BIOLOGICAL EXPLANATIONS : GENETIC AND NEURAL Flashcards
genetic explanations of crime suggest
would be offenders ingerit a gene, or combo of genes taht predispose tehm to commit a crime
importance of genes illustrated through
twin studies
in terms of Twins and adoption studies who did christiansen study
over 3.5k twin pairs
in denmark
what did christinasen find in his twin strudies
3 points
concordance rates for offender behaviour 35% MZ males
13% for DZ males
slightly lower rates for females
CHristiansens study included tqwins born between
1880
1910
in a region of denamrk
in christeansesn study the offender behaviour was checked against
danish police recvords
offender behaviour was checked against poli records what did the data indicate
not jst behaviour that may be inherited
but the underlying predisposing traits
what did crowe find in his adoption study
adopted kids , bio mother , have criminal record, 50% risk of having a crimnal record by 18
adopted kid , mum no crim record , got 5 % risk
CANDIDATE GENES - genetic anlysis of * finnish offender found
800
two genes may be associated with violent crime
CANDIDATE GENES - what were teh two genes thought to be associated with violent crim in the genetic analysis
MAOA
CDH13
CANDIDATE GENES - what does MAOA gene do and has been linked to
regulate serotonin in brain
aggressive behaviour
CANDIDATE GENES - what has CDH13 been linked to
substance abuse
attention deficit hyperactivity disorder
CANDIDATE GENES - what did the genetic analysis find
5-10% of all sever violent crime in findland is attributed to MAOA and CDH13 genotypes
DIATHESIS STRESS MODEL - if genetics have influence on offending , it seems likely this may be partly moderated by
effects of the enviro
DIATHESIS STRESS MODEL - how may a tendency towards offending behaviour come about
combo of genetic predisposition and a biological or psychologial trigger such as growing up in a dysfunctional enviro / ahving criminal role models
NEURAL XPL - evidence suggests there may be * differenceas in brains of
neural differences
in breains of offenders compared to non offenders
NEURAL XPL - much evidence of neural differences has involved individuals diagnosed with
Anti social Personality Disorder
APD formerly known as
psychopathy
what is APD associated with 2
reduced emotional responses
lack of empathyfor feelings of others
apd is a condition that charcatersies many
convicted offenders
PREFRONTAL CORTEX - rain conducted manys tudies of APD brain - what did he report
theres several dozen brain imagign studies showing
individuals with APD have reduced activity in prefrontal cortex
what is prefrontal cortex associatged with
part of brain that regulates emotional behaviour
alongside finding reduced activity in prefrontal cortex what else did raine find
11% reduction in ovlueme of grey matter in prefrontal cortex of people with APD compared to controls
MIRROR NEURONS - What does recent research suggest
offenders with APD can experinece empathy but do so more sporadically than the rest of us
MIRROR NEURONS - what did keysers find and how
only when offedners were asked to empathise (with a person on film xp pain)
did their empathy reaction (controleld by mirror neurons in brain) activate
MIRROR NEURONS - what does keysers study suggest
APD indi not totally without empathy
but may have a neural switch that can be turned on and off
unlike normal brain which has empathy switch permanently on
eval - bio deterministic
criminaality too complex to reduce to genetic or neural level
lots of thing seem to run in families such as poverty and social deprevation
therfore difficult to disentagle oall of possible influences on offending behaviour
furthermore CR in twin studies never 100% - meaning enviro factors may be at least parlty responsible for criminal behaviour
so for example diathesis tress model could be better explanation for criminal behaviour where CR for MZ twins not 100%
strength - gentic explanations - diathesis stress model - research support
researchers did study on over 13,000 adoptees
foun when neither the biological nor adoptive parents had convictions the % of adoptees that did was 13.5 %
found when either of bio parents did went up to 20%
wennt up to 25% when both parents had a conviction
shows genetic inheritance plays an important role but environmental influence cannot be disregarded
providing support for diathesis stress model of crime
weakness - twin studies- limitation assumption of equal enviro
studies tend to asume twins raised in equal enviro as twins generally raised together limitation
however could apply to much more to MZ than DZ twins
as people - ptclry parents tend to treat MZ twins more similarly than DZ
This therfore impacts behaviour
so higher CR could be result of them being treated same rather than due to genetics - which is a confounding variable for this research
weakness - adoption studies
presumed seperation of genetic and enviro influences (- whihc is whole point of adoption studies )complicated by fact many kids xp late adoption so much of childhood could have been spent with bio parents anyway
similarly lots of adoptees maintain reg conctat with bio parents following adoption
this makes it difficult to assess the relative impact of biology on offending behaviour
therfore assessing relative impact of nature/nurture may only be possible with very early adoptions where contact with biological relatives dont occur oherwise contact with bio relatives is a confounding varibales
STRENGTH NEURAL XPL - research support - brain evidenc
one strength of the neural explanation is support for the link between crime and frontal lobe
Kandel and Freed reviewed evidence of frontal lobe damage and antisocial behaviour
people with such damage tended to show impulsive behaviour, emotional instability and an inability to learn from their mistakes
the frontal lobe is associated with planning behaviour
this supports the idea that brain damage may be causal factor in offending behaviour
limitation - neural - intervening variables
one limitation of the neural explanation is the link between neural differences and APD may be complex
other factors may contribute to APD, and ultimately to offending
Farrington et al studied a group of men who scored high on psychopathy (APD)
these men had experience various risk factors during childhood, such as being raised by a convicted parent and being physically neglected
it’s possible that these early childhood experiences cause APD and also some of the neural differences associated with it - such as reduced anxiety in the frontal lobe due to trauma
this suggests that relationship between neural differences , APD and offending is complex and there may be other intervening variables that have an impact
