Biological and Psychological Explanations of Offending

Forensic psychology asks a hard question: why do some people commit crime? AQA groups the answers into two families, and a strong exam answer needs to keep them apart.

Biological explanations locate the cause inside the person — in their genes and their brain. On this view, offenders differ physically from non-offenders, and those differences are largely inherited.

Psychological explanations locate the cause in personality, thinking and learning. Here, offending comes from a particular personality type, faulty thought patterns, immature moral reasoning, or attitudes picked up from other people.

Family	Core claim	Named explanations on the spec
Biological	Offending is inherited and rooted in the brain	Genetic (twin/adoption studies, genes); neural (brain differences)
Psychological	Offending comes from mind, personality, learning	Eysenck's criminal personality; cognitive; differential association

The exam rewards precision. Name the specific explanation (for example "differential association theory"), the psychologist behind it, and the evidence — not just "biology" or "upbringing".

The genetic explanation argues offending is partly inherited. Crime clusters in families, and two research designs try to separate genes from shared upbringing.

Twin studies compare concordance rates — how often both twins share a trait. Identical (MZ) twins share 100% of their genes; non-identical (DZ) twins share about 50%. If genes matter, MZ concordance should be higher.

Christiansen studied over 3,500 twin pairs in Denmark and found higher concordance for criminal behaviour in MZ twins than in DZ twins, consistent with a heritable component.

Adoption studies separate biological inheritance from the rearing environment, because the child is raised by people they are not related to.

Mednick et al. (1984) studied over 14,000 Danish adoptees and found their likelihood of a criminal conviction was linked more closely to their biological parents than to their adoptive parents — pointing to inherited risk.

Researchers also point to candidate genes. A large study identified two associated with offending:

Gene	Associated role
MAOA	Regulates the neurotransmitter serotonin; low activity linked to aggression
CDH13	Involved in neural connectivity; linked to impulse control and ADHD

Crucially, concordance is well below 100%, so genes are a predisposition, not a guarantee.

The neural explanation argues offenders show differences in brain structure and activity, particularly in regions that control impulses and emotion.

The headline evidence is Raine et al. (1997), who used PET scans on murderers who had pleaded not guilty by reason of insanity (NGRI):

Raine found reduced activity in the prefrontal cortex of these offenders compared with controls. The prefrontal cortex normally regulates impulse control and emotional behaviour, so reduced activity may make impulsive, antisocial acts more likely.

Other neural findings include:

• Limbic system and amygdala abnormalities, which affect how threat and emotion are processed.
• Antisocial personality disorder (APD), characterised by a lack of empathy, has been linked to reduced grey matter in the prefrontal cortex.

Brain region	Normal function	Link to offending
Prefrontal cortex	Impulse control, emotional regulation	Reduced activity in violent offenders (Raine)
Amygdala / limbic	Processing emotion and threat	Abnormal activity linked to aggression

The prefrontal cortex is the brain's brake pedal on impulsive behaviour; if it under-functions, the brake is weaker. Note, though, that these are differences in activity — the causal direction is not settled.

Eysenck bridged biology and psychology: he argued personality has biological roots in the nervous system, and that a particular personality type is prone to offending.

He measured personality on three dimensions using the Eysenck Personality Questionnaire (EPQ):

Dimension	High scorer is...	Why it links to offending
Extraversion (E)	Outgoing, stimulation-seeking	Under-aroused nervous system; seeks risky stimulation
Neuroticism (N)	Anxious, unstable, over-reactive	Over-reacts to situations, making behaviour hard to predict
Psychoticism (P)	Cold, aggressive, lacking empathy	Traits directly associated with antisocial behaviour

Eysenck argued the typical offender scores high on extraversion, neuroticism AND psychoticism — not on one dimension alone.

The second half of the theory is about conditioning. Eysenck claimed people normally learn to behave morally through socialisation: as children, punishment conditions us to feel anxiety about wrongdoing, so we avoid it. He proposed that people with a criminal personality have a nervous system that conditions poorly — they do not build these anxiety responses easily, so socialisation fails to teach them to avoid antisocial behaviour.

So for Eysenck, biology (the nervous system) sets up a personality that learning then fails to correct.

Cognitive explanations focus on how offenders think — both how they reason about right and wrong, and how they interpret the world.

Level of moral reasoning builds on Kohlberg's stages of moral development, which run from a self-interested pre-conventional level up to a principled post-conventional level.

Offenders are more likely to reason at the pre-conventional level — obeying rules only to avoid punishment or to gain reward — rather than at higher levels based on maintaining social relationships or abstract principles.

