5.4. Biological Explanation

Question 1

Genetic: Christiansen

Answer 1

Looked at 3500 twins -> 35% Mz and 13% dz concordance rate = must be a genetic element

Question 2

Genetic: Crowe

Answer 2

Adoption studies -> if a child has a criminal mother, they have a 50% risk factor of being a criminal compared to 5% for children with no criminal parents.

Question 3

Genetic: Tiihonen

Answer 3

• Found candidate genes responsible for criminal behaviour = violent only
• MAOA -> links to aggressive behaviour
• CDH13 -> links to substance abuse
• They regulate serotonin

Question 4

Genetic: diathesis stress

Answer 4

• Diathesis: genetic predisposition
• Stress: an environmental stress that triggers the criminal behaviour -> epigenetics turn on the criminal gene like a switch

Question 5

Neural: noradrenaline

Answer 5

Increased noradrenaline leads to violence and aggression

Question 6

Neural: serotonin

Answer 6

Decreased serotonin leads to impulsive behaviour

Question 7

Neural: testosterone

Answer 7

Increased testosterone leads to violence and aggression

Question 8

Neural: Anti social personality disorder

Answer 8

• Decreased resting HR, low activity in pre frontal cortex, birth complications that damage the brain, mother smoked/ drank during pregnancy -> leads to APD
• They lack empathy and have a decreased emotional response

Question 9

General discussion

Answer 9

• The definition of crime changes but this explanation is fixed
• Doesn’t explain all crime, just violent and aggressive crimes

Question 10

Genetic strength: Medrick

Answer 10

• Looked at 13,00 adoptees with 1 conviction
• 13.5% - with biological or adoptive parent with no convictions
• 20% -one biological parent had a conviction
• 24.5%- both biological and adoptive parent had a conviction

Question 11

Genetic weakness: twins

Answer 11

It’s hard to disentangle nature from nurture, they are socialised the same, could equally be explained by SLT (observe and imitate role models), the same is true for observing criminal parents

Question 12

Genetic weakness: adoption studies

Answer 12

Many extraneous variables
- Age of adoption
- Contact with family
- Small sample sizes
—-> hard to tell what is nature and what is nurture so lacks scientific control

Question 13

Neural strength: Kendal

Answer 13

• Researched people with frontal lobe damage
• Found their behaviour was impulsive and they were emotionally unstable, also they couldn’t learn from their mistakes
• This is a casual factor that may explain offending but not cause it

Question 14

Neural weakness: Farrington

Answer 14

• Studied adult males with APD who had a convicted parent and were physically neglected as children
• This is an environmental cause, not biological
• Other factors need considering