genetic and neural explanations of OB

Question 1

what are the different components of the genetic explanation

Answer 1

twin studies (inc adoption studies)
diathesis stress and epigenetics
candidate gene studies

Question 2

what do genetic exps assume: that criminality is the result of …

Answer 2

an inherited characteristic
proposing that one or more genes predispose individuals to criminal B

Question 3

what are the examples of twin studies

Answer 3

lange
christiansen
raine

Question 4

lange twin study: investigated … MZ and …. DZ twins, where one of the twins…

they then explored how many of them…

and what did they find and what does this conclude

Answer 4

13mz
17dz

where one of the twins in each pair had served time in prison

and then explored how many of them had a co-twin who had also spent time in prison (concordance rate)

found no with cotwin in prison:
10 for mz
2 for dz

therefore suggests that genetic factors must play a predominant role in OB AND the more genes shared the more similarity in conviction

Question 5

what are limitations of lange’s twin study

Answer 5

the sample size is small and so there is a lack of generalisability

they judged whether the twins were mz/dz based off appearance and not off a dna test and so this could lead to a lack of validity. (there are some mz twins who dont look the same and so could be thought of as dz)

Question 6

christiansen explored the concordance rate of offending in mz and dz twin pairs

they had …. mz pairs and …. dz pairs
concordance rates were…

and what does this support the view of…
but what is the problem with these results

Answer 6

87 mz pairs , ccr = 33%
147 dz pairs, ccr = 12%

supports he view that OB may have a genetic component

BUT you would expect mz twins to have a higher if not 100% ccr and so this suggests that other factors have a role and it isnt due to genetics entirely

Question 7

raines twin evidence, raine reviewed delinquent B of twins and found what ccr for mz and dz

what are limitations of this

Answer 7

mz ccr- 52%
dz ccr- 21%

delinquent b is very broad and so this was not operationalised, so the difference in rates could be due to type of delinquency/how it was measured, delinquent not necessarily convicted so the difference could be due to convicted vs not

the sample was also very small so cant necessarily generalise

Question 8

what are general lims of twin studies: cant separate

Answer 8

the role of genetics and the E and MZ have a more similar E and so this doesnt represent how others see the world, dz because they look different they may be treated different and so that could be a reason the ccr was less as they have more different experiences

Question 9

what are the examples of adoption studies

Answer 9

crowe
mednick

Question 10

mednick studied … adoptees and looked at their risk of OB

what was the % of adopted sons who went on to be criminals

Answer 10

with both adoptive and bio parents having criminal convictions: 24.5%

bio crim parents- 20%

crim ad parents- 15%

neither bio nor ad parents had criminal convictions- 13.5%

Question 11

what are lims of mednick

Answer 11

they didnt look at daughters and so by not separating this is could act as confounding variable, ie results could be because sons offend more than daughters.

only petty crime was studied so cant generalise to serious crime

Question 12

what did crowe find- adoption study

adoptees risk of having a criminal record by age 18 for having either a biological or adoptive parent with a criminal record

Answer 12

biological- 50% greater risk
adoptive- 5% risk

suggests that inherited genes are a marginally more significant factor than E influences

Question 13

what are the lims of adoption studies

Answer 13

adoption could happen at any ages, the reason for adoption could be because the parent is in prison, could still be eg visiting biological parent, more traumatic when older &raquo_space; E factors

cant separate all factors so assumes the role of genetics and the E

Question 14

what is research into candidate genes all about

Answer 14

searching genome wide, not family based, for certain genes that predispose an individual to ob

Question 15

who provides evidence for candidate genes

Answer 15

brunner
tilhonen

Question 16

tilhonen- a finnish study of …. offenders found evidence of abnormalities (…..) on two genes that may be associated with …….

what are the genes and what do they control in relation to ob

Answer 16

900 offenders
low activity
violent crime

MAOA gene- which controls serotonin and dopamine and is thought to be linked to aggressive B

CDH13 gene- thought to be linked to substance abuse and attention deficit disorder > impulsive > dont think about consequences/lack of inhibition > ob

Question 17

tilhonen- those with …… were …. times more likely to have a history of repeated …

Answer 17

defective genes
13x
violent behaviour

high risk combo

Question 18

tilhonen- estimated that between … - … % of all violent crime in finland may be due to …..

Answer 18

5-10%

abnormalities in the MAOA and CDH13 genes

Question 19

limitation of tilhonen:

Answer 19

not be replicated so dont know whether its valid or not

Question 20

brunner: researched … male members of a … family with a history of .. and … criminal Bs such as … and ….

brunner analysed the … of these men and found that they shared a particular gene that led to abnormally low levels of …

Answer 20

28
dutch
impulsive and violent
rape and attempted murder
dna
MAOA

Question 21

what does the diathesis stress model suggest with regard to OB

Answer 21

it is the modern understanding of genetic influence

no longer 1 or few genes on their own will determine ob. tendency towards ob may come through the combo of genetic predisposition and bio or psych trigger

eg being raised in a dysfunctional E or having criminal role models

Question 22

what is the role of epigenetics in the diathesis stress model of crime

Answer 22

proposes an interplay where genes are “switched on or off” by epigenomes- which in turn have been affected by E factors

this can exp lack of CCR in mz

Question 23

where does evidence for diathesis stress model come from

Answer 23

caspi and mednick

Question 24

caspi used data from a …. study in NZ that has followed …. people from where they were babies in the ….
they assessed …..B at age 26

they found …% of those men with low ……. had experienced ….. when they were babies but were responsible for …..% of violent convictions

