Neural Explanations of Offending Behaviour

An alternative way of looking at the biological causes of offending behaviour is to examine neurochemical (neurotransmitters) and neurophysiological underpinnings.

Neurotransmitters and Offending Behaviour

Two key neurotransmitters are seen to have a role in offending behaviour:

• Serotonin – this neurotransmitter has been inked to mood and impulsiveness.
  • Moir and Jessel (1995) cite a number of human and animal studies which suggest a link between low levels of serotonin and aggression, which is linked to criminal behaviour.
  • Scerbo and Raine (1993) conducted a meta-analysis on 29 pieces of research into anti-social adults and children, finding in all cases, low levels of serotonin.
• Dopamine – has been identified as it is linked to the dopaminergic pathway, which results in pleasure, which is a rewarding feeling and a desire to repeat certain behaviours. This is why dopamine has been linked to addiction and substance abuse, and therefore through this it has an indirect link to criminal behaviour.
  • Buitelaar (2003) found that juvenile delinquents given dopamine antagonists which reduce levels of dopamine, showed a decrease in aggressive behaviour.
  • Couppis (2008) argues that some individuals who engage in certain criminal behaviours may experience an increase in dopamine and as a result seek out such experiences again due to the reward feeling.

Neurophysiology and Offending Behaviour

Specific parts of the brain have been highlighted as important in terms of criminal behaviour, including:

• Amygdala – the amygdala is part of the limbic system, which is regarded as an older region of the brain in an evolutionary sense; therefore, it comes as no surprise that many of the structures within the limbic system are seen to have some sort of survival benefit. The amygdala in particular has been identified as a structure with links to emotion regulation and aggression.
• Frontal lobes – the frontal lobes, part of the neocortex (neo being “new” in an evolutionary sense), have been linked to higher function such as social behaviours and planning.
  • Brower and Price (2001) found a link between frontal lobe dysfunction and violent crime.
  • Kandel and Freed (1989) looked at frontal lobe damage and anti-social behaviour, finding that there was a tendency for such individuals to exhibit emotional instability, a failure to consider the consequences of their actions or to adapt their behaviour in response to external cues. These traits would seemingly be a result of impaired functioning in the frontal lobes, a region responsible for planning behaviour.

Key Study: Raine et al. (1997)

Aim: To identify brain regions specific to offenders charged with murder or manslaughter, who had pleaded not guilty by reason of insanity.

Method: The participants were 41 murderers (2 female) who had been charged with murder or manslaughter and had pleaded not guilty by reason of insanity. The researchers used a (positron emission tomography) PET scanning method to highlight areas of brain activity and these results were compared to an age and gender matched control group.

Results: They found reduced activity for the offender group in areas such as the prefrontal cortex and corpus callosum (the nerve fibres responsible for swift communication between the hemispheres). Additionally, there were abnormalities in the activity of the limbic system, including the amygdala and thalamus.

Conclusion: There is indication that offenders (specifically violent offenders) have abnormal brain function when compared to normal controls. As there is largely reduced activity, it would suggest that the brains of offenders are slowed and perhaps unable to make the swift decisions to react appropriately in certain situations. For example, the frontal lobes are linked to planning behaviour; therefore, perhaps the decreased prefrontal cortex activity indicates that offenders are unable to consider the consequences of their actions and control their behaviour.

Evaluation of Neural Explanations

The neurochemical explanations of offending behaviour have been criticised for being overly simplistic. The links between abnormal levels of a certain neurotransmitter and offending behaviour, often centre around violent and aggressive behaviour, which does not explain all types of crime. This is important because it lacks the complexity necessary to understand why individuals commit crimes such as burglary or drug dealing, which aren’t necessarily violent or aggressive in nature.

The nature of some of the research into neurochemistry and neurophysiology is often correlational, which means that there is no clear way to show cause and effect. For example, the low levels of serotonin found in offenders could be a cause of offending behaviour, but they could also be the effect of it. Similarly, the structural brain abnormalities found in Raine et al. (1997), could be a cause of offending behaviour or the result of some environmental factor, which in turn makes them more likely to become a criminal. This matters because it highlights the complexity of the relationship between biology and behaviour and suggests that further investigation is required.
One criticism of neural explanations of offending behaviour is that they can be considered reductionist. For example, where researchers look at the way a neurotransmitter or brain region might contribute to offending behaviour, they are overlooking other important factors, such as how the environment might have an impact on these areas as well. That being said, such researchers will argue that to be reductionist allows a more straightforward investigation to be conducted as it would be nearly impossible to disentangle all of the possible explanations and their interactions and investigate them scientifically.This is important to consider as while reducing complex behaviour to its simplest form does require researchers to overlook key factors, it is also essential for good scientific practice.

Critical Thinking

Nature or nurture? A key debate in the discussion of offending behaviour is whether it is a result of nature or nature. The evidence above presents the case for nature, but arguments from the nurture perspective should not be ignored and the interaction between the two should not be overlooked. For example, Lombroso’s theory and research had clear implications for the criminal justice system. If offenders are, as Lombroso argues, not responsible for their crimes then how should they be punished, particularly if they cannot control their actions due to their physical make up?

Free will and criminal responsibility. An important issue with any area of research such as this is that if we conclude that biology is a key part of offending behaviour, then there is a question mark over who is criminally responsible. To view offending behaviour as biologically predetermined is seen as deterministic, since the argument follows that such an individual is determined by an internal factor, in this case genetics/physiology. If that is the case, as Lombroso argued, can they be held responsible for their crimes, since they are unable to control their biology? In this instance, the case of Charles Whitman is a thought provoking one. On 1^st August 1966, Whitman murdered his wife and his mother and then climbed a tower on the campus of the University of Texas where he was studying, and shot 45 people, killing 13. During the ensuing shoot-out with law enforcement, he was shot and killed by a police officer. Later, notes written by Charles were discovered around his house, including one which read; "It was after much thought that I decided to kill my wife, Kathy…I love her dearly…I cannot rationally pinpoint any specific reason for doing this". A post-mortem of Whitman’s brain found a tumour the size of a walnut pressing on his amygdala. The conclusion was drawn that perhaps this was the cause of his sudden extreme violence, since the amygdala has been linked to aggression and emotion regulation. But if this is the case, where does the responsibility lie?

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