Forensic Psychology

Problems in Defining Crime

Crime is typically defined as any action which breaks a law and results in a punishment, for example imprisonment. The problem with defining crime in this way is that laws can change from time to time and place to place, and not all acts that break the law are punished.

Cultural issues: Actions considered a crime in one culture are sometimes not classed as a crime in another culture. For example, the practice of having more than one wife is a crime in the UK (bigamy), but in some cultures, this would not be seen as a crime (polygamy).

Historical issues: Definitions of crime change over time, for example homosexuality was a crime until 1967 in the UK, and remains a crime in many Asian and African countries.

Forensic Psychology, figure 1

Ways of Measuring Crime

Official statistics: These are government records of numbers of crimes reported to the police and recorded in official figures. They are published annually by the Home Office. They are used by the government as information which can help to develop crime prevention strategies, for example.


  • Official statistics may underestimate the extent of crime. They only include reported crimes, which may be only around 25% of the total crimes committed (the remaining 75% is known as the ‘dark figure’). Of these, they only include recorded crimes. Some police forces may not record every crime they deal with, for example if it is a minor crime. Therefore, the validity of official statistics is lessened.

Victim surveys: These ask victims about their experience of crime. For example, in the UK 50,000 randomly selected households take part in the ‘Crime Survey for England and Wales’ each year. The Office for National Statistics uses the results of the survey to detect trends and patterns.


  • They can be more accurate than official statistics, as they include crimes not reported to the police. Therefore, the information gained may be more trustworthy.
  • They rely on memory and self-report, which can be unreliable. Participants may not remember when the crime took place- it may be longer than one year ago, for instance. This can lead to misleading information.

Offender surveys: These record examples of crimes through asking offenders to give details about crimes they have committed. Groups of likely offenders are often used, based on risk factors such as background, past offences and so on. An example was the ‘Offender Crime and Justice Survey’ (2003-2006).


  • Insight is provided into how many people are involved in the committing of a crime.
  • Participants may not be honest (even though confidentiality is assured)- they may under-report criminal actions, or over-report them for reasons of bravado. Therefore, the data may not be accurate.
  • Certain types of crime (middle-class, such as fraud) may be unrepresented, due to the type of offenders targeted for the surveys.

The Top-Down Approach

Offender profiling aims to creating a list of likely suspects for a crime, by narrowing down the possible field of perpetrators. This is done by professional profilers and the police, who use evidence and the crime scene to generate hypotheses about the characteristics of the killer, such as their age, occupation, and so on.

Forensic Psychology, figure 1

The top-down approach: This originated in the US (particularly, the FBI) in the 1970s. The characteristics of the crime, and the likely offender, is matched to a pre-existing ‘template’, provided by the FBI. For instance, a murder could be classified as ‘organised’ or ‘disorganised’. This is then used to guide police investigations. The templates suggest that the criminal has a particular way of working (‘modus operandi’ or ‘MO’), which correlates with an aspect of their personality, occupation, or something else about them. Templates were created through in-depth interviews with serial killers such as Ted Bundy and Charles Manson.

Organised and disorganised types: Organised offenders show evidence of advanced planning, and will ‘choose’ particular victims. They work in an emotionally detached way, leave little evidence, and tend to be intelligent, in skilled professional occupations. They are also able to display normal social and sexual behaviour. Disorganised offenders tend to be the opposite, in the sense that the crime (such as a murder) is not pre-planned, but is done on the spur of the moment, perhaps in response to a particular emotional trigger. The body will often therefore not be disposed of, because no plans have been made to do so, and more evidence is left behind. Such offenders tend to have lower IQs, be in unskilled work (or unemployed), and have histories of psychological and/or sexual dysfunction, in addition to living alone.

