Biological Explanations of Offending Behaviour: Genetic and Neural

Question 1

What is the MAO-A gene explanation?

Answer 1

-A mutation of the monoamine oxidase A: MAO-A gene.
- MAO-A is associated with violent criminal behaviour.
- Normally, the MAO-A gene is responsible for producing an enzyme that breaks down serotonin and dopamine.
● The MAO-A variant slows the rate of this breakdown and will produce abnormal levels of
neurotransmitters which could impact upon anti-social behaviour and offender behaviour.

Question 2

A03 - Biologically Deterministic - Includes Tiihonene

Answer 2

• The explanation could be criticised for being too biologically deterministic.
  -Whilst the variant is associated with increased probability of criminal conviction, not all
  with the variant engage in criminal behaviour.
• For instance, the MAO-A variant explanation is supported by Tiihonene et al’s (2015)
  findings that people born with a MAO-A gene variant were 13 times more likely to have a
  history of repeated violent behaviour. However, this means that some with the MAOA gene variant did not become offenders.
  ● This means that the genetic explanation is questionable as a comprehensive
  explanation for all criminal activity.

Question 3

A03 - Research by Caspi - Switching on and off genes

Answer 3

• Research suggests that MAO-A variant may be activated by particular environmental
  experiences.
• Caspi et al. (2002) suggested that offending behaviour did not simply require an MAO-A
  gene variant, but that the environment that they grew up in switched on and off various genes that also contributed to the behaviours.
• Epigenetics focusses on the interaction between genes and environmental experiences.
  -Genes can be switched on or off in reaction to experiences and environmental factors.

-For example, it is suggested that maltreatment during childhood or having criminal role
models acts to switch on/off genes that encourage behaviours linked with criminal
behaviour.
- This is in line with the diathesis-stress model.

Question 4

A03 - Research by Mednick

Answer 4

Support for criminal behaviour arising from the interaction of genes and the environment
comes from Mednick et al (1984).
- They followed over 13000 adoptees who had at least one criminal conviction.
-When neither of the biological or adoptive parents had a conviction, 13.5% of adoptees
did.
-When either of the biological parents had a conviction, the rate rose to 20%.
- When both the biological and adoptive parents had a conviction this again rose to 25%.

• This suggests that although genetic inheritance plays an important role in offending,
  environmental influence must also be acknowledged.
• Hence, as an explanation of criminal behaviour, the diathesis-stress model is supported.