Forensic Psychology

• Offender profiling

  • A method used by police to attempt to produce a probable profile of the criminal
  • Based on the idea that it is possible to work out the characteristics of an offender by examining the characteristics of their profile
  • Allows police to narrow down the field of suspects
• Approaches to offender profiling

  • Top-down - used by FBI in the USA
  • Bottom-up - used by police in the UK
• Top-down approach

  • Looking at the characteristics of crime scenes to assign offenders to different categories
  • Offenders have a signature way of working (modus operandi) which correlate with social and psychological characteristics
  • Evidence from the crime scene is used to fit the offender into organised or disorganised
  • A profile is then constructed, including a hypothesis about their background and character
  • This approach is seen as more intuitive
  • FBI drew upon data gathered from interviews with 36 sexually motivated serial killers
• Organised offenders

  • Planned the crime
  • Victim is deliberately targeted
  • Detached, surgical precision
  • Little evidence left behind
  • Above-average IQ
  • Skilled occupation
  • Married, may have children
• Disorganised offenders

  • Little evidence of planning
  • Usually impulsive
  • Crime scene reflects "spur of the moment"
  • Little control
  • Low IQ
  • Unskilled work or unemployed
  • Live alone, close to the scene
• Constructing an FBI profile

  1. Data assimilation - review the evidence
  2. Crime scene classification - organised or disorganised
  3. Crime reconstruction - sequence of events
  4. Profile generation
• Evaluating the top-down approach

  Weakness

  • Best suited to crimes that reveal important details about the suspect such as rape, arson and murder. More common offences don't lend themselves to profiling because the crime reveals little about the offender
  • This is a weakness because this means the top-down approach to identifying a criminal is limited because it only applies to specific types of crime
  • However, more recently, top-down profiling has been used for burglary cases resulting in an increase in solved cases. This suggests that the methods can be used more widely than once thought
• Evaluating the top-down approach

  Counter evidence

  • Canter et al. (2004) analysed data from 100 murders in the USA in terms of characteristics thought to be typical of organised and disorganised killers. Evidence was found of a distinct organised type but no disorganised type
  • Suggests that although there was evidence for an organised offender, the fact that there was none for a disorganised offender undermines the whole system
  • Nevertheless, this system is still used and has widespread support
• The bottom-up approach

  Profilers work up from evidence collected at the crime scene to develop hypotheses about the likely characteristics of the offender by making inferences from systematic analysis of evidence using knowledge of psychological theories and statistical analysis
• The bottom-up approach techniques

  • Investigative psychology
  • Geographical profiling
• Investigative psychology

  • Developed by Canter
  • Matches details from a crime with statistical analysis of typical offender behaviour patterns based on a psychological theory
  • Interpersonal coherence
  • Significance of time and place
  • Forensic awareness
  • Statistical procedures then applied - a database on patterns of behaviour
  • Specific details are matched against the database to reveal details about the offender
  • Hypotheses of probable characteristics are then created
• Interpersonal coherence

  The way an offender behaves at the scene can reflect everyday behaviour e.g. some rapists seek control while others are more apologetic, telling police their relationship with women
• Significance of time and place

  Indications of where the offender lives
• Forensic awareness

  Focuses on individuals already in the system e.g. "covering tracks" indicates experience in crime
• Evaluating the top-down approach

  Weakness

  • The top-down approach was developed based on interviews with 36 killers in the USA. This sample is small and unrepresentative to base an entire approach on. Furthermore, it is not sensible to rely on self-reports from this sample because the serial killers cannot be relied upon to give accurate information
  • This is a weakness because it suggests the results cannot be generalised to the wider population, especially as the self-reports cannot be relied on for validity
  • Therefore, the top-down approach may not be appropriate for use with all cases
• Investigative psychology - evaluation

  • Canter and Heritage conducted a content analysis of sexual assault cases. The data was analysed using the statistical technique, identifying correlations across patterns of behaviour
  • Several characteristics were identified as common in most cases such as the use of interpersonal language
  • This can lead to an understanding of how behaviour can change over a series of offences
  • Supports the usefulness of investigative psychology as it shows how statistical techniques can be applied
• Geographical profiling