Constructing an FBI profile: There are four stages to the process:

  • Data assimilation: reviewing the available evidence
  • Crime scene classification: organised or disorganised
  • Crime reconstruction: a hypothesis of what happened
  • Profile generation: a hypothesis of the characteristics of the likely offender- background, personality traits, occupation, and so on


  • Top-down approaches work best for particular types of crime, such as premediated murder, rape, torture and so on. They work much less well for crimes such as burglary, because the crime scene reveals little about the offender. Therefore, the top-down approach can only be properly used for certain crimes.
  • The top-down approach relies on the prediction that personality characteristics remain fairly stable over time, sometimes over years or decades. Therefore, it does not consider that personality may be strongly affected by external factors, reducing the validity of this approach.
  • The top-down approach may be too simplistic in its categories. For instance, it would be hard for it to explain a spontaneous killing carried out by an educated, professional person. It has been suggested that there may by overlap between the ‘organised’ and ‘disorganised’ categories, reducing the validity of the approach.

The Bottom-Up Approach

The bottom-up approach: This was developed in the UK by David Canter (amongst others). The aim is to generate a profile of the offender by looking at the available evidence. There are no fixed ‘typologies’ (as in the US system) that will be attempted to be matched to the offender. Instead, a profile should emerge solely from the evidence of each case.

Investigative psychology: This is an attempt to use statistical procedures and psychological theory. Statistics are used to create a prediction of behaviour that is likely to occur in crimes. Specific details of an offence are matched to this to create details about the offender. The idea of ‘interpersonal coherence’ is key- how the offender acts during the crime is likely to relate to their actions in non-criminal situations. For example, a murderer who leaves a very neat and tidy crime scene may be obsessively neat and tidy in everyday life. The significance of the time and place of the crime is also considered, as is ‘forensic awareness’, where it is considered how much the offender has attempted to cover their tracks- this indicates they may have been questioned about crimes before.

Geographical profiling: Rossmo (1997) proposed this method, which involves looking at the location of crimes which seem to have been committed by the same offender (‘crime mapping’). Hypotheses can be generated about what the offender is thinking, how they like to operate, where they live or are basing themselves (‘centre of gravity’), and where they are next likely to commit a crime (known as the ‘jeopardy surface’). Canter’s ‘circle theory’ proposed two models. The marauder operates in close proximity to their home, or an equivalent ‘base’. The commuter travels a distance away from their residence. Patterns of offending usually form circles around an offender’s residence, and this can give insights into whether offences were planned, modes of transport involved, the age of the offender, and so on.

Forensic Psychology, figure 1


  • Canter and Heritage (1990) found that when looking at a particular type of crime (sexual assault), the nature of the offence was correlated with particular types of behaviour (such as the use of impersonal language). This suggests that statistical techniques can be useful in identifying behaviour patterns, so supporting investigative psychology.
  • Lundrigan and Cantor (2001) found that, in 120 murder cases involving serial killers, the killer disposed of bodies in various locations, which formed ‘centres of gravity’, and their base or residence was always located in the middle of this. This supports the use of geographical profiling in helping determine a killer’s base.
  • Bottom-up approaches could be argued to be more scientific than top-down, as just the available evidence (alongside statistical analysis and predictions) are used to create a profile, rather than attempting to fit offenders to pre-exiting templates. Therefore, this may be a more valid approach to offender profiling.

Atavistic Form

Biological explanations of criminal behaviour assume that it is caused by innate tendencies, possibly determined by genes. Brain structure or functioning may be the cause of crime. One such approach, known as the historical approach, was developed by Lombroso (1876).

Atavistic form: Lombroso argued that criminals were genetic throwbacks, meaning that they were more primitive than non-offenders, and were unsuited to living in civilised society. They would therefore best be seen as a ‘sub-species’ of humanity. These ideas helped to move explanations for criminal behaviour towards a more scientific realm, but seem speculative by modern standards.

Atavistic characteristics: As criminal behaviour is biologically determined, Lombroso suggested that there were also physical characteristics accompanying the ‘sub-species’. These characteristics could be used to identify criminals just by looking at their face and head. They include:

  • Narrow, sloping brow
  • Prominent jaw
  • High cheekbones
  • Facial asymmetry
  • Dark skin
  • Physical irregularities such as extra toes/fingers

Lombroso even suggested that particular types of criminals had particular features. For instance, a murderer would have bloodshot eyes, curly hair and long ears. Fraudsters would have thin lips. Criminals generally would, according to Lombroso, be insensitive to pain, use criminal slang language, have tattoos, and be unemployed.

Lombroso studied the heads and faces of hundreds of convicts in his native Italy, concluding that (of 383 dead and 3839 living criminals studied), 40% of all criminal acts could be accounted for by atavistic characteristics.


