explanations of offending Flashcards
(168 cards)
what are the two biological explanations of offending behaviour?
-genetic explanations
-neural explanations
genetic explanations of offending behaviour:
-twin studies
-adoption studies
- candidate genes
how do twin studies help with our understanding offending behaviour?
they are a method for identifying a genetic basis of behaviour
method of twin studies:
-by examining monozygotic twins and dizygotic twins (who share 100% and 50% of their genetic make-up respectively), concordance rates (percentages that show how many twin pairs share the behaviour under observation) can help to indicate a possible
genetic tendency
genetic evidence from twin studies:
lange (1930)
-13 MZ twins and 17 DZ twins where one of the twins in each pair has spent time in prison were studied
10 of the MZ twins and 2 of the DZ twins had a co-twin that had also spent time in prison
christiansen (1977)
studied 87 MZ and 147 DZ twins and found a concordance rate of 35% for MZs and only 12% for DZs
↳ supports the view that offending may have a genetic component
what do the twin studies suggest?
the findings are interesting and indicate a degree of inheritance; however, the concordance rates are
low, even for monozygotic twins,
which indicates that the environment still plays a large part in criminal behaviour
what is a key criticism raised by research into genetics?
it cannot rule out the effect of the environment → a twin study may find a 68% concordance between monozygotic twins, but if they are raised in the same home environment, then the chances are that they will be treated in a similar
way by their parents/siblings and therefore the learning environment that they grow up in is likely to be a factor in their behaviour
how do adoption studies attempt to rule out environmental factors?
adoption studies attempt to rule this out environmental factors by looking at children who have been adopted and have therefore been raised by adopted parents where
there is no genetic similarity
genetic evidence from adoption studies:
crowe (1972)
compared a group of adopted children whose biological mother had a criminal record, to a control group of adopted children whose
biological mother did not have a criminal record
↳ it was found that if a biological mother had a criminal record, 50% of the adopted children also had one by the time they were 18
↳ in the control group, only 5% of the adopted children had a
criminal record by the time they were 18
this suggests that regardless of the changed environment, children seemed biologically predisposed to criminality
family studies for offending behaviour:
family studies are another way of investigating genetic links in offending behaviour
genetic evidence from family studies:
(method)
Brunner et al. (1993)
-conducted an analysis of a large family in the Netherlands, a number of which had been responsible for various counts of anti-social and criminal behaviour including attempted rape, exhibitionism and arson
genetic evidence from family studies:
(results)
-the researchers found that the males had a genetic condition (later known as “Brunner syndrome”)
-the condition results in lower intelligence levels (family had an average IQ of 85) and causes a deficiency MAOA, an enzyme
responsible for the metabolism of neurotransmitters such as serotonin
(which has links to aggression)
l
genetic evidence from family studies:
(conclusion)
-the conclusion here is that individuals can inherit genetic
conditions which make them prone to offending behaviour
-it is important to note that females only carry this condition, as it
only affects the MAOA production gene on the single X chromosome in males
exam tip:
the Brunner study can be used as an example of both genetic
and neural explanations, as both explanations can be used to justify the conclusions drawn by the researchers
genetic evidence from candidate genes:
(method)
tiihonen et al (2014)
completed a genetic analysis of 900
offenders and found abnormalities on 2 genes that may be associated with violent crime:
genetic evidence from candidate genes:
(results)
➢MAOA gene (controls dopamine and serotonin in the brain and has been linked to aggressive behaviour)
➢CDH13 (linked to substance abuse and ADHD)
→ in the sample, those with these genetic abnormalities were 13
times more likely to have a history of violent behaviour
drawback of candidate gene study:
the research hasn’t been replicated
what does the diathesis-stress model suggest about criminal behaviour?
-criminal behaviour may be genetically/biologically predisposed
but is triggered/moderated by environmental factors
-e.g. being raised in a dysfunctional environment or having criminal
role models may trigger the underlying diathesis (offending
tendencies)
↳ this is an interactionist approach
evaluation points for genetic explanations of offending behaviour:
-one limitation with using twin studies as genetic evidence is the assumption of equal shared environments
-a strength is that there is support for the diathesis stress model of crime
ao3 / limitation - one limitation with using twin studies as genetic evidence is the assumption of equal shared environments
P - one limitation with using twin studies as genetic evidence is the assumption of equal shared environments
E - it’s assumed by researchers studying twins that environmental factors are held constant because twins are brought up together and therefore have similar environments
↳ however, this shared environment assumption may apply more to MZ twins that DZ twins because MZ twins look more identical and therefore people (especially parents) tend to treat them more similarly which in turn
affects their behaviour
L - therefore, higher concordance rates for criminality in MZ twins could be due to the fact that they are treated more similarly than DZ twins
(+ one way around this is to use adoption studies, which enable psychologists to rule out the effects of the environment, since the adoptees are being raised in a different environment from the biological parent concerned
→ this helps us to see if there is any genetic link, in spite of the shared environment)
ao3 / strength - a strength is that there is support for the diathesis stress model of crime
P - one strength is that there is support for the diathesis stress model of crime
E - mendick et al (1984) studied 14427 danish adoptees and criminality (at least one
court conviction)
↳ when neither the biological or adoptive parents had a criminal convictions, the percentage of adoptees that did was 13.5% / this figure rose to 20% when either of the biological parents had convictions / and 24.5% when both adoptive and biological parents had convictions
L - this data suggests that both genetics and environment influence criminality supporting the diathesis-stress model of crime
↳ mednick’s study only applied to petty offences such as burglary, which means that any conclusions draw may not apply to more serious forms of crime
what are the key studies/ideas in the neural explanations of offending?
PFC (raine et al - 1997)
mirror neurons (keysers et al)
neurophysiology:
-frontal lobes (kandel & freed)
-amygdala → potegal et al, mitchell and blair
raine et al study: aim
to identify brain regions specific to offenders charged with murder or manslaughter, who had pleaded not guilty by reason of insanity
raine et al study: method
ppts = 41 murderers (2 female) who had been charged with murder or manslaughter and had pleaded not
guilty by reason of insanity
-the researchers used a PET scanning method to highlight areas of brain activity / these results were compared to an age and gender matched control group