  Based on the principle of spatial consistency (offender's operational base and possible future offences are revealed by the location of their previous crimes, aka crime mapping)
• Circle theory

  • The marauder - operates in close proximity to their home base
  • The commuter - likely to have travelled away from home
  • The pattern of offending forms a circle around their home
  • Spatial decision-making offers insight into the nature of the offence: planned or opportunistic
  • Also reveals facts about the offender: 'mental' maps, mode of transport, employment status and age
• Circle theory - supporting evidence

  Lundrigan and Canter (2001)


  • Collected information from murder cases involving serial killers
  • Analysis revealed spatial consistency in the behaviour of the killers
  • The location of each disposed body created a centre of gravity in which the offender's base was located
  • Supports the claim that spatial information is key in determining the base of the offender
• Investigative psychology - supporting evidence

  The railway rapist

  • John Duffy carried out 24 sexual attacks and 3 murders on women near railway stations in North London in the 1980s
  • Canter analysed geographical information from the crime scenes and combined them with similar cases from the past and was able to draw up an extremely accurate profile of Duffy, leading to his arrest
  • Real-life example of investigative psychology and geographical profiling
  • Supports the use of these techniques as they are proven to have real-life application, proving their reliability
• Evaluating the bottom-up approach

  Supporting evidence

  • Lundrigan and Canter (2001)
  • Means that spatial information and statistical analysis are key factors in determining the base and characteristics of an offender
  • This research supports the effectiveness of the bottom-up approach in offender profiling
• Evaluating the bottom-up approach

  Real-world application / undermining evidence

  • The railway rapist supports the bottom-up approach whilst Rachel Nickell's case shows it doesn't always work
  • Suggests that the effectiveness of offender profiling is mixed
  • Shows that investigators cannot entirely rely on these techniques in all cases
• Evaluating the bottom-up approach

  Strength

  • Arguably more objective and scientific than the top-down approach
  • More grounded in psychological theory and evidence rather than hunches
  • Easier to rely on the bottom-up approach as it is more evidence-based
  • Top-down is highly intuitive and requires speculation
  • The ability to rely on evidence makes it easier to apply to real-life cases
• Evaluating the bottom-up approach

  Strength

  • Can be applied to a wide range of offences
  • Statistical analysis and spatial consistency can be used to investigate crimes such as burglary and theft as well as more serious crimes
  • Suggests that this approach has a wider range of real-life application - it can be used in all types of cases, making it more applicable than the top-down approach
• Top-down vs bottom-up

  Difference

  • The types of crime they are used for
  • Top-down is used for more serious crimes whereas bottom-up can be used for all kinds of crime
  • This means that the bottom-up approach may be better to use in most cases due to its wider range of application, however the top-down method can be used as a more specialised method for serious offences
• Top-down vs bottom-up

  Similarity

  • Both analyse the crime scene
  • Top-down analyses the crime scene with a pre-existing profile of what characteristics offenders may have
  • Similarly, bottom-up uses the crime scene to develop a profile
  • Means that both approaches use the crime scene to aid in their development of the profile
• Biological explanations

  • Atavistic form
  • Genetic
  • Neural
• Atavistic form

  • Lombroso observed the physical appearance of Italian prisoners and concluded that criminals were "genetic throwbacks" - a primitive subspecies
  • Argued that criminals are born, not made
  • Used the term "atavism" to describe how some individuals devolve to become more primitive (leading to crime as they cannot adjust to the demands of society)
  • List of physical features were determined by examining the skulls of 383 dead and 3,839 living criminals and included a narrow, sloping brow, a strong jaw, high cheekbones, facial asymmetry, dark skin, etc.
• Atavistic form - evaluation

  Strength of the explanation

  • Lombroso is credited in shifting the emphasis in crime research away from moral explanations (e.g. weak-minded) and towards a more scientific and credible idea (evolution and genetics) - the beginning of offender profiling
  • Emphasises the importance of using evidence
  • Influential in the development of criminology, increasing credibility
• Atavistic form - evaluation

