Brain injuries / disorders

• Brain injuries and disorders are associated with changes in behaviour.
• Prefrontal cortex: emotional processing, conflict between rational and emotional choices
• Parietal lobe: cognitive control, IQ
• Occipital lobe: subcortical structures, septum
• Temporal lobe: hippocampus, monitors and controls aggressive behaviours, amygdala
• Many studies have found links between structural brain abnormalities and psychopathy. Damage to the orbital cortex, just above the eyes, and the front part of the temporal lobe (the amygdala), which is responsible for animal drives.
• Raine et al (1994) used PET scans to study the living brains of impulsive killers and found damage to their prefrontal cortex (this is the part that controls impulsive behaviour).
• A case study of brain damage would be Phineas Gage, who after a traumatic brain injury, turned from the kind, soft-spoken man he was into a vulgar and irresponsible man, who had to be kept from women and children.
• A serial killer afflicted by brain injury would be Earle Nelson, who received a traumatic brain injury after an accident on his bike, that left him in a coma for 6 days. His behaviour was reportedly never the same after that.
• A strength of brain injuries / disorders theory would be that, in a few extreme cases, as supported by real life incidents and research studies, certain damage to parts of the brain has been associated with criminality.
• A strength of brain injuries / disorders would also be that there is a correlation between abnormal EEG readings (brainwave activity measurements) and psychopathic criminality.
• Prisoners are more likely to have a brain injury than non prisoners.
• A limitation of brain injuries / disorders would be that crimes caused by brain injury or disease are actually very rare. The offender's original personality is typically more important in predicting future criminality than changes to this; for example, the killing or mutilation of animals in childhood.
• Another limitation of brain injuries / disorders would be that it is unclear whether abnormal EEG patterns are a cause of criminality. Some psychopaths show these signs, whilst others do not.
• A final limitation would be that the fact that more prisoners have brain injuries than non-prisoners could in fact be because of their criminality, due to fights or injuries sustained during the act itself.