Forensic psychology

outline offender profiling

• A behavioural and analytical tool that is intended to help investigators accurately predict and profile the characteristics of unknown offenders.

• to generate hypotheses

outline top down approach

• Developed by the FBI’s Behavioural Science Unit using interviews with 36 sexually motivated murderers, including Ted Bundy and Charles Manson.

• Uses pre-defined criminal profiles based on past cases.

• Crime scene evidence is analysed to decide whether the offender fits an organised or disorganised category.

• Each category has specific behavioural characteristics.

• If a crime scene matches one category, investigators can predict likely traits of the offender.

characteristics of an organised offender

• crime is planned

• victim is deliberately targeted, offender has a type of victim they seek out

• high degree of control during the crime

• little or no evidence left at crime scene

• tend to be above average or high intelligence

• skilled, professional occupation

• socially and sexually competent

• may be married with children

characterises of a disorganised offender

• crime is impulsive with little or no planning

• lacking control

• evidence left behind

• below average or low intelligence

• unskilled work or unemployed

• socially and sexually incompetent

• lives alone

outline stages of constructing an FBI profile

1. data assimilation- the profiler reviews the evidence

2. crime scene classification- as either organised or disorganised.

3. crime reconstruction- hypotheses in terms of sequence of events, behaviour of the victim, etc

4. profile generation- hypotheses related to the likely offender

outline modus operandi

serious offenders have certain signature ‘ways of working’ and these generally correlate with a particular set of social and psychological characteristics that relate to the individual.

strength of top down approach

• Research support for the organised offender category.

• David Canter et al. (2004) analysed 100 US serial murders using smallest space analysis.

• Found a cluster of behaviours (e.g., restraint, body concealment) matching the FBI organised offender typology.

• Shows patterns of behaviour exist in serial crimes.

• Therefore: supports the validity and scientific credibility of the top-down approach.

strength for top down approach

• Wider application to other crimes.

• Tina Meketa (2017) applied top-down profiling to burglary in three US states.

• Added new categories: interpersonal (offender knows victim) and opportunistic (inexperienced offender).

• Led to an 85% increase in solved cases.

• Therefore: suggests top-down profiling has greater practical usefulness and applicability than originally thought

weakness of top down approach

• Based on weak and unrepresentative evidence.

• FBI typology developed from interviews with only 36 US murderers.

• Sample was small, non-random, and lacked different offender types.

• Interviews had no standardised questions, reducing reliability.

• David Canter argued the data is methodologically flawed.

• Therefore: top-down profiling may lack a strong scientific basis.

outline bottom up approach

Profilers work up from evidence collected from the crime scene to develop hypotheses about the likely characteristics, motivations and social background, investigation does not begin with fixed typologies

outline investigative psychology

• Uses statistical analysis + psychological theory to analyse crime scenes

• Identifies patterns of behaviour across offences

• Builds database (baseline) → compare new crimes

• Helps infer offender details (background, history) + link crimes

• Interpersonal coherence → behaviour with victim reflects everyday behaviour

outlie geographical profiling

• Uses crime locations to predict offender’s home/base

• Based on spatial consistency (crimes in familiar areas)

• Centre of gravity → base likely in middle of crime pattern

• Circle theory (Canter) → crimes form circle around home

• Marauder → crimes near home

• Commuter → travels away

• Gives clues about planning + offender traits

strength for investigative psychology

• David Canter & Rupert Heritage (1990) → 66 sexual assault cases

• Found behaviour patterns (data was examined using smallest space analysis)

• Supports consistency → case linkage

• ✔ Backed by research evidence

limitation for investigative psychology

• Circular data issue → database = solved crimes only

• Easier cases more likely included

• Less useful for unsolved/complex crimes

strength for geographical profiling

• study → 120 murder cases

• using smallest space analysis - Found spatial consistency + centre of gravity

• Strong support for marauder pattern

• ✔ Shows profiling can locate offender

limitation of geographical profiling

• Relies on accurate police data

• Many crimes not reported (dark figure of crime)

• Data can vary between areas → less reliable

• Ignores other factors (e.g. time, offender experience)

• ❗ Should be used with other methods, not alone

biological: outline the historical approach

• Cesare Lombroso (1876) → “criminal man” theory

• Claimed criminals are atavistic (genetic throwbacks)

• Said they are biologically different / primitive

outline biological approach

• criminals are atavistic (genetic throwbacks)

• Primitive/savage nature → can’t adapt to civilised society

• Crime is innate → rooted in genes

• Offenders not to blame → behaviour biologically determined

• ✔ Revolutionary idea at the time

outline atavistic form

• offender subtype could be identified as being in possession of particular physiological ‘markers’ that were linked to particular types of offence.

