Biological explanations of offending: GENETIC AND NEURAL

Question 1

What are the different biological explanations of offending?

Answer 1

Genetic and neural

Question 2

What is included in the genetic explanations?

Answer 2

Twin studies
Candidate genes
Diathesis stress model

Question 3

Why use twin studies?

Answer 3

It is good to use twin studies because MZ twins share 100% of their genes. If both MZ twins are more likely to be criminals than DZ twins then this supports the genetic explanation. Concordance rates reflect both greater genetic AND environmental similarity.

Question 4

Who conducted twin studies?

Answer 4

Lange
Karl Christiansen

Question 5

What did Lange do?

Answer 5

Lange (1930) investigated 13 MZ twins and 17 DZ twins where one of the twins in each pair had been to prison.

Question 6

What did Lange find?

Answer 6

He found that 10 of the MZ twins but only 2 of the DZ twins had a co-twin who was also in prison.

Question 7

What did Lange conclude?

Answer 7

Lange concluded that genetic factors must play predominant part in offending behaviour.

Question 8

What did Karl Christiansen do and find?

Answer 8

Karl Christiansen studied over 3500 twin pairs in Denmark, and found concordance rates for offender behaviour of 35% for MZ twin males and 13% for DZ twin males. This included all twins between 1880 and 1910 in a region of Denmark.

Question 9

What does Christiansen’s data indicate?

Answer 9

This data indicates that it is not just behaviour that might be inherited but the underlying predisposing traits.

Question 10

Diathesis stress model

Answer 10

A tendency towards offending behaviour may come about through the combination of genetic predisposition and a biological or psychological trigger, e.g. criminal role models or a dysfunctional environment.

Question 11

Who provides support for candidate genes?

Answer 11

Tihonen
Brunner

Question 12

What did Tihonen do?

Answer 12

Conducted a genetic analysis on 800 offenders and found abnormalities in 2 genes - found evidence of low MAOA activity and low activity from the CDH13 gene.

Question 13

What does the MAOA gene do?

Answer 13

The MAOA gene regulates serotonin in the brain and has been linked to aggressive behaviour

Question 14

What does the CDH13 gene do?

Answer 14

the CDH13 gene has been linked to substance abuse and attention deficit hyperactivity disorder.

Question 15

What did Tihonen find?

Answer 15

Individuals with this high risk combination were 13 times more likely to have a history of violent behaviour.

Question 16

What did Brunner do?

Answer 16

Brunner conducted a study on 28 male members of a Dutch family who had history of impulsive and violent criminal behaviours such as rape and attempted murder

Question 17

What did Brunner find?

Answer 17

they all shared a particular gene that led to abnormally low levels of MAOA. This is called MAOA-L.

Question 18

Who conducted adoption studies?

Answer 18

Crowe

Question 19

What did Crowe find?

Answer 19

Crowe found that adopted children whose biological mother had a criminal record had a 50% risk of having a criminal record by the age of 18, whereas adopted children whose biological mother didn’t have a criminal record only had a 5% risk.

Question 20

What do neural explanations suggest?

Answer 20

Evidence suggests there may be neural differences in the brains of offenders and non-offenders. Most of the criminals in studies into this have been diagnosed with Antisocial Personality Disorder (APD, formerly referred to as psychopathy)

Question 21

What is APD associated with?

Answer 21

APD is associated with reduced emotional responses, a lack of empathy for the feelings of others and is a condition that characterises many convicted offenders.

Question 22

What is included in neural explanations?

Answer 22

Prefrontal cortex
Mirror neurons

Question 23

Who looked at the prefrontal cortex?

Answer 23

Raine

Question 24

What did Raine discover

Answer 24

Raine has discovered that these individuals with APD have reduced activity in the prefrontal cortex of the brain, the part of the brain that regulates emotional behaviour. Put simply they find it difficult to control their impulses and do not suffer from guilt or remorse.

Question 25

What did Raine also find?

Answer 25

In 2000 Raine also found that individuals with APD had an 11% reduction in the volume of grey matter in their prefrontal cortex compared to normal controls.

Question 26

Who looks/talks about mirror neurons?

Answer 26

Keysers

Question 27

What did Keysers find?

Answer 27

Keysers (2011) found that mirror neurons did not function in individuals with APD in the same way as they do in normal controls.

Question 28

What do mirror neurons do?

Answer 28

Mirror neurons enable us to feel empathy. Individuals with APD were not completely without empathy, but had to be told to feel empathy when seeing a film showing an individual experiencing pain. It seems that these individuals are not without empathy, but can switch on or off their mirror neurons.