one or more genes predispose individuals to criminal behaviour.
where does evidence for genetic components cone from
inherited criminality
twin studies where identical (MZ) twins and non-identical (DZ) twins are compared. a higher concordance rate in monozygotic twins than dizygotic twins is evidence for a genetic basis for criminality
Adrian raine evidence (twins)
inherited criminality
reviewed research on the delinquent behaviour of twins and found a 52% concordance rate in MZ twins compared to only a 21% concordance in DZ twins
how is gene mapping linked to
inherited criminality
two genes have been particular linked to criminal behaviour
- monoamine oxidase A (MAOA)
-Cadherin 13
explain MAOA
inherited criminality
MAOA regulated the metabolism of serotonin in the brain, low levels of serotonin are associated with impulsive and aggressive behaviour.
evidence linking MAOA to criminal behaviour
inherited criminality
in the 1980s a study of 28 male members of a dutch family, that many of these male members behaved in a particularly violent and aggressive ways, and a large proportion had been involved in serious crimes of violence including rape and arson. these men were found to have abnormally low levels of MAOA in their bodies and a defect on this gene (‘warrior gene’) was later identified (Brunner et al.)
study by Tiihonen et al.
gene mapping
inherited criminality
with 900 offenders found evidence of low MAOA activity and also low activity from the CSH13 gene. they estimated that 5-10% of all violent crime in Finland is due to abnormalities in these two genes
explain differences in brain functions
inherited criminality
criminal genes may cause differences in areas of the brain or differences In key neurotransmitters.
evidence -Adrian Raine
explain differences in brain abnormalities
inherited criminality
cited 71 brain imaging studies showed that murderers, pyschopaths and violent individuals have reduced functioning in the pre-frontal cortex, the area of the brain that is involved in regulating emotion. controlling behaviour and moral behaviour in general.
lowered activity in the area is associated with impulsiveness and a loss of control
evidence- Seo)
differences in brain abnormality
inherited criminality
suggested that low levels of the neurotransmitter serotonin may predispose individuals to impulsive aggression and criminality. this is because this neurotransmitter normally inhibits (calms) the prefrontal cortex. raised levels of dopamine may enhance this effect
evidence (wright et al)
differences in brain abnormality
inherited criminality
both very high and very low levels of noradrenaline have been associated with aggression, violence and criminality. noradrenaline helps people react to perceived threats, so low levels would reduce this ability
explain diathesis stress model
differences in brain abnormalities
inherited criminality
current thinking proposes an interplay where genes are ‘switched on’ or ‘switch off’ according to environmental factors
evidence (Capsi et al)
differences in brain abnormalities
inherited criminality
conducted a study of 500 male children. researchers discovered a variant of the gene associated with high levels of MAOA and a variant associated with low levels. those with low levels of MAOA were significantly more likely to grow up to exhibit anti-social behaviour but only if they had been maltreated as children. children with high levels of MAOA who were maltreated and those with low levels who weren’t maltreated did not display anti-social behaviour
one strength of the inherited criminality explanation
twin studies and adoption studies are able to supply further empirical support to this explanation
why are adoptions useful in helping us to explore the genetic basis of a disorder?
strength of inherited criminality
people who have been adopted aren’t raised by their biological families, the influence rom their genetics is fully nature, not nurture. a differentiation between genes and environment is available
evidence to support the strength of inherited criminality
a study of over 14,000 adoptions in Denmar found that a significant number of adopted boys with criminal convictions had biological parents (particularly fathers) with criminal convictions. providing evidence for a genetic effect (Hutchings and Mednick)
what does adoption studies give to the inherited criminality explanation
validates and make the genetic explanation of criminal behaviour very difficult to argue against
significant limitation of the inherited criminality explanation
it is highly determinist. believers of this explanation suggest individuals enter a life of crime because their behaviour is controlled by internal factors that are beyond their control. they do not believe that individuals have the ability to choose how to behave and exercise their free-will.
evidence to support that inherited criminality explanation is highly determinist
(weakness of the explanation)
humans are intelligent beings capable of higher level processing which may mean that an individual chooses how to behave before they engage in a criminal act. research also shows that genes do not definitely determine criminal behaviour. Tiihonen et al. showed that those with the defective gene were 13 times more likely to have a history of repeated violence but this also shows that not everyone with the gene had gone on to become a criminal.
what implications on society does the perspective of the explanation being deterministic
is it really appropriate to punish people by placing them in prison if they have no control over their behaviour
another limitation of the inherited criminality explanation
lots of studies into the role of genetics in criminality are lacking in validity as they involve a highly biased sample. therefore the findings cannot be generalised to the overall population. male only samples cannot represent females so we are ignoring half of the population. also the males from these studies were highly unusual as they had been convicted of violent crimes which makes it difficult to draw meaningful conclusions from these studies, these individuals represent a small minority of those regularly involved in aggressive behaviour. the usefulness is highly restricted as the explanation may not be able to account for criminal activity in large groups of the population
final weakness of the inherited criminality explanation
most research relates to the association between violent and criminal behaviour.
