Biological Explanations:Genetic And Neural

Question 1

What do genetic explanations suggest about offenders?

Answer 1

Offenders inherit a gene or combination of genes that predispose them to crime

Question 2

In Christiansen’s study of twins, what were the concordance rates for offender behavior?

Answer 2

• 35% for identical twins (MZ)
• 13% for non-identical twins (DZ)

Slightly lower in females

Checked against danish police records, indicating that its both the behaviour and the predisposing trait that’s inherited

Question 3

What was the sample population of Christiansen’s twin study?

Answer 3

All twins born between 1880 and 1910 in Denmark

in over 3500 sets of twins

Question 4

What did Crowe’s study reveal about adopted children with a criminal mother?

Answer 4

50% chance of having a criminal record by age 18

Question 5

What is the chance of adopted children without a criminal mother having a criminal record by age 18?

Answer 5

5%

Question 6

What did Tilhonen’s genetic analysis suggest about violent crime?

Answer 6

Two genes (MAOA and CDH13) may be associated with violent crime

suggested in his analysis of 800 finnish offenders

Question 7

What role does the MAOA gene play?

Answer 7

Regulates serotonin and is linked to aggressive behavior

Question 8

What is the association of the CDH13 gene?

Answer 8

Linked to substance abuse and ADHD

Question 9

According to Tilhonen, what percentage of severe violent crime in Finland is attributable to MAOA and CDH13?

Answer 9

5-10%

Question 10

What does the Diathesis-Stress Model suggest about the role of genetics and environment?

Answer 10

A combination of genetic predisposition and environmental triggers contribute to behavior

These environmental triggers can be biological or psychological

Question 11

What factors might contribute to criminal behavior according to the Diathesis-Stress Model?

Answer 11

• Dysfunctional environment
• Criminal role models

Question 12

What evidence suggests neural differences in offenders?

Answer 12

Differences in the brains of offenders and non-offenders, particularly with antisocial personality disorder (APD)

Question 13

What is a characteristic of antisocial personality disorder (APD)?

Answer 13

Reduced emotions and lack of empathy

Question 14

What did Raine’s studies reveal about the prefrontal cortex (PFC) in individuals with APD?

Answer 14

Reduced activity in the PFC and an 11% reduction in grey matter volume

Question 15

What is the function of the prefrontal cortex (PFC)?

Answer 15

Regulating emotional behavior

Question 16

What recent findings suggest about empathy in offenders with APD?

Answer 16

can experience empathy but do so sporadically

Only when asked to empathise did their empathy reaction activate

• suggests people with APD have a neural switch (mirror neuron) that can be switched on or off
• ‘normal’ brain always has it switched on

Question 17

What is a limitation of twin studies?

Answer 17

Equal environment assumption

Researchers think twins brought up together, experience the same environmental factors
- May apply more to MZ twins than DZ due to the same appearance = same treatment = affecting behaviour
- higher concordance rates in MZ may be due to similar treatments than DZ

Question 18

What is a limitation of adoption studies?

Answer 18

Aims to separate nature from nurture

Adopted children may still experience influence of biological parent

Adoption mostly take place in childhood = already spent time with bio parents also adoptees encourage to keep in contact with bio parents
- means bio parents can still exert an environmental influence

Question 19

What is a strength of diathesis-stress model?

Answer 19

Evidence supports it: 13,000 danish adoptees studied by Mednick et al
The percentage of adoptees with convictions increased with criminality in biological or adoptive parents

Shows genetic inheritance and environment plays an important role in offending

Question 20

What were the percentages of adoptees with convictions based on parental criminality?

Answer 20

• 13.5% when neither parent (bio/adoptive) had convictions
• 20% when either parent (bio OR adoptive) had convictions
• 24.5% when both parents (bio/adoptive) had convictions

Question 21

What is a strength of the neural explanations regarding crime?

Answer 21

Evidence supports the link between crime and frontal lobe damage

Kandel and Freed reviewed evidence of frontal lobe damage (including PFC) and antisocial behaviour

Question 22

What behaviors tend to be exhibited by individuals with frontal lobe damage?

Answer 22

• Impulsiveness
• Emotional instability
• Inability to learn from mistakes

Question 23

What role does the frontal lobe play in behavior?

Answer 23

Responsible for planning behavior

Shows that brain damage may be a causal factor in offending behaviour