Turning to crime - Biological theories

Question 1

What was the aim of Brunner et al’s study on biological theories of crime?

Answer 1

To explain the behaviour of a family in Holland where all the males were affected by borderline mental retardation and abnormal violent behaviour.

Question 2

Describe the sample in Brunner et al’s study on biological theories of crime.

Answer 2

5 affected males from the dutch family.

Question 3

What was the procedure in Brunner et al’s study on biological theories of crime?

Answer 3

Urine samples over 24 hours were collected from each participant.

Question 4

What were the results of Brunner et al’s study on biological theories of crime?

Answer 4

A point mutation was found on the x chromosome of the gene responsible for MAOA production.

Question 5

What conclusions could be made from Brunner et al’s study on biological theories of crime?

Answer 5

A defect in the MAOA gene leads to low MAOA enzyme production. This causes less serotonin to be broken down and so excessive and constant high serotonin levels cause serotonin resistance. This leads to the mental retardation/aggressive behaviour seen.

Question 6

What are 3 strengths of Brunner et al’s study on biological theories of crime?

Answer 6

+ Internally reliable procedure - objective, scientific, standardised.
+ High ecological validity - real criminals studies.
+ Ethical - no harm to PPS.

Question 7

What are 3 weaknesses of Brunner et al’s study on biological theories of crime?

Answer 7

• Low external reliability - extremely small sample of 5 - results affected by individual differences.
• Low population validity - sample not representative.
• Low internal validity - no control of activities/food, etc during the 24 hours.

Question 8

What was the aim of Raine et al’s study on biological theories of crime?

Answer 8

To measure the cortical and sub-cortical brain functioning of 41 murderers pleading NGRI using PET scans.

Question 9

What was the sample in Raine et al’s study on biological theories of crime?

Answer 9

41 murderers pleading NGRI - 39 males, 2 females.
6 with schizophrenia
23 head injuries
3 with drug abuse
3 with hyperactivity
2 with affective disorder (mood)
2 with personality disorder
2 with epilepsy

AS WELL AS 41 controls, matched on age and gender, including 6 schizophrenics. (non-murderers)

Question 10

What was the procedure in Raine et al’s study on biological theories of crime?

Answer 10

Participants were injected with a radioactive tracer (fluorodeoxyglucose) before completing a continuous performance task (CPT). The radioactive tracer is taken up by active parts of the brain and can be seen using PET scans.

Question 11

What were the results of Raine et al’s study on biological theories of crime?

Answer 11

Murderers had significantly lower activity in the:

• medial superior frontal cortex
• left anterior medial cortex
• right orbifrontal cortex
• lateral middle frontal gyri of the left and right hemispheres.
• parietal region
• corpus callosum
• left amygdala
• left medial temporal lobe
• thalamus

Question 12

What conclusions were made from Raine et al’s study on biological theories of crime?

Answer 12

• Murderers have different brain functioning to normal individuals and to psychiatric patients.

Question 13

What are 3 strengths of Raine et al’s study on biological theories of crime?

Answer 13

+ Highly scientific, repeatable procedure. Objective, standardised - internally reliable. High internal validity - cause and effect statements.
+ ethically harmless
+ Higher internal validity due to comparison with control group.

Question 14

What are 3 weaknesses of Raine et al’s study on biological theories of crime?

Answer 14

• Reductionist - only looks at biological influences of crime. Crime is a complex matter and therefore should be explained in a complex manner.
• Low ecological validity - CPT may not replicate real life situations well enough.
• Ethnocentric sample decreases population validity.

Question 15

What was the aim of WIlson & Daly’s study on biological theories of crime?

Answer 15

To examine gender and age patterns in crimes of violence.

Question 16

Describe the procedure in WIlson & Daly’s study on biological theories of crime.

Answer 16

Records of homicidal crimes in Detroit in 1972 were reviewed. The age and sex of the offenders and victims were paid particular attention to.
The data was categorised depending on the type of homicidal crime.

Question 17

What were the results in WIlson & Daly’s study on biological theories of crime?

Answer 17

Type of conflict Homicides by males Females
Social 256 83
Crime specific 161 7
Unknown 5 0
Total 422 90

Type of social conflict men women
Retaliation 84 11
Showing Off 26 3
Jealousy 25 9
Business 11 2
Family Quarrels 5 0
MIsc 32 4
Total 183 29

Homicides were mainly committed by and affected young, unmarried males. (offender AND victim).

Most homicides concerned social conflicts.

Young males were more likely to escalate trivial altercations where there is potential loss of face in front of other competing males of potential female partners.

Question 18

What conclusions were made from WIlson & Daly’s study on biological theories of crime?

Answer 18

The fact that most homicides were committed by and affected young unmarried males, and that most involved social conflict could be explained by status competition.

Therefore, their findings support an evolutionary explanation for higher crime rates in males.

Question 19

What are 3 strengths of WIlson & Daly’s study on biological theories of crime?

Answer 19

+ High population validity - ALL of the homicides in Detroit for 1972.
+ HIgh external reliability - large sample size.
+ Ethically harmless.

Question 20

What are 3 weaknesses of WIlson & Daly’s study on biological theories of crime?

Answer 20

• Low temporal validity - study from 1972, so results/findings could be outdated.
• Secondary data is used, which could be misinterpreted by researchers.
• Unscientific method, resulting in low internal validity.