• these include biologically determined atavistic characteristics

what are the offender types Lombroso identified?

• using physical and facial features

• Murderers: bloodshot eyes, curly hair, long ears

• Sexual deviants: glinting eyes, swollen, fleshy lips, projecting ears

• Fraudsters: thin, reedy lips

outline Lombroso research for atavistic form

• Studied hundreds of Italian convicts, both living and dead

• Concluded there was an “atavistic form” – physical features indicating criminality

• Examined 383 dead and 3839 living convicts

• Suggested 40% of criminal acts are committed by people with atavistic traits

strength for lombroso

• Hailed as the “father of modern criminology”; coined the term criminology

• Shifted crime research from moralistic explanations (offenders seen as wicked/weak-minded) to a scientific approach (evolutionary and genetic influences)

• Linked types of people to types of crime, laying the groundwork for offender profiling

• Overall, made a major contribution to the science of criminology

limitation for lombroso

• Critics argue his legacy is not entirely positive

• Work contains racist undertones: traits like curly hair and dark skin linked to criminality

• Implicitly suggested that people of African descent were more likely to offend

• Reflects 19th-century eugenic attitudes

• Shows some of his theory was subjective and influenced by racial prejudice rather than objective science

limitation for lombroso

• Charles Goring (1913) compared 3,000 offenders with 3,000 non-offenders

• Found no evidence that offenders had unusual facial or cranial features

• Suggested some offenders have lower-than-average intelligence

• Challenges Lombroso’s idea that criminals are a distinct physical “subspecies

limitation for lombroso

• Lombroso’s methods were poorly controlled

• Did not use a non-offender control group, unlike Goring

• Failed to account for confounding variables (e.g., poverty, poor education)

• Limits ability to conclude that physical traits caused criminality

• Research does not meet modern scientific standards

outline twin studies for biological explanation

Twin studies: Karl Christiansen – 3,500 twin pairs in Denmark

• Concordance rates for male offenders: 35% identical (MZ) twins, 13% non-identical (DZ) twins

• Slightly lower rates for females

• Indicates both criminal behaviour and underlying traits may be inherited

limitation for twin studies

• Twin studies assume MZ and DZ twins share similar environments

• In reality, MZ twins (identical) are often treated more similarly than DZ twins

• This can affect behaviour, inflating concordance rates for MZ twins

• therefore higher concordance rates for MZs in twin studies may simply be because they are treated much more similarly than DZ twins.

outline adoption studies for biological explanation

• Adopted children with biological mothers who had criminal records: 50% risk of criminal record by 18

• Adopted children with non-criminal biological mothers: 5% risk

outline role of candidate genes for biological explanation

• Study: Tiihonen et al. (2015), ~800 Finnish offenders

• Genes identified:

  • MAOA: regulates serotonin; linked to aggressive behaviour

  • CDH13: linked to substance abuse and ADHD

• Found that 5–10% of severe violent crime in Finland is associated with these genotypes

outline diathesis stress model for biological explanation

• Genetics may influence offending, but effects are moderated by the environment

• Diathesis-stress model applied to crime: genetic predisposition + environmental triggers

• Environmental triggers could include: dysfunctional upbringing, criminal role models, or adverse experiences

strength for diathesis stress model for bio expl.