  • Lombardo’s theories were the first attempt to explain criminal behaviours in a more scientific (rather than moralistic) way, by considering physiology and genetics. This helped pave the way for further investigation into evolutionary and biological explanations.
  • Lombroso’s work has been accused of racism, as many of the atavistic features (dark skin, curly hair) are also features of people of African descent. The danger in accepting these theories would be that they could be used to support selective breeding (eugenics) in humans, which would be ethically unjustifiable today.
  • Goring (1913) found that, when comparing 3000 criminals with 3000 non-criminals, there was no evidence of particular physical characteristics amongst criminals, weakening the suggestion that it is possible to identify potential offenders just by sight.

Genetic Explanations

Genes consist of strands of DNA, which instruct the body how to grow and develop, as well as determining neuroanatomy (brain structure) and biochemistry (levels of neurotransmitter activity in the brain). Genetic explanations suggest that particular genes, or combinations of them, are associated with criminal behaviour. Lange (1930) looked at 13 identical (MZ) and 17 non-identical (DZ) twins, where one twin in each pair had served time in prison. 10 of the MZ twins, and only 2 of the DZ twins, had a co-twin also in prison, suggesting a genetic basis for criminal behaviour. Christiansen (1977) found concordance rates of 33% for MZ and 12% for DZ twins for criminal behaviour, also showing a possible genetic link.

Candidate genes: Tiihonen et al (2014) found that the MAOA gene (which is linked to dopamine and serotonin and aggressive behaviour) and the CDH13 gene (linked to attention deficit disorder) may be associated with violent crime, although the findings have yet to be replicated.

Diathesis-stress: The tendency for criminal behaviour may be established genetically, but it is likely that an environmental ‘trigger’, such as a traumatic or dysfunctional childhood, is needed to cause the criminal behaviour. This is known as the diathesis-stress model.

Neural Explanations

Forensic Psychology, figure 1

These consider how the structure and workings of the brain may be linked with criminal behaviour. Individuals diagnosed with antisocial personality disorder (APD) may have a neural explanation for their condition. APD is characterised by lack of empathy and reduced emotional responses.

Prefrontal cortex: Raine has found through conducting brain imaging studies that individuals with antisocial personalities have reduced activity in the brain’s prefrontal cortex. In a 2000 study, it was found that individuals with APD had 11% less brain matter in the prefrontal cortex than a control group. The role of the prefrontal cortex includes regulation of emotional behaviour, therefore dysfunction in this area may lead to dysfunction in emotional response.

Mirror neurons: Keysers et al (2011) found that when criminals were asked to empathise with someone on film experiencing pain, the empathy reaction (controlled by mirror neurons) activated. This suggests that those with APD are capable of empathy, but it is a process that can be switched on and off, unlike in a ‘normal’ brain.


  • Twin studies often use very small sample sizes, and early examples such as Lange’s may not have been well-controlled, therefore reducing the validity of findings. This is made more problematic by the fact that twins share environments, so any similarity could be due to this rather than genetics.
  • Mednick et al (1984) found that, of 13,000 Danish adoptees, 13.5% of those who did not have a biological parent with a criminal conviction had convictions themselves. Of those who had one biological parent with a criminal conviction, 20% had a conviction themselves. Of those who had two parents with a criminal conviction, 24.5% had a conviction themselves. This supports that there may be a genetic basis for criminal behaviour, which is moderated by the environment (supporting diathesis-stress).
  • Biological explanations are determinist, suggesting that criminals do not have free will over their behaviour. This has implications for criminal responsibility, as a genetic factor could be used as a defence in cases of crime. This raises ethical questions as to how far responsibility should be given to offenders, and therefore if/how they should be punished. The biological explanation could be argued to be overly deterministic in its explanation.
Discuss genetic and/or neural explanations of offending behaviour. (16 marks - 6 outline - around 3 paragraphs; 10 evaluate - around 3-4 evaluation points)
Your answer should include: Twin / Studies / MAOA / CDH13 / Diathesis-Stress / Prefrontal / Cortex / Personality / Disorder / Neurons / Validity / Mednick / Determinism