Criminal Psychology Topic 1: What makes a criminal

Brunner - MAOA and Serotonin Levels

Fourteen males from one family in the Netherlands who had engaged in crimes of arson, exhibitionism, attempted r*** and assault. They were found to carry a genetic mutation on the X chromosme which meant they could not produce MAOA. 

MAOA is an enzyme which helps break down serotonin, a lack of it leads to a build up of serotonin. Serotonin is associated with aggressive behaviour so this low MAOA may increase suspectibility to anti-social traits, therefore a risk to criminal behaviour.

These findings argue that genetics (biological) rather than decision-making processes (cognitive) can influence criminal activity.

Jahoda - Self-fulfilling Prophecy

Jahoda studied delinquency rates amongst the Ashanti in Western Africa. The Ashanti people traditionally chose Kradin names for their male children, according to the day of the week they were born and that this affects temperament and has the potential for a self-fulfilling prophecy. Monday boys are thought to be placid while Wednesday boys are believed to be violent and aggressive. 

Jahoda's findings, that over a 5 year period almost 22% of violent behaviours were by Wednesday boys and 6.9% by Monday boys. Jahoda concluded that rather than confirming the Ashanti superstition, these results showed that it was the cultural expectation that selectively enhanced aspects of their development. Due to being aware of the superstition they grew up with different beliefs of themselves.

Palmer and Hollin - Moral Reasoning

A study that compared the pattern of moral development in young offenders and non offenders to see if moral development was delayed in offenders.

The sample included 123 convicted male offenders ages 13-21 and comparison of 332 non offenders ages 13-22 (210 female and 122 male). Data was gathered by questionnaires, asking about Socioeconomic status and two psychometric measures - Sociomoral Refelection Measure (SRM-SF), moral reasoning measurement and - Self Reported Delinquency checklist (SRD), levels of delinquent behaviour.

The SRM-SF showed male offenders had the least mature moral reasoning at Kohlbergs preconventional level while non offenders at conventional reasonings. Concluding having a low level of moral development could be a reason for turning to crime.

Raine et al (1997) - Brain abnormalities in muderers indicated by PET.

Relates to the question of whether brain dysfunction could be a possible reason why people might turn to crime. 

Sample - Oppurtunity sample of 41 people all charged with either murder or manslaughter (39 men, 2 women). All were pleading NGRI (reason of insanity). They all had various conditions including head injury (23), Schizophernia (6) and epilepsy (2). 

Controls - A control group with the same age and gender as them but who were not accused of anything. This meant the quasi experiment had matched participant design.

Procedure -

1) Each participant was injected with a glucose tracer. 

2) Then monitored for 32 minutes while completing a continuous performance task.

3) After 32 minutes they were given a PET scan.

Results - Suggested that murders pleading NGRI do have significantly different patterns of brain metabolism in a number of different areas.

- Reduced activity in the pre-frontal cortex. This can result in impulsivity, loss of self control, altered emotionality and an inability to modify behaviour.

- Less activity in the left side and more in the right side of the amygdala. 

- There was less activity of the corpus callosum. This could suggest an inability to grasp the long term impliciations of a situation.

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It is possible that these differnces in brain metabolism could make a person more likely to be violent. However, Raine emphasises the limitations of his own study - The result, he said, cannot be taken to indicate that violence is determined by biology alone, they do not show that the NGRI's are not responsible for their actions and they can't be generalised to other non-violent offenders.

Nature-Nurture Debate

Research can support nature - For example Brunner, Genetic mutation of the MAOA gene, lacked breakdown of serotonin, increasing aggresiveness. However explanations of crime in terms of natural factors tend to only apply to a small proportion of people.

Research can support nurture - For example Jahoda, How people are labelled changes how they behave due to a self-fulfilling prophecy. However not all people conform to the prophecy.

Research can support explanations of both nature and nurture - For example Raine, The biological factors could be explained through nurture e.g. shaking of child damamges the pre frontal cortex. However further research is needed to explain whether these two are related.

Freewill-Determinism Debate

Criminal behaviour can be determined by physiological factors - For example Brunner, they have no choice but ot be born with the lack of MAOA gene. However chose to use aggression in crime and not in sport or anything else.

Criminal behaviour can be determined by non-physiological factors - For example Jahoda, they are deermined to be born on a certain day and how they were expected to behave. However they have free-will to chose to respond to labelling as not everyone fulfills the prophecy. 

Criminal behaviour can be determined by non-physiological cognitive factors - For example Palmer and Hollin, Cognitive processes of morality was low in young offenders so were unable to process the morality of crime. However they biologically may not have been able to process this morality level.

Socially Sensitive Research

Research could lead to prejudice against groups - For example Jahoda, Through their middle name, they would be generalised to behave in a certain way. However they will most likely already know the meaning of their middle name so the information of the stereotype is not new to them.

Research could cause harm to the people involved - For example Raine (Mauritius), Children not recieving the intervention program missed out on the benefits of it in terms of improving their concentration. However at the start of the study they said they did not know the impact of the intervention would be beneficial and the level of it.

Research could cause upset to the participants - If found to have pre-conventional morality (P&H) or a lack of MAOA (B), it may assume they would commit crime in the future as they relate to the sample. However researchers could emphasise the limitations of their findings and the implications of it.

Raine's Mauritius study with Omega-3

Beginning in the early 1970's, 1795 children from Mauritius were studied. For two years, from 3 years old, 100 of the children were selected to recieve a three part intervention programme of enrichment consisting of:

1) Nutrirtion - Milk, fruit juice and a hot meal a day of fish, chicken or mutton with salad.

2) Physical exercise - afternoon sessions of gym, structured games and free play.

3) Cognitive stimulation - A miltimodal curriculum based on toys, art, drama and music.

They were compared against a control group who followed the normal curriculum with no intervention. At age 11, the children in intervention could focus their attention better and had increased level of arousal in their brains. At age 17 the children in intervention scored significantly low on conduct disorder and were less cruel to others. The effect of intergration showed a 52.6% reduction in conduct disorder. This suggested nutrituon being linked to reducing criminal levels.

The effects of smoking during pregnancy upon testosterone levels 

The higher the testosterone exposure, the longer the size of the ring finger relative to the index finger. Hence men have a relatively longer ring finger than women and why they tend to dominate, show physical advantages, have male like characteristics and have personalities linked to aggression.

Another correlation of the long ring finger is sensation-seeking and impsulsivity which is linked to anti-social and violent behaviour. People who are relatively lacking in empathy also have longer index finder, hyperactive children have a longer ring find and there is comorbidity between hyperactivity and conduct disorder. Higher aggresion is associated with longer ring fingers.

Smoking cigarettes during pregnancy can result in higher pre-natal testosterone exposure to the foetus that leaves its mark on finger length. We suspect this because mothers who smoke have higher testosterone levels and this can in turn reduce oestrogen exposure to the foetus, resulting in higher foetal testosterone levels.