forensic psychology Flashcards
offending profiling
- a tool used by police/investigators to try and narrow the field of likely suspects
- usually involves careful scrutiny of a crime scene and analysis of evidence (including witness reports)
- this allows the probable characteristics of the offender to be generated
what are the two types of offender profiling?
- top-down
- bottom-up
development of top-down profiling
- began in the US
- came about due to FBI work in the 70s
- specifically due to FBIs data gathered from in-depth interviews with 36 sexually motivated serial killers (including Ted Bundy and Charles Manson)
What is the top-down approach to offender profiling?
- also known as the ‘typology approach’ for its use of categories (organised and disorganised)
- involves matching what is known about the crime and the offender to a pre-existing template developed by the FBI
- murderers or rapists are classified (pushed down) into either organised or disorganised categories based on evidence
- this classification is just one part of the top down approach.
organised - crime scene
- evidence of having planned crime
- little evidence left at scene
- victim is deliberately targeted, offender has a “type”
- high degree of control
organised - offender
- high IQ
- may even be married with children
- skilled professional occupation
- socially and sexually competent
- go to inordinate lengths to cover their tracks and are often forensically savvy
- likely to follow the news media reports of their crime and may even correspond with the media
disorganised - crime scene
- reflects impulsive nature of the attack eg. body left, semen, blood, fingerprints
- victim not known, selected at random
- little evidence of planning, spontaneous/spur of the moment
disorganised - offender
- lower than average IQ
- unskilled work or profession
- sexually incompetent, failed relationships, socially incompetent
- live alone, often close to where the offence took place
eg. ted bundy (organised offender)
> known to have raped, tortured and brutally murdered over 30 women
charming and highly intelligent, would win the trust of victims
many of his victims resembled his college girlfriend who broke up with him (long, dark hair parted in the middle) - his “type”
skilled profession (law)
socially and sexually competent
evaded the police for years (even escaping twice)
constructing an FBI profile
- Data assimilation
- Crime scene classification
- Crime reconstruction
- Profile generation
data assimilation
(1st stage of constructing a profile)
investigators gather information from multiple sources eg. crime scene photos, police reports, etc.
crime scene classification
(2nd stage of constructing a profile)
decide whether the crime scene represents an organised or disorganised offender
crime reconstruction
(3rd stage of constructing a profile)
hypotheses are generated about what happened during the crime such as victim behaviour
profile generation
(4th stage of constructing a profile)
4. profilers construct a “sketch” of the offender including physical and behavioural characteristics
the bottom-up approach
- Profilers work up from evidence collected from the crime scene to develop hypothesis about the likely characteristics, motivations, and social background of the offender
- The profile is “data driven”
- No initial assumptions are made about the offender and the approach relies heavily on computer databases
- the “British” approach to offender profiling
what can the bottom-up approach be divided into?
- investigative psychology
- geographical profiling (used with investigative)
what is investigative psychology?
- tries to apply statistical procedures to analyse the crime scene
- establishes patterns of behaviour that seem to occur across crime scenes
- creates a database for baseline comparisons
- specific details of an offence can then be matched against the database to reveal important details about the offender, their personal history, family, background, etc.
- cases can be linked together if the evidence tells us that they seem related
what are the three main features of investigative profiling?
- Interpersonal coherence
- Forensic awareness
- The significance of time and place
interpersonal coherence
- people’s behaviour is consistent so their crime will contain indicators of their everyday life eg. if they are violent against women
forensic awareness
- have they been in trouble with the police before, do they know how to cover their tracks
> Davies et al (1997) found rapists who conceal their fingerprints often have a previous conviction of burglary
the significance of time and place
- where are the crimes committed? Does this correlate with where an offender might live?
what did Canter propose (G. profiling)
- offenders reveal themselves through the locations they commit crimes in
- often restrict their crimes to places they are familiar with (often near where they live or habitually travel)
how is geographical profiling useful?
