Zusammenfassung der Ressource
Biological explanations
of offending
- Genetics
- Twin studies
- Compare
concordance rates of
MZ (identical) and DZ
(non identical) twins.
- If the offending
behavious is
genetic expectd
that there would
be higher
concordance rates
for MZ than DZ
twins
- Lange - found that concordance
rates for DZ twins was 77% and for
MZ twins was 12%.
- However Christiansens study was better
controlled and he found that MZ twins
had only 35% concordance rates and 12%
for DZ,
- Early twin studies were not well
controlled as there was no way to tell
wether twins were MZ or DZ except to
guess.
- Twins reared apart often attended
the same schools and visited each
other regularily.
- Adoption studies
- Involve comparing the
criminal futures of adopted
children with their biological
and adoptive parents.
- If there a greater degree of
similarity between Biological
parents and the children then
criminality has a genetic
basis
- Almost 50% of children in a sample
of adopted children whose biological
parent had a criminal record,
themselves had a criminal record by
the time they were 18. In a matched
control group where mothers didn't
have a criminal record, only 5% where
convicted of criminal offences.
- Hutchings and Mednick- Found that
if both Adoptive and biological
parents had a criminal record,
32.6% of sons became criminals, if
only adoptive father was a criminal
11.5% sons were criminal and if
neither parents had a criminal
record only 10.5% became
criminals
- Children who are
adopted tend to be
placed in a similar
enviroment to their
biological parents
- Some children are
adopted at a much
later age so it may
be early childhood
experiences that
cause criminal
behaviour.
- Andrews and Bonta- Common
criminality of biological parent and
adopted child may be solely due to
the effect of inherited emotional
instability or mental illness rather
than directly inherited criminality.
- No single criminal gene
has been found
- Both twin and adoption
studies seem to support genetic
component but they do also
indicate that the enviroment
may also play a role as even MZ
twins do not have 100%
concordance.
- Chromosones
- Has been an attempt to link
criminal behaviour to the
possession of an extra Y
chromosone
- Atypical chromosones
- The Y chromosone is responsible for
male sexual development and
testosterone which has been linked to
aggression.
- In 1965, Jacobs et al claimed
to discover the atypical
chromsone pattern XYY in
1.5% of prison population as
opposed to only 0.1% in
normal population
- Within et al - found
that only 12 out of
4500 had the extra Y
chromosone and none
had a criminal record.
- The XYY theory is no longer acceptable
- They are both
reductionist
explanations
attempting to reduce
offending behaviour
down to chemicals and
cells