Biological Explanations: Genetic and Neural Explanations Flashcards
Lange date
1930
Lange studied
13 MZ and 17 DZ twins where one of the twins had been sent to prison
Lange - ten of the MZ twins had a co-twin who was also in prison but
this was only true for two of the DZ twins
Crowe date
1972
Crowe found that adopted children who had a biological parent with a criminal record had a
50% greater risk of a criminal record by the age of 18
Crowe also found that adopted children whose mother didn’t have a criminal record only had a
5% risk
Tiihonen et al
2014
Tiihonen et al conducted a genetic analysis of
900 offenders
Tiihonen et al found
two genes that may be associated with violent crime
what are the two genes that Tiihonen et al identified?
The MAOA gene.
The CDH13 gene.
having a weakness in both the MAOA gene and the CDH13 gene led to individuals being
13 times more likely to have a history of violence
if genes have an influence on offending,
this influence is likely to be at least partly moderated by environmental factors
a tendency to criminal behavior may come about through a combination of
Genetic predisposition.
A biological or psychological stressor or trigger
antisocial personality disorder
there may be neural differences in the brains of criminals and non-criminals
antisocial personality disorder is associated with
Lack of empathy
many criminals suffer with
antisocial personality disorder
Raine et al date
2000
Raine et al found an
11% reduction in the volume of grey matter in the in the prefrontal cortex of people with antisocial personality disorder compared to a control
the prefrontal cortex controls
emotional behavior
Keysers date
2011
Keysers found that only when criminals were asked to emphesise
they showed an empathy reaction
because antisocial personality disorder do show emotions
this shows that sufferers are capable of emotion but they have a switch which turns them on and off
in a normal functioning brain, the switch is always
on
Lange research was
poorly controlled
most twins are raised
in the same environment so concordance rates may be due to shared learning experiences rather then genetics
methodological issues such as confounding variables mean
twin studies of criminality may lack validity
Mednick et al date
1984
Mednick et al studied
13,000 Danish adoptees and criminality
Mednick et al found that when neither the biological nor adoptive parents had convictions
only 13.5% received a conviction during their lifetime
the percentage rose when either of the parents had a conviction
20%
the percentage rose further when both of the parents had a conviction
24.5%
Mednick et al percentages
Neither parents - 13.5%
Either parents - 20%
Both parents - 24.5%
Madnick et al conclusion
the data suggests that both genetic inheritance and environment can influence criminality
Madnick et al conclusion means that the results support
the diathesis-stress model of crime
adoption studies are complicated by the fact that
many children experience late adoption
some children taken away from their parents still remain
in contact with them
because children can be taken away later and can still stay in contact with their biological children
it makes it difficult to assess the environmental impact that the biological parents might of had
criminality is complex
explanations that reduce offending behavior to a genetic or neural level ignore higher levels of explanations
crime runs in families but so does
Poverty.
Deprivation.
Mental illness.
because things like crime and poverty run through families, it makes it difficult to
disentangle the effects of genes and neural influences from other factors
because its difficult to disentangle genes and neural influences from other factors, it indicates that
genetic and neural explanations in isolation are too simplistic
