BIOLOGICAL EVIDENCE - Raine et al Flashcards
Context
One of the earliest theories of criminality was Lombroso (1876) who linked facial characteristics to criminal behaviour
Argued that it is easy to spot criminals as they are not fully evolved
Atavism
He argued criminals are born not made
Studies have been done on animals where deliberate damage is done to specific parts of the brain, causing animals to exhibit highly aggressive and impulsive behaviour
People who have experienced accidental brain damage to particular parts of the brain are left with changes in behaviour and personality
Phineas Gage
Aim
Wanted to investigate whether violent criminals had brain dysfunctions in these parts of the brain
Hypothesised that there are parts of the brain that had been implicated in mental illness but were not linked to violence
Methodology
The experimental group consisted of 41 participants tried in the state of california (19 men, 2 women) with a mean age of 34.5 years
Had been charged with either murder or manslaughter but using a NGRI defence
Had to be medication free
6 were schizophrenics
A control group was formed by matching each murderer with a normal participant of the same sex and age who was to be tested using PET imaging procedure in the same lab
Mean age was 31.7
Had to be screened for health
The 6 schizophrenics were matched with 6 schizophrenics from a mental hospital
Procedures
A PET scan was used to study the active brain of both groups
When a part of the brain is active, it uses glucose, radioactive detectors can then see the radioactive areas
The participants were given the chance to practise a continuous performance task (CPT)
Designed to activate the parts of the brain that was of interest
Participants started the CPT
The radioactive FDG was then injected into each participant after 30 seconds
After 32 minutes, a PET scan was done of each participant
10 horizontal slices of the brain were recorded using the peel and box technique
Findings
Reduced activity in parts of the brain previously linked with violence
Reduced activity on the left half of the brain, increased activity on the right, particularly in areas associated with violence (hippocamus)
Parts of the brain not to been found in involved in violence had no significant difference
Conclusions
Neural processes underlying violence are complex and cannot be reduced to single brain mechanisms
Murderers pleading NGRI have different brain functioning compared to controls
This does not mean that murderers cannot be held accountable for their actions, nor that we can use PET scans to diagnose criminals
Evaluation
The researched had a lot of control ober the procedure
The PET scan allows for a wide range of non intrusive studies
Results are reliable
Scientific
A large group was involves
Sufficient people in each group for conditions to be fairly firm
X Methodological weakness - PET scans are still being developed
X The scan is a general activity task has no bearing on violent acts or even the decision to be violent
X Quasi Experiment - experimenters cannot randomly allocate participants to either of the conditions
Differences in brain activity between the groups could have been caused by other factors
X Findings only describe the brain differences but do not explain them
Alternative Evidence
Yang and Raine (2009) Meta analysis of 43 imaging studies the considered both antisocial and violent behaviour
Significantly reduced prefrontal activity in antisocial individuals
Tiihonen et al (2015) analysed genes of 895 Finnish prisoners and found an association between a gene and an increased likelihood of committing a violent crime
James Fallon analysed his own genes and found that he had the genetic and brain characteristics of a violent criminal but he wasn’t one
His positive experiences during childhood meant that his potentially criminal tendencies were not triggered
Ethical issues
Lack of valid consent - Participants were murderers that pleaded NGRI so may be not mentally competent to make the decision
Possible psychological harm - Participants may not fully understand what they have to do / what is happening (injection)
Lack of right to withdraw - Once they are not able to withdraw as they are prisoners and feel as they have no choice
Socially sensitive research
Is very reductionist
