Biological Explanations of Offending Behaviour (AQA A-Level Psychology): Revision Notes
Neural Explanation
Neural explanation of offending behaviour refers to a biological theory suggesting that abnormally functioning brain physiology and biochemistry form the basis of an individual's criminal behaviour.
Neural explanations for offending behaviour focus on two main areas: the biochemistry of neurotransmitters and the physiology of brain structures and development.
Biochemistry
Three key biochemicals play important roles in offending behaviour: noradrenaline, serotonin and dopamine.
Noradrenaline
Noradrenaline forms part of the fight-or-flight response system, helping individuals react to threatening situations. Research indicates that elevated levels connect to violence and aggression. This makes it relatively straightforward to explain certain crimes as resulting from chemical imbalances in the brain.
The fight-or-flight response is an evolutionary survival mechanism that prepares the body for immediate action when faced with threats. When this system becomes overactive due to elevated noradrenaline, it may contribute to aggressive responses in situations that don't actually warrant such intense reactions.
Serotonin
Serotonin controls mood and impulse regulation. When levels are low, this becomes associated with criminal behaviour due to increased impulsivity. During particularly emotional situations, individuals with low serotonin levels may react impulsively because they lack the capacity to restrain themselves effectively.
Dopamine
Dopamine links to offending behaviour through its connection to addiction and substance abuse, which increases crime likelihood. Dopaminergic activity occurs in the limbic system, where pleasure is experienced - the higher the activity, the greater the pleasure sensation. This pattern makes addiction more probable, creating a cycle that can lead to criminal behaviour.
Research evidence
Higley et al. (1996) discovered that testosterone levels showed positive correlation with aggressiveness but not impulsivity. In contrast, serotonin levels correlated negatively with impulsive behaviour and extreme aggression (though not general aggression). These findings suggest biochemical levels may influence offender behaviour.
Krakowski (2003) reported that whilst serotonin linked to lack of impulse control and violence, establishing causal relationships proved difficult. Individual differences and social context also influence behaviour. For instance, violent events in crowded situations might prompt different reactions compared to solitary settings, even with identical serotonin levels.
Research Example: The MAOA Gene Study
Brunner (1993) examined effects of the MAOA gene, which affects neurotransmitter levels in individuals with the shortened gene version.
Key Finding: This gene connects to aggressive behaviour and can apply to violent crime patterns.
Significance: This study provided early evidence for genetic influences on neurotransmitter function and subsequent behavioural outcomes.
Brain physiology
Brain physiology research examines how the limbic system and brain development patterns might contribute to offending behaviour.
Limbic system
The limbic system represents a central brain region considered the primitive area responsible for emotion regulation. This positioning makes it potentially relevant to offending behaviour.
Criminal psychopaths (those with anti-social personality disorder) demonstrate particular patterns here. Psychopathy is a personality disorder without clear cause, where individuals appear to struggle with processing emotions and empathy. This creates a lack of remorse or guilt when their actions harm others negatively. Research suggests that limbic system faults may lead to reduced emotional reactions, potentially resulting in planned and organised offending behaviour since psychopaths lack remorse and prioritise self-interest.
Brain development
Research examining brain development's role in offending behaviour centres on individuals with anti-social personality disorder.
Raine et al. (2000) found that frontal lobe volume in people with anti-social personality disorder was smaller than in those without the condition. This reduced activity may explain why individuals with anti-social personality disorder don't experience guilt or demonstrate conscience. Without this internal 'brake' system that prevents most people from committing crimes against others, offending becomes more likely.
The frontal lobe, particularly the prefrontal cortex, is crucial for executive functions including impulse control, moral reasoning, and consequence evaluation. When this area is underdeveloped or damaged, individuals may struggle with the cognitive processes that typically prevent antisocial behaviour.
Research evidence
Kent et al. (2001) used fMRI scanning to identify brain activity abnormalities during emotion-based tasks. Their brain scans revealed that criminal psychopaths showed much less limbic system activity than non-criminal control participants during emotional tasks, with psychopaths relying more heavily on their frontal lobe. This supports the connection between brain physiology and criminal behaviour.
Raine et al. (1997) investigated brain activity differences between murderers and non-murderers. They studied 41 violent murderers who pleaded not guilty by reason of insanity, requiring assessment using PET scanners. Raine's team identified brain activity differences in regions linked to aggression, such as the prefrontal cortex and limbic system areas, again supporting brain physiology's relationship to criminality.
Fallon (2013) conducted brain scans on psychopaths, discovering unusually low activity patterns in frontal lobe sections associated with empathy and control. This research provides additional evidence that brain development and abnormalities contribute to criminal behaviour.
Evaluation
Limitations
Critical Limitation: Indirect Relationships
Biochemical explanations may relate more to everyday behaviour patterns, which subsequently lead to offending in certain circumstances. Biochemistry might also underpin mental illness, increasing crime likelihood in some situations rather than directly causing criminal acts. This suggests the relationship operates indirectly rather than through direct causation.
Much neurotransmitter research uses animal subjects, creating validity concerns. Observing increased aggression in mice with elevated neurotransmitter levels doesn't automatically translate to humans committing violent crimes.
Biochemical explanations are reductionist, oversimplifying criminal behaviour. Criminal activity likely involves far greater complexity than individual biochemical levels in someone's brain.
Brain physiology limitations
Clear connections between abnormal brain processing and crime may not be evident. Brain functioning problems could result from trauma - not everyone with head injuries commits crimes, even when damage compares to the changed physiology seen in research. Cause and effect relationships remain unclear since brain physiology issues don't affect everyone identically.
Nature vs. Nurture Consideration
Brain functioning issues may stem from childhood abuse, particularly physical violence. This raises questions about whether offenders bear full responsibility or whether circumstances beyond their control contributed to their behaviour.
Sample sizes for brain research tend to be small for two reasons: target populations (psychopaths and criminals) prove difficult to access, and scanning procedures are time-consuming and expensive. This affects how widely results can be generalised.
Key Points to Remember:
- Neural explanations focus on biochemistry and brain physiology - three key neurotransmitters (noradrenaline, serotonin, dopamine) and brain structures (limbic system, frontal lobe) influence criminal behaviour
- Research evidence supports biochemical links - studies show correlations between neurotransmitter levels and aggression/impulsivity patterns
- Brain structure differences exist in criminals - psychopaths show reduced activity in limbic system and frontal lobe areas controlling emotion and impulse control
- Causation remains unclear - brain differences may result from trauma or abuse rather than directly causing criminal behaviour
- Reductionist approach - criminal behaviour likely involves more complexity than individual biochemical or brain structure variations alone