• study: 13,000 Danish adoptees → increases reliability and generalisability

  • Neither biological nor adoptive parents convicted → 13.5% adoptees convicted

  • Biological parent convicted → 20% adoptees convicted

  • Both biological and adoptive parents convicted → 24.5% adoptees convicted

• Shows both genetic inheritance and environmental influence affect offending

overview of neural explanation

• Evidence shows neural differences between offenders and non-offenders

• Many studies focus on Antisocial Personality Disorder (APD / psychopathy)

• APD associated with: reduced emotional responses, lack of empathy, common in convicted offenders

outline prefrontal cortex for neural explanations

• Prefrontal cortex: regulates emotional behaviour

• study: ~11% reduction in grey matter volume in APD brains compared to controls

• Dozens of brain-imaging studies show reduced activity in prefrontal cortex of APD individuals

outline mirror neurons for neural explanations

• Offenders with APD can feel empathy, but less consistently

• ]study: empathy activates only when explicitly prompted (via mirror neurons)

• Suggests APD individuals have a neural “switch” for empathy, unlike typical brains where empathy is automatic

strength of neural explanation

• researchers reviewed evidence linking frontal lobe damage to antisocial behaviour

• Found damage associated with impulsivity, emotional instability, and inability to learn from mistakes

• Frontal lobe controls planning and regulation of behaviour

• This supports the idea that brain damage may be a causal factor in offending behaviour.

limitation for neural explanation

• Link between neural differences and APD may be complex

• study: men high in psychopathy had risk factors in childhood (e.g., convicted parent, physical neglect)

• Early experiences may contribute to APD and neural differences (e.g., reduced frontal lobe activity)

• Suggests other intervening variables affect the relationship between brain differences, APD, and offending

outline Eysenck’s Personality Theory

• Behaviour can be described along two dimensions:

  • Extraversion – Introversion (E)

  • Neuroticism – Stability (N)

• Later added Psychoticism – Sociability (P)

• Different combinations produce different personality traits

outline biological basis of personality

• Personality traits are innate, biological, linked to the nervous system

• Extraverts: underactive nervous system → seek excitement, risk-taking, hard to condition so dont learn from mistakes

• Neurotics: highly reactive sympathetic nervous system → nervous, overanxious, unpredictable

• Psychotics: high testosterone → unemotional, aggressive

outline criminal personality and socialization

• Criminal personality = Neurotic + Extravert + Psychotic

  • Neurotic: unstable, overreacts

  • Extravert: seeks arousal, risky behaviour

  • Psychotic: aggressive, lacks empathy

• Socialisation: high E & N → difficult to condition → fail to learn anxiety responses to antisocial impulses → more likely to offend

outline measuring criminal personality

• Eysenck Personality Questionnaire (EPQ) measures E, N, P dimensions

• Links personality scores to criminality and other behaviours

strength for Eysenck theory

• Eysenck & Eysenck : compared 2070 prisoners with 2422 controls using EPQ

• Prisoners scored higher on extraversion, neuroticism, and psychoticism

• Supports idea that offenders have a distinct criminal personality

counterpoint to strength

• study: meta-analysis → offenders high in psychoticism only, not E or N

• study: inconsistent EEG evidence for cortical arousal differences

• This means some of the central assumptions of the criminal personality have been challenged

limitation to E’s theory

• study: distinguishes adolescence-limited vs life-course-persistent offenders

• Personality alone is a poor predictor of persistence in offending

• Suggests offending is due to interaction between personality and environment and complex than E’s theory

limitation to E’s theory

• Bartol & Holanchock (1979): studied Hispanic and African-American offenders in a maximum-security prison

• Offenders were divided into six groups based on offence type and history

• All groups were found to be less extravert than non-offender controls

• Contradicts Eysenck’s prediction that offenders should be more extravert

• Suggests findings may be influenced by cultural differences in the sample

• Implies the criminal personality may be culturally relative and not generalisable

outline moral development in level of moral reasoning

• Kohlberg: proposed a stage theory of moral reasoning based on moral dilemmas (e.g., Heinz dilemma)

• Higher stages = more sophisticated reasoning about right and wrong

• Offenders tend to show lower levels of moral reasoning than non-offenders

• a study by him: violent youths had lower moral development than non-violent youths (even when controlling for social background)

outline link between moral reasoning and criminal behavior

• Offenders more likely at pre-conventional level (stages 1–2)

• Behaviour driven by avoiding punishment and gaining rewards → more immature, egocentric thinking

• Crime more likely if there is reward or low risk of punishment

• Non-offenders more likely at higher levels → show empathy, honesty, and respect for others

• Supported by Chandler (1973): offenders are more egocentric and have poorer perspective-taking skills