What makes a criminal? Flashcards
Reasons for criminal behaviour
- Brain dysfunction
- Mental health issues
- Addictions
- Genetics
- Surroundings (SLT)
Brunner’s Aim
Use gene linkage analysis to follow a single gene through a particular family to track a disorder and provide a genetic explanation for crime.
Brunner’s Sample
Large dutch family where many of the men had a history of criminal behaviour.
Brunner’s Procedure
Analysed urine samples over 24 hours, indicated enzyme production and any genetic mutations.
Brunner’s Results
Mutated gene on the X chromosome lowering the production of MAO-A enzyme. This meant serotonin and adrenaline were not being broken down properly.
What Brunner’s study suggested
Increased levels of serotonin and adrenaline linked to aggressive and deviant behaviours explaining crime.
Caspi’s Aim
To look into the effects of upbringing along with the decreased levels of MAO-A
Caspi’s Sample
500 male students from New Zealand
Caspi’s Results
Found that students who had low levels of MAO-A were significantly more likely to be antisocial, this was enhanced by a damaging environmental upbringing.
Suggestions made after Caspi’s study
That there is an interaction between genes and the environment that determine aggressive behaviour
Farrington’s Aim
Investigate whether problem families produce problematic children. Such as divorced parents and siblings with convictions
Farrington’s Sample and Procedure
411 London boys aged 8 up until they were 46, longitudinal. The boys were interviewed as well as mothers and teachers.
Farrington’s Results
Those who were more exposed to more problems became more problematic. He argued there to be a cumulative effect as individually had a small effect.
Farrington’s risk factors
- Divorced Parents led to lack of a role model
- Family with other convictions led to imitated behaviour
- Poor eduction meant they can’t provide for themselves
- Malnutrition means poor cognitive development
Farrington suggestions
That many environmental factors can lead to a prediction of criminal behaviours
Farrington Pro’s
- Longtidudinal so no individual differences
- Large sample
- Interactionist with parents and teachers
- Ecologically valid
Farrington Con’s
- Low generalisability, androcentric
- Ethnocentric
- Reductionist
- Social desirability bias
Raine’s Aim
Analyse levels of brain dysfunction using PET scans of murders who have pleaded NGRI
Raine’s Sample
41 murderers matched with 41 non murderers, based on age, gender and schizophrenia. Also kept drug free for 2 weeks. Was a quasi experiment.
Raine’s Method
Used a PET scanner and injected harmless radioactive material. Asked to do continuous performance tasks for 32 minutes. The radioactive material bonds with glucose but its left behind after its used indicting patterns of activity.
Prefrontal Cortex
Emotional expression, understanding implications in a situation
Amygdala
Processes fear in the brain
Parietal Cortex
Controls verbal ability and education levels
Raine’s Results
- Less activity in prefrontal cortex in murderers, less emotional expression
- Less activity in parietal cortex meaning lower verbal ability
- Less activity in the Amygdala so less able to process fear
What Raine’s research suggested
That brain dysfunction may be a contributing factor to violent criminal behaviours.
Pros of Raine’s research
- High control of extraneous variables
- Useful applications
- Objective quantitate data
- Standardised procedure
- Ethical as its a quasi
Con’s of Raines research
- Taken of drugs could be ethical issue
- Ecological validity
- Socially sensitive
- Lacks generalisability
- Lacks qualitative data
- Reductionist
Application of Biological Strategies
Raine created a three part intervention programme based on Nutrition, Physical Exercise, Cognitive Stimulation. Found that intervention reduced crime by what he argued as 35%. Follow up study also showed omega 3 supplements reduced aggression.
