Biological explanations of crime

• Brain injury: damage to the prefrontal cortex can impair impulse control, planning and moral reasoning. The classic illustration is Phineas Gage; Raine et al. (1997) found reduced prefrontal glucose metabolism in murderers pleading NGRI. But brain differences may be a consequence of a violent lifestyle, and most people with such damage do not offend.
• Amygdala and aggression: the amygdala processes threat and emotion; abnormal amygdala functioning is associated with poor fear conditioning and reduced empathy, which may reduce the inhibition of antisocial behaviour.
• XYY syndrome: the claim that an extra Y chromosome predisposes men to violence. XYY men are somewhat over-represented in secure institutions, but the great majority of XYY men are not violent offenders, the numbers are tiny, and they may be over-represented for other reasons (e.g. height, lower IQ influencing detection).
• Personality: Eysenck argued criminals score highly on extraversion, neuroticism and psychoticism — extraverts need more stimulation and condition poorly, so they do not learn society's rules easily.

Watch the debate: biological explanations are determinist and reductionist, and they are socially sensitive — claiming crime is 'in the genes' has real consequences for responsibility, sentencing and stigma.

Labelling and the self-fulfilling prophecy

• Labelling: society labels an act, and the person, as 'deviant'. The label becomes a master status — everything the person does is reinterpreted through it (compare Rosenhan's sticky psychiatric label).
• Self-fulfilling prophecy: the labelled person is treated as a criminal, opportunities close, they internalise the identity, and they come to behave in line with the label — so the prophecy makes itself true.
• Social learning also matters: offending can be modelled and vicariously reinforced within a peer group or family.

Individual differences: not everyone who is labelled goes on to offend — personality, self-esteem and support all moderate whether a self-fulfilling prophecy takes hold. That is exactly the interactionist point Edexcel wants you to make.

Which explanation?

Factors affecting eyewitness testimony

Memory is reconstructive (Bartlett), so testimony can be distorted.

• Post-event information — misleading information encountered after the event (leading questions, other witnesses, media coverage) becomes incorporated into the memory.
• Weapon focus — when a weapon is present, attention narrows onto it, and recall of the perpetrator's face is poorer. Anxiety may enhance memory for central details while impairing peripheral ones.
• Anxiety: Valentine and Mesout (2009) — a contemporary study option — measured state anxiety in visitors to the London Dungeon and found that those with higher state anxiety recalled fewer correct descriptors of the actor and were less likely to identify him correctly from a line-up.
• But: Yuille and Cutshall (1986) interviewed real witnesses to a shooting in Vancouver months later and found recall remained highly accurate, and misleading questions had little effect — suggesting lab studies may underestimate real-world eyewitness accuracy.

What kind of explanation or factor?

Tap a card, then tap where it belongs.

Classic study: Loftus and Palmer (1974)

Experiment 1: 45 students watched films of car crashes and were asked "About how fast were the cars going when they ___ each other?" with a different verb for each group.

• Mean speed estimates (mph): smashed 40.8 · collided 39.3 · bumped 38.1 · hit 34.0 · contacted 31.8. A single word changed the estimate by around 9 mph.
• Experiment 2: 150 participants saw a crash and were asked about speed using smashed, hit, or were asked no speed question (control). A week later they were asked: "Did you see any broken glass?" There was none in the film.
• Findings: 32% of the smashed group reported broken glass, compared with 14% of the hit group and 12% of the control group.

Conclusion: the leading question did not just bias the response — it altered the stored representation of the event, supporting reconstructive memory. Evaluate it: excellent control and a devastating real-world application, but films are not real crashes (low ecological validity, no real emotional arousal), and the student sample lacked experience of judging speeds.