Cognitive distortions are faulty, biased ways of interpreting events. The spec names two:

Hostile attribution bias

Misreading ambiguous or neutral cues as hostile or threatening. An offender might interpret a stranger's glance as a challenge or provocation, and respond aggressively to something that was never a threat.

Minimalisation

Downplaying the seriousness or consequences of an offence to reduce guilt. A burglar might describe theft as "just supporting my family", or a sex offender might deny the harm caused. The behaviour is reframed as less serious than it is.

Distortion	Timing	What is misjudged
Hostile attribution bias	Before/during acting	Others' intentions (read as hostile)
Minimalisation	After the offence	The seriousness of one's own actions

These distortions describe the thinking patterns that accompany offending and are directly targeted by CBT-based interventions.

Sutherland's differential association theory rejects biology and personality altogether. It argues offending is entirely learned — through interaction with other people, especially in intimate personal groups such as family and peers.

Two things are learned:

1. Attitudes and values — whether crime is seen as acceptable or unacceptable.
2. Techniques — the practical skills for committing specific offences.

The key mechanism is a kind of tally:

If the pro-crime attitudes a person is exposed to outweigh the anti-crime attitudes, they are more likely to offend. It is the balance of influences in a person's social environment that predicts offending, not their genes or personality.

This makes crime a normal product of socialisation: a person surrounded by attitudes favourable to law-breaking learns to offend in the same way anyone learns the norms of their group. It also explains why crime can recur in the same families or neighbourhoods — the pro-crime attitudes are passed on socially — and why prison, by surrounding inmates with other offenders, might actually increase reoffending.

For Sutherland, the cause of crime is not in the person but in the social environment that shaped them.

A strong essay weighs these explanations against the evidence rather than just describing them.

Biological explanations have supporting evidence but real limits. Twin and adoption studies (Christiansen, Mednick) and Raine's brain scans give the biological account genuine empirical support. However, twin concordance is below 100%, so genes cannot be the whole story, and MZ twins typically share a more similar environment than DZ twins, confounding genes with upbringing. Neural findings are correlational — reduced prefrontal activity may accompany offending without causing it. Biological accounts also ignore how crime is socially defined: what counts as an offence varies across time and culture, which no gene can explain.

Eysenck's theory has mixed support. The EPQ links some offenders to high E, N and P, but evidence is inconsistent: Farrington et al. found offenders scored high on psychoticism but not reliably on extraversion and neuroticism. The idea of a single, stable criminal "type" is questioned, and there is evidence of cultural bias — Bartol and Holanchock found low-E offenders in a US sample, contradicting the theory.

Cognitive explanations may describe rather than cause offending. Distorted thinking and pre-conventional reasoning are found in offenders, but they may be a consequence or correlate of a criminal lifestyle as much as its cause. Their strength is practical application: they underpin anger management and CBT-based interventions that target hostile attribution bias and minimalisation, giving the approach real-world value.

Differential association shifted the focus to the environment. Moving the explanation away from individual pathology towards learning was a major strength, and the theory can account for crime across different social groups and offence types. But "the number of pro-crime attitudes" is very hard to measure or test, weakening its scientific credibility, and it struggles to explain why many people heavily exposed to pro-crime influences never offend.

1. Confusing hostile attribution bias with minimalisation

Hostile attribution bias is misreading neutral or ambiguous cues as hostile or threatening. Minimalisation is downplaying the seriousness of an offence after it has happened. They are different distortions at different stages — do not use them interchangeably.

2. Saying Eysenck's offender is high on only one dimension

The criminal personality scores high on all three dimensions — extraversion, neuroticism and psychoticism — not just one. Dropping a dimension, or forgetting the poor-conditioning explanation, loses marks.

3. Treating twin concordance as proof of a "crime gene"

Concordance rates are well below 100%, and MZ twins share environments as well as genes. The genetic explanation supports a predisposition, not a single deterministic gene. Writing that there is a "gene for crime" overstates the evidence.

4. Forgetting differential association is about learned attitudes

Differential association is not just about mixing with criminals. It is about the balance of pro-crime versus anti-crime attitudes and techniques a person learns. Reducing it to "spending time with criminals makes you a criminal" misses the mechanism.

5. Not evaluating the direction of causation

For neural and cognitive explanations, remember the findings are largely correlational. Brain differences and distorted thinking may be a result of offending or a shared third factor, not necessarily its cause. Naming this earns AO3 credit.