Jacobs suggested that men with the XYY syndrome were more aggressive than normal XY men. There are 15 sufferers per 1,000 in prisons and 1 per 1000 in general public. However, as the research was a correlation study, it can’t establish cause and effect. Although it proved some correlation between the XYY chromosome and aggression, it cannot say one causes the other.
Raine carried out a cognitive task which involved sustained attention. It used PET scans on violent killers and had them watch a screen for 32 minutes and responding every time a zero appeared. It was found that the impulsive killers missed many of the zeros. Damage was also found in the prefrontal cortex which controls impulsive behaviour. Findings suggested that low physiological arousal, birth complications, fearlessness and increased body size are early markers for later aggressive behaviour. The study strongly suggests that damage to the prefrontal cortex may be related to violence. However, it was pointed out that the defects found could be linked to psychotic drug use, hyperactivity or epilepsy, which are all present in criminals. It was also suggested that prefrontal cortex damage may interact with environment and social influences for example; poverty, unemployment, school failure which may predetermine towards criminal behaviour.
The psychodynamic approach can explain crime in terms of the 3 ways in which the super ego can lead to criminal behaviour. The superego can lead to criminal behaviour depending how it developed. The superego punishes the ego with anxiety when an immoral act is contemplated and with guilt if the act is carried out. A weak superego is developed as a result of abnormal relationships within the family which would result in a person acting in ways to gratify their id regardless or the social restraints on doing so. A deviant superego is developed during the phallic stage, their superego can develop deviant values if the same sex parent is deviant too for example a son may develop a deviant superego if his father is a criminal.
A strong superego can leave a person feeling anxious and guilty since every time they act on the id’s desires their superego would punish them for it. This could result in a person committing crimes in order to get caught and punished to eliminate the guilt imposed by their own superego. Alternatively, a strong superego might prevent the person from expressing any of their antisocial impulses that inevitably build up in their unconscious. This could lead to a sudden overwhelming of the ego and could be expressed violently as murder or rape.
However, psychodynamic theories of offending are no longer widely accepted by psychologists, for a number of reasons. Firstly, it is difficult to test as the theories heavily rely on concepts such as the unconscious mind, which existence is difficult to prove. Secondly, psychodynamic researchers heavily depend on qualitative case studies in which the subjects’ behaviour is interpreted in symbolic terms. This is a highly subjective process as it is possible to draw different conclusions from the same case study depending on the researcher. Although, it is important not to overlook the positive contributions that psychodynamic theories have made to criminological psychology. Researchers have pointed to the importance of childhood experiences and parent-child relationships as an influence of offending and have identified many important variables relating to delinquent behaviour in adolescence. In support of this is Bowlby’s case study on children. He said that the ability to perform meaningful social relationships in adulthood was dependent on a close, warm relationship with the mother. If disrupted future relationships would be impaired. He found that 39% of a group of juvenile delinquents had experienced significant disruption to their attachments compared to 5% of a non delinquent group. But it’s important to note that Bowlby’s study was a case study therefore findings from his case study are only applicable to that individual or group and not generalisable to the public.
The behaviourist approach has theories which explain criminal behaviour such as Bandura’s SLT theory of aggression as it suggests that behaviour of all kinds is learned through observation. If a model is observed acting aggressively, and is then rewarded then imitation is likely. If a model is punished, then imitation becomes less likely. To support this, his Bobo Doll study focused on Children’s aggression after they observed an adult acting different ways towards a doll and the children were then allowed to play with the doll. However, because it was a lab experiment it doesn’t predict that’s how children would act in real life so it lacks ecological validity. Also, the children would’ve known that it wasn’t a real person therefore any aggression towards the doll isn’t applicable to humans.
Although in support of Social Learning Theory, a natural experiment examined children’s level of aggression before and after the introduction of television into an isolated community. It was found that over a 2 year period aggression in the community children had rose steadily whilst in a similar community where there was already television, there was no increase.
