There are many theories in the biological approach that explain crime. Lombroso suggests that criminals are a separate species between modern and primitive humans who had different physical defects which determined them a criminal such as a prominent jaw or a narrow sloping brow. Lombroso’s theories as a whole, but especially when applied to criminals, encourage the worst prejudices or stereotyping and have caused much embarrassment to criminologists. There is no serious evidence in its support; Lombroso’s own research was methodologically flawed.
He didn’t use proper control groups and the criminal samples he used were often mentally disturbed. However, his theory had some positive features, it was one of the first not to attribute criminal behaviour entirely to wickedness caused by a lack of will power and therefore it acknowledged that the causes of criminal behaviour cannot entirely be laid at the feet of the perpetrator. He is said to be the “Father of modern criminology” as his later theories encompass the three major strands – biology, environment and psychology.
In support of this, Sheldon suggested that there is a strong correlation between body morphology (shape) and criminal behaviour in teenagers. However, there are some contradictions to this research. The classification into the somatotypes was unreliable and the delinquent group chosen was selective. 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.