Biological explanations of crime and anti-social behaviour

Genetic Factors

Twin studies may indicate a genetic influence on criminal behaviour, as there is higher concordance for criminal behaviour between identical twins as compared to non-identical twins.
Adoption studies show that there’s a strong correlation between criminal behaviour in biological parents and adopted children, suggesting hereditary factors might play a role.
Candidate genes: Some specific genes have been linked with aggressive behaviour, such as the MAOA gene.

The prefrontal cortex is responsible for impulse control, decision making and social behaviour. Damage or impairment in this area can lead to increased likelihood of criminal behaviour.
Neurochemicals, such as serotonin and dopamine, are implicated in aggressive behaviour. Low levels of serotonin and high levels of dopamine are typically associated with increased aggression and impulsivity.
Autonomic Nervous System (ANS) arousal: Lower resting heart rate and skin conductance are often associated with higher levels of antisocial behaviour, indicating lower baseline arousal levels in the ANS of criminals.

Testosterone is often linked with aggression and thus potentially crime, especially in males.
Cortisol, the stress hormone, when low, can be linked to antisocial behaviour. Low cortisol levels may indicate a lack of fear or apprehension towards potential consequences.

These fields of study imply some level of biological determinism, the theory that biological factors alone can fully account for crime. This perspective doesn’t fully take into account environmental factors that have been shown to play a crucial role in the development of antisocial or criminal behaviour.

Diathesis-stress model suggests that biological vulnerabilities (diathesis) can lead to criminal behaviour, but only when triggered by situations or events in a person’s environment (stress). This model emphasises the interplay of both nature and nurture.
Neuroplasticity: Recent research suggests that brain structures and neurochemical balances can be altered by environmental factors, illustrating how nature and nurture constantly interact to shape our behaviour, potentially leading to criminal or antisocial outcomes.