Inherited criminality

Question 1

Predisposition

Answer 1

A greater likelihood that something will happen.
Examples -
Genetic predispositions may make it more likely that an individual displays certain traits.

Question 2

Monozygotic twins

Answer 2

Identical twins.
Twins from one zygote.

Question 3

Dizygotic twins

Answer 3

Non-identical twins.
Twins from two zygotes.

Question 4

Concordance rates

Answer 4

A measure of genetic similarity.
In a sample of twin pairs, one twin of each pair has a disorder.
The number of times their other twin also shows the disorder determines the concordance rate.

Question 5

Raine (1993)

Answer 5

Twin studies comparing identical (MZ) and non-identical (DZ) twins show higher concordance rates in the first group.
52% VS 21%

Question 6

Brunner (1993)

Answer 6

Analysed the DNA of 5 male members of a Dutch family with a history of violent crime.
Found they all had a gene that leads to abnormally low levels of MAOA.

Question 7

MAOA

Answer 7

Monoamine oxidase A.
An enzyme that, among other things, regulates levels of serotonin in the brain.

Question 8

Tiihonen (2015)

Answer 8

900 violent offenders.
Found evidence of low activity from the CDH13 gene as well as low MAOA activity.
They concluded that up to 10% of violent crime in Finland may be due to abnormalities in these two genes.

Question 9

Epigenetics

Answer 9

Refers to the material in each cell of the body that acts like a set of “switches” to turn genes on or off.

Question 10

Diathesis-stress

Answer 10

Modern understanding of genetic influence no longer proposes that one or even a few genes on their own will determine behaviour.
Instead current thinking in terms of epigenetics proposes an interplay where genes are “switched” on or off by epigenomes which in turn have been affected by environmental factors.

Question 11

Caspi et al (2002)

Answer 11

Used data from the longitudinal Dunedin study that has followed about 1,000 people from when they were babies in the 1970s.
Caspi et al assessed antisocial behaviour at age 26.
Found that 12% of those men with the low MAOA gene had experienced maltreatment but were responsible for 44% of violent convictions.

Question 12

Differences in the brain

Answer 12

Reduced functioning in the prefrontal cortex - linked to violent crime.

Question 13

Raine

Answer 13

Carried out a meta-analysis - murderers, psychopaths and violent criminals have lowered activity in the prefrontal cortex. Associated with impulsiveness and loss of control.

Question 14

Seo et al

Answer 14

Suggest that low levels of serotonin predispose individuals to impulsive violent behaviour, partly because serotonin inhibits the prefrontal cortex.

Question 15

Wright et al

Answer 15

Suggest the same effect appears to be caused by very high and very low levels of noradrenaline. Noradrenaline helps people react to perceived threats.

Question 16

Raymond Crowe (1972)

Answer 16

Found that adopted children who had a biological parent with a criminal record had a 38% greater risk of having a criminal record by the age of 18 whereas adopted children whose mother didn’t have a criminal record only had a 6% risk.

Question 17

Sara Mednick et al’s (1987)

Answer 17

14,000 adoptees found that 15% of sons adopted to a criminal family went on to be criminals compared with 20% whose biological (but not adoptive) parents were criminal.
This suggests that inherited genes are a more significant factor.

Question 18

Explaining non-violent crimes

Answer 18

Most of the genetic (and neural) research on criminal behaviour relates to the association between criminal and violent or aggressive behaviour.
At best, biological explanations may just account for certain kinds of crimes such as those involving violence and also psychopathy - a psychopath is a person who lacks empathy with what other people feel.
They’re therefore more likely to commit crimes.

Question 19

Bruce Blonigen et al (2005)

Answer 19

Found support for genetic basis looking at over 600 male and female twins.

Question 20

Lynn Findlay (2011)

Answer 20

Suggests that crime is not a “natural” category - it doesn’t exist apart from how we choose to define it.
People have created the category of criminal behaviour and it includes many different types of crime.
This makes it difficult to argue that such a behaviour can be simply explained in terms of genetics and its interaction with the environment.

Question 21

Problems with determinist explanations

Answer 21

Genetic explanations are presented as if the genes a person is born with determines later behaviour.
The law asks the question about whether the cause of behaviour is outside a person’s control.
It’s harder for some individuals to avoid criminal violence - and this may be due to both their biology and the environment they grew up in.
Therefore a determinist view of criminal behaviour can’t be totally ruled out.

Question 22

Tiihonen et al (2015)

Answer 22

Those with the defective gene were 13 times more likely to have a history repeated violent behaviour, but this means that not everyone with the gene had become a criminal.

Question 23

Brain differences: cause or effect?

Answer 23

In order for genes to cause criminal behaviour, they must be linked to a physical or psychological effect.
One possibility is differences in the brains of criminals.

Question 24

Harmon (2012)

Answer 24

8.5% of the US population have had a brain injury compared with 60% in US prisons.