Answer 24

longitudinal
100
1970s

antisocial B
12%
low MAOA genes
exp maltreatment
44%

so maltreatment is an e trigger that causes maoa gene to be switched off

Question 25

general lims of genetic explanations

Answer 25

lims with supporting research evidence for violent crime but not non violen criminality not 100% explained

Question 26

apply determinism to genetic exp

Answer 26

determinist- no free will, legal system based on the premise that criminals have a personal and moral responsibility for their crimes, and only in extreme mental cases can someone plead they werent acting under their own free will. this raises ethical issues with what soc does with people who are suspected of carrying criminal genes and implications for sentencing

Question 27

apply reductionism to genetic exp

Answer 27

reductionism- wrong to reduce down to genetics because it is actually multiple factors interacting, criminality is complex, criminality does appear to run in families, but so does emotional instability and mental illness for eg, this makes it difficult to untangle the effects of genes and neural influences from other possible factors

Question 28

what are the components of the neural exp of OB

Answer 28

regions of the brain mirror neurones neurotransmitters

Question 29

what is APD

Answer 29

antisocial personality disorder (formerly psychopathy) and most evidence for neural exp comes from offender with ADP. characterised by lack of empathy, reduced emotional responses, and it characterises many criminals

Question 30

what is the evidence regions of the brain: raine cited ... brain imaging studies showing ... also raine found ...% reduction in prefrontal cortex

Answer 30

71 showing offenders (murderers, psychopaths, violent individuals) have decreased functioning in the prefrontal cortex 11% reduction in volume of grey matter in prefrontal cortex of people with APD compared to controls

Question 31

what is the prefrontal cortex involved in

Answer 31

regulating emotion and controlling moral B, a decrease in activity = impulsiveness and loss of control

Question 32

what is the evidence regions of the brain: raine found that ... who were found .... limbic system

Answer 32

murderers who were found not guilty by insanity, compared to control, were found to have abnormal asymmetries in limbic system, especially the amygdala having reduces activity on the left and increased on the right

Question 33

what is the limbic system responsible for

Answer 33

it is a set of subcortical structures including the hypothalamus, amygdala. it is linked to emotion and motivation

Question 34

what are mirror neurones

Answer 34

an exp that says that criminals with APD can exp empathy but more sporadically then everyone else christian keysers found that criminals could empathsise when asked to (when shown a video of a person in "pain") and this activates an empathy reaction suggesting APD can have a neural switch controlled by mirror neurones whereas a normal brain has empathy permanently on

Question 35

what is the evidence for neurotransmitters: serotonin, seo suggested that ..

Answer 35

low serotonin levels predispose individuals to impulsive aggression > ob, this is because low S > lack of inhibition of impulsive aggressive urges by the prefrontal cortex dopamine hyperactivity may enhance this effect

Question 36

what is the evidence for neurotransmitters: noradrenaline

Answer 36

very high OR very low noradrenaline levels is associated with aggression, violence and criminality (Wright) very high: causes activation of the sns and the f/fr which leads to aggression very low: reduces ability to react to perceived threats

Question 37

what is the evidence about the relationship between brain injury and criminality

Answer 37

is it commonly observed that criminals report having some head injury (in general 8.5/% of the US pop have a brain injury compared to 60% in US prisons (harmon) therefore brain differences may be due to nurture, or they may be inherited (nature)

Question 38

strength of neural exp: rwa, methods of treatment

Answer 38

if low serotonin levels are related to increased aggressiveness in criminals, could be given special diets that enhance their serotonin and so aggression is decreased artificial sweeteners are high in phenylalanine and low in tryptophan both of which make the production of serotonin difficult therefore this suggests that drugs and or changes in diet could be used to help some individuals

Question 39

limitation of neural exp: it is based on research into aggression rather than OB (what are the impacts of this generally in terms of the use of the research)

Answer 39

eg for studies into neurotransmitters it is aggressiveness being studied NOT criminality so validity is reduced. also some studies use non-human animals which undermines the potential relevance of the info in relation to understanding OB also with genetic evidence, there is not 100% correspondence with any of the brain or neurotransmitter. therefore the data cannot be used to predict who might become an offender and the research cannot be generalised to non-violent crimes

Question 40

limitation of neural exp: issues about c +e, one issue is about whether abnormalities

Answer 40

one issue is about whether abnormalities in regions of the brain or levels of neurotransmitters are the cause of OB, the result of OB or just an intervening variable. research only highlights a correlation between head injuries and later criminality. eg someone who grew up in a violent household might be more likely to suffer head injury, so the link between head injury and OB could be because of a violent childhood therefore neural exps only highlight an association not a causal link with crime