Criminal Psychology

Psychiological explanations of criminal behaviour-

e.g Lombroso's criminal characteristics 

Sheldon's 3 criminal body types (Endomorph, Mesomorph, Ectomorph)

Hereditary factors (genes) that may predispose individuals to the risk of criminal behaviour; 

low activity in the prefrontal cortex 

Research done by Raine- The role of twin and adoption studies. 

Non-physiological explanations of criminal behaviour- 

e.g social explanations- upbringing parenting, poverty

learning explanations- operant, classical conditioning, social leaning. 

Sutherland's differential association hypothesis; cognitive explanations such as moral development  (Kohlberg)

Brain abnormalities in murderes indicated by positron emission tomography

Damage to the pre-frontal cortex may result in impulsivity, immaturity. altered emotioniality, loss of self-control and the inability to modify behaviour. All lead to aggressive acts.

Amygdala- associated with aggressive behaviour and the recognition of emotional stimuli such as fearful expression on someone's face. Damage to the amygdala is associated with 'fearlessness'. 

The amygdala is a set of neurones locared in the medial temporal lobe. Forms part of limbic system and plays key role in processing of emotions. 

The limbic system made up of the amygdala, hippocampus and pre-frontal cortex governs the expression of emotion. 

With the thalamus, these areas are important in learning, memory and attention.

Abnormal functioning in there areas may lead to problems such as not being able to form conditioned emotional resposes and failure to learn from experiences. 

One particular group of violent offenders are those who plead not guilty by reason of insanity- (NGRI) 

The hypothesis in this study is that seriously violent individuals have localised brain damage in a varity of regions: the prefrontal cortex, angular gyrus, amygdala, hippocampus, thalamus and corpus callosum. 

PET scan-  detects metabolism level in injected substances (such as glucose) made mildly radioactive to show which parts of the brain are most active 

Raine used PET scans to discover whether there are brain abnormalities in murderers who plead NGRI. 

If significant differences can be found between the patterns of glucose metabolism in the brains of such individuals compared to those of non-murderers the correlation might indicate that they're more prone to violence. 

Until this study, no previous brain imaging had been conducted to either support or refute this notion.

Natural, quasi experiment because of the IV- whether the participant was a murderer pleading NGRI or 'normal' (taking no medication and with no history of psychiatric illness, except for 6 scizophrenics who were selected to match 6 schizophrenic murderers)

DV- whether participants showed evidence of dysfuntion in their prefrontal cortex and other areas such as angular gyrus, amygdala, hippocampus, thalamus and corpus callosum which had previously been linked to violent behaviour. 

Matched participants design- matched with age and gender. 

6 schizophrenics is experimental group were matched with 6 schizophrenic murderers. 

Experimental group- 41 participants, tried in the state of Calfornia. Charged with murder or manslaughter. 

Had been transferred there because 

(1) to obtain evidence as to whether they were NGRI

(2) to find out whether they were competent to understand the judicial process

(3) to see whether there was any evidence of diminished mental capacity that might affect the nature of the sentence they recieved. 

Referred for reasons such as, Schizophrenia. head injury, pschoactive drug abuse, affective disorders, epilepsy, learning disability, personality disorders. 

Thermoplastic head holder- individuallt moulded so participants' head could be still when being scanned. 

PET machine to image brain functioning 

Flueorodeoxyglucose (FDG) tracer injected to trace brain metabolism.

Degraded stimulus version of a continuous performance task (CBT)- ask to detect target signals for 32 mins. To make the frontal lobes work

Procedure-

All offenders were medication free for 2 weeks prior

10 mins in- before injection- started CBT practise trials 

32 seconds before FDG injection- started real CBT 

32 mins after FDG injection- participant referred to adjacent PET scanner room 

PET scanner took 10 slices (pics) at 10mm intervals to be obtained in relation to differences in brain metabolism in both 6 main cortical areas (outside brain) and 8 sub-cortical areas (inside brain) 

Murderers pleading NGRI have significant differences in the metabolism of glucose in the number of brain areas compared with non-murderers. 

The study identifies some specific psychological processes which may predispose some criminals to violent behaviour. 

Recuced activity in the prefrontal, parietal and callosal regions of the brain, together with asymmetries of activity in the amygdala, thalamus and medial temporal love, including the hippocampus, may be one of many predispositions towards violence in murderers pleading NGRI. 

This reduced activity in the prefrontal areas may explain impulsive behaviour, a loss of self-control, evidence of immaturity, altered emotionality and the inability to modify behaviour. 

Social experiences, situational factors, psychological predispositions and learned responses also play a part. 

Brain dysfuntion may be a result of violence 

Not all violent offenders have brain dysfunctions. 

At least one biological strategy for preventing criminal behaviour- 

e.g  plastic surgery for prisoners to improve their appearance, making them look less 'criminal'; participation by pregnant women in health and nutrition programmes to reduce antisocial behaviour in their offspring; the use of drugs to reduce violent behaviour