biological explanations may just account for certain types o crime such as those involving violence and psychopathy. there os evidence that this personality trait is inherited for example; Blongien et al. found evidence to suggest that a psychopathic personality trait is inherited in looking at over 600 male and female twins
Findlay suggest?
weakness of the inherited criminality explanation
criminal behaviour includes theft, fraud drug use etc.. (these are non-violent) Findlay suggests that crime is not a ‘natural’ category it is a social construction. this makes it difficult to argue that all criminality can be explained in terms of one’s genes and their interaction with the environment
what is the second biological explanation of criminal behaviour
the role of the amygdala
what is the function of the amygdala
explanation of the role of the amygdala
amygdala was first linked to emotional behaviour by Papez and later by Maclean. it is linked to the hypothalamus, the hippocampus, pre-frontal cortex and other regions of the brain. therefore it has a widespread influence on brain functioning and so behaviours associated with emotion, motivation, social interaction in both human and non-human animals. it plays a major role in how we assess and respond to environmental threats (why it’s linked to criminal behaviour)
dysfunction in the amygdala…
lead to an individual showing aggressive and fearless behaviour. a reduction in amygdala volume has been linked to criminal behaviour
the amygdala and aggression
role of the amygdala
Coccaro et al. investigated the effects of the amygdala on aggression by studying people with intermittent explosive disorder (IED) a common symptom is outbursts of angry hot-tempered aggression. each pops views images of faces at the same time as having an fMRI on their brain.
key difference between the ups and the non-IED controls. ups with IED showed high levels of amygdala activity when they viewed angry faces. this demonstrates an association between amygdala activity and the processing of aggressive emotions.
why did Coccaro’s study have a high level of realism
angry facial expressions are an everyday signal of threat and danger
link of the amygdala and fear conditioning
biological explanation 2
Gao et al said that we learn as children to inhibit our aggression and antisocial behaviour through fear conditioning, we learn that aggressive behaviour leads to punishment of other negative outcomes.
what can a dysfunction of the amygdala lead to in terms of fear conditioning
s child would not be able to identify the social cues that indicate threat (angry faces) therefore does not link punishment to aggressive behaviour. fear conditioning will be interrupted and this individual with an amygdala dysfunction will appear fearless, overly aggressive and antisocial.
research to support amygdala dysfunction and criminal behaviour (fear conditioning)
1,795 ups were tested for fear conditioning at 3 years old. physiological arousal was used to measure the response to a painful noise (sweating)
20 years later the researchers found those who had committed crimes t age 23 had shown no fear conditioning when they were 3 years olds
they were effectively ‘fearless’ therefore suggesting a causal relationship between amygdala dysfunction and criminal behaviour
strength of the second biological explanation of criminal behaviour
empirical evidence=equal to argue against
GOspic et al. used the ultimatum game, a lab based method of measuring aggressive behaviour. it involves two players, the proposer and the responder, and a sum of money. the proposer offers to split the money in a ‘fair’ or ‘ufair’ was (unfair offer=threat)
if the responder accepts then the offer is split accordingly. but if the responder refuses the offer then both get nothing, a rejection of an offer is an interpretation of aggressive behaviour. the pps were the role o the responder while undergoing fMRI brain scans. results suggested when responders rejected unfair offers, amygdala activity was heightened and quicker. a sedative drug given before the game had 2 effects 1) it reduced aggression (halving number of rejections) and 2) reduced amygdala activity
what did Gospic et al. research show
strength of the role of the amygdala explanation
there is strong evidence for an association between reactive (hot-blooded) aggression and increased amygdala activity, and so supports proposals that the amygdala is implicated in criminal behaviour
MAtties et al.
volunteers with higher aggression scores displayed a 16-18% reduction of amygdala volumes
weakness of the role of the amygdala explanation
need to recognise the amygdala is part of a wider system of connected brain structures and does not operate on its own to determine aggressive criminal behaviour. it functions together with the orbitofrontal cortex which is thought to influence self-control, regulate impulsive behaviour and inhibit aggression
evidence to support the weakness of the amygdala explanation
Raine et al. investigated murderes who had used an overwhelming degree of reactive aggression in their crime. these individual had higher glucose metabolism (more activity in their amygdala) but abnormally low metabolism in the prefrontal cortex (which includes the OFC)
what does Raines findings demonstrate
weakness of the amygdala explanation
demonstrates how complex the regulation of aggressive criminal behaviours is. it involves at least three important brain structures (amygdala/OFC/neural connections) therefore dysfunctions in the amygdala may not be enough to count for criminal behaviour.) this explanation risks being over simplified as it only focuses on the amygdala