  Weakness of the explanation

  • Elements of Lombroso's work viewed as racist - features such as curly hair and dark skin are prominent in those of African descent. His description of atavistic as savage and uncivilised would lend support to eugenic philosophies at the time that those of African descent were unfit to breed
  • Reinforces racist stereotypes at the time, essentially labelling those of African descent as savage and uncivilised due to the colour of their skin and hair type
  • Means there are controversial factors to using biology to explain crime
• Atavistic form - evaluation

  Limitation of research / undermining evidence

  • Lombroso did not compare his results with a control group and did not consider other variables: psychological disorders
  • A limitation because the theory is based on flawed evidence, lacking objectivity
  • Goring compared 3,000 criminals and 3,000 non-criminals, concluding no evidence that offenders were a distinct group with unusual physiology
  • The results of the research question the main idea that criminals are physiologically different
  • Means that other biological explanations should be considered
• Genetic

  • Modern genetics suggests that if our nervous system is dependent on our genes, then our behaviour may be influenced by genes
  • Genetic theories on crime assume behaviour is influenced by several genes which must interact with the environment
• Twin studies

  • Lange (1930)

  Method

  • 13 monozygotic and 17 dizygotic twins
  • One twin in each pair served time in prison

  Findings

  • 10 of the monozygotic twins had a co-twin who was also in prison
  • 2 of the dizygotic twins had a co-twin in prison

  Conclusion

  • Shows genetic factors must play a predominant part in offending behaviour

  Evaluation

  • Poorly controlled
  • Lacks validity - judgements on whether they were mono/dizygotic based on appearance rather than DNA tests
  • Lack of generalisability - unusual sample
  • Confounding variable - most twins from the same environment
• Adoption studies

  • Crowe (1972)
  • Found adopted children had a 50% risk of having a criminal record by 18 if the parents also had one
  • Adopted children whose mother didn't have a criminal record only had a 5% risk

  Evaluation

  • Validity - many children spent time with their biological parents before being adopted, or still keep in contact with them so it is difficult to assess the environmental impact the biological parents had
  • Medrick et al. (1984) - figures only applied to petty crimes
  • Any conclusions drawn cannot be applied to more serious crime
• Candidate genes

  • Tiibonen et al. (2014)
  • Abnormalities in 2 genes may be associated with violent crime
  • MAOA (controls dopamine and serotonin) - linked to aggressive behaviour
  • CDH13 - linked to substance abuse and ADHD
  • Within the Finnish sample, individuals with the high-risk combination were 13x more likely to have a history of violent behaviour

  Evaluation

  • Reliability - research has not been replicated
• Diathesis-stress model


  • If genetics have an influence on offending, it is likely that it is partly moderated by the effects of the environment
  • Model has been applied to schizophrenia
  • Tendency towards offending may be a combination of biological and environmental factors
• Diathesis-stress model

  Support

  • Medrick et al. (1984)
  • 13,000 Danish adoptees
  • Criminal behaviour defined as 1+ court conviction, checked against Danish police records
  • Biological and adoptive parents had no convictions: 13.5% of adoptees had convictions
  • Only biological parents had a conviction: 20% of adoptees had convictions
  • Both biological and adoptive parents had convictions: 24.5% of adoptees had convictions
  • Although genetic inheritance plays a role, environmental factors cannot be disregarded
• Genetic explanations of offending behaviour

  Evaluation - weakness

  • Lange's research was poorly controlled and judgements on mono/dizygotic was based on appearance, not DNA tests
  • Furthermore, monozygotic twins share a more similar environment than dizygotic twins as people tend to treat them more similarly
  • Research lacks validity as the judgements were made based on appearance - lacks credibility as it is not scientific
  • Further lacks validity - twins often raised in the same environment so confounding variables are not controlled
  • Shows that environmental factors must be considered
• Genetic explanations of offending behaviour

  Evaluation - supporting evidence

  • Adoptions studies have shown that the % convictions in adoptees was highest when both adoptive and biological parents also had convictions
  • Shows a basis of genetic influence as when biological parents have a conviction, the % of adoptees who do too increases from 13.5% to 20%
  • However, the increase to 24.5% when both biological and adoptive parents have convictions supports the diathesis-stress model
  • Again proves that environmental factors cannot be discarded
• Neural

  • Evidence suggests there may be neural differences in the brains of criminals
  • Study of individuals with APD, associated with reduced emotional responses and a lack of empathy