Loftus and Palmer

The cognitive interview and ethical interviewing

The cognitive interview (Fisher and Geiselman) applies memory research to police interviewing. Its four components are:

• Report everything — include every detail, however trivial; small details may cue others.
• Context reinstatement — mentally return to the scene (weather, feelings, layout) to provide retrieval cues.
• Change the order — recall the event in reverse; this disrupts the influence of schemas and expectation.
• Change the perspective — describe it from another person's viewpoint, to reduce schema-driven reconstruction.

Evaluation: the CI generally increases the number of correct details recalled, but it can also increase incorrect details, and it takes more time and training than a standard interview. An ethical interview avoids leading, coercive or oppressive questioning — crucial given how easily post-event information contaminates memory.

Which CI component?

Two treatments for offenders

You need one cognitive-behavioural and one biological treatment, each with a study of its effectiveness.

• Anger management (cognitive-behavioural): three stages — cognitive preparation (identify triggers and the thoughts behind the anger), skills acquisition (relaxation, assertiveness, self-talk) and application practice (role-play in a controlled setting). Howells et al. (2005) — a contemporary study option — evaluated brief anger management programmes with offenders and found only modest overall gains, with outcomes better for those who entered the programme highly motivated.
• Biological treatment — dietary supplementation: Gesch et al. (2002) gave young adult prisoners either vitamin, mineral and fatty-acid supplements or a placebo in a double-blind randomised trial; those receiving supplements committed significantly fewer disciplinary offences than those on placebo. It is cheap and requires no effort, but it treats a physiological correlate rather than the causes of offending, and long-term effects are unclear.

Evaluating treatments: effectiveness (does reoffending fall?), appropriateness (does it match the cause?), cost, drop-out and motivation, and social control — including the power of the person delivering the treatment.

Match the term to its meaning

Tap a term on the left, then its correct definition on the right.

Jury decision-making

Verdicts should depend only on the evidence — but they are influenced by:

• Characteristics of the defendant — attractiveness, accent, race and social status can shift judgements of guilt, even though they are legally irrelevant. Bradbury and Williams (2013) — a contemporary study option — examined how the racial composition of juries relates to decision-making.
• Pre-trial publicity — media coverage acts as post-event information, contaminating what jurors believe they know; instructions to disregard it are often ineffective.
• Group processes — majority influence and conformity operate inside the jury room, so a confident majority can pull dissenters along.

Methodological caution: most jury research uses mock juries of students who know their verdict has no consequences — a serious threat to ecological validity. Real jury deliberations cannot legally be studied in the UK.

Jury bias

Researching crime

• Laboratory experiments (Loftus and Palmer) give control and causal inference but low realism; field experiments (staged events in a real setting) raise realism but lose control and raise consent problems.
• Case studies of individual offenders give depth, but no generalisability.
• Sampling: random, stratified, volunteer, opportunity — offender samples are usually opportunity samples of caught offenders, which biases conclusions towards those who were unsuccessful enough to be convicted.
• Analysis: central tendency, frequency tables, range and standard deviation, correlation and meta-analysis; inferential tests — chi-squared, Spearman's rho, Mann-Whitney U, Wilcoxon; and thematic analysis or grounded theory for qualitative data.
• Ethics: the BPS Code (2009) and HCPC principles, plus risk management when working with offenders.

Sampling bias

Issues and debates

How Topic 6 is assessed

Criminological psychology is one of three options and, if you take it, is assessed in Section B of Paper 2. Clinical psychology (Section A) is compulsory alongside it.

• Expect application to a novel scenario — a witness statement, an offender's history, a jury.
• Know Loftus and Palmer (1974) in numerical detail, and be able to set it against Yuille and Cutshall (1986) to argue about ecological validity.
• Two treatments with a study of effectiveness for each — this is explicitly required, so name Howells et al. (2005) or Gesch et al. (2002).

Do not confuse the options. If you have studied criminological psychology, you answer only the criminological questions in Section B — you do not need child or health psychology at all.

The big ideas to know

That is Topic 6 — remember it is one of three options for Section B of Paper 2. Press Finish to see your score.