- provides investigators with a ‘centre of gravity’ which is likely to include the offender’s base (becomes more apparent with more offences)
- may also help to make educated guesses about where the offender is likely to strike next - the ‘jeopardy surface’
- to work out the nature of the offence (planned or opportunistic)
- to work out the offenders mental ‘map’, mode of transport, employment, etc.
geographical profiling
- G. profiling analyses the locations of connected series of crimes, considering:
1. where they are committed
2. the spatial relationships between each scene
3. how they might relate to an offenders place of residence
Canter’s circle theory
(Canter and Larkin 1993) proposed two models of offender behaviour:
1. the marauder - operates near their home base
2. the commuter - likely to have travelled a distance away from their usual residence
how does geographical profiling link to schemas?
understanding and feeling comfortable, comfort zones around work/our home, etc.
evaluation of the bottom up approach
+ works for more offences than the top-down approach
+ scientific and objective, focused on data
+ supporting evidence - Canter and Lundrigan collated info from 120 murder cases involving serial killers in the US, they found spatial consistency in where bodies were disposed
- just because someone fits the profiler does not mean they are the offender (eg. Colin Stagg was falsely taken to court for sexually assaulting and repeatedly stabbing Rachel Nickel in 1992, 17 years later the real perpetrator - who had been dismissed due to being “too tall” was convicted)
the atavistic form
- created by Lombroso in 1870
- suggested that offenders are ‘genetic throwbacks’ a primitive sub-species that are ‘biologically’ different to non-criminals
- such individuals are ill-suited to conforming to the rules of modern society
- this criminal sub-type could be identified as being in possession of ‘physiological markers’ that were linked to types of crime
types of criminals and their characteristics according to Lombroso
Murderers - eg. blood shot eyes, curly hair, long ears
Sexual deviants - eg. glinting eyes, swollen fleshy lips, projecting ears
Thieves - eg. expressive face, manual dexterity, small wondering eyes, thin and reedy lips
Women - eg. shorter and more wrinkled, darker hair and smaller skulls than ‘normal’ women
what characteristics did Lombroso identify as being indicators of criminality?
a narrow, sloping brow
a strong prominent jaw
high cheekbones
facial asymmetry
dark skin
existence of extra toes, nipples, or fingers
insensitivity to pain
use of primeval slang (a throwback to their savage ancestry)
tattoos
unemployment
(10)
“Lacking evolutionary development, their savage and…”
“Lacking evolutionary development, their savage and untamed nature meant they would find it impossible to adjust to the demands of civilised society and would inevitability turn to crime.” - Lombroso
Lombroso’s “evidence”
‘I investigated the facial/cranial/physical features of hundreds of Italian convicts both living and dead. After examining the skulls of 3839 living criminals, and 383 dead criminals I concluded that 40% of crimes were accounted for by ativistic characteristics’
He measured weight, height, span of their arms, average seated height, hand size, necks, thighs, legs, feet, eye colour, etc.
> only looked at criminals, no comparison to a control group so could also be true for non-criminals
genetic explanations for criminality
One or more genes predispose (create vulnerability) in individuals leading to criminal behaviour. However, there hasn’t been a ‘criminal gene’ identified.
1. twin studies
2. candidate genes
twin studies to explain criminality
- if there is a higher concordance rate in MZ twins then this suggests that genetics has an influence.
- eg. Lange (1930) found significantly higher concordance rates for criminality in identical twins than non-identical twins
- eg. Raine reviewed research on delinquent behaviour of twins and found 52% concordance for MZ twins and 21% for DZ twins.
- However, identical twins will also share very similar environment so it is hard to separate genetics from environment.
Lange (1930)
- investigated 13 identical twins and 17 non-identical twins, where one of each of the twins in each pair had served time in prison
- found that 10 of the identical twins but only two of the non-identical twins had a co-twin also in prison.
- This suggests that there is a genetic factor to criminality.
Raine (1993)
- reviewed research on delinquent behaviour of twins
- found 52% concordance for MZ twins and 21% for DZ twins.
candidate genes to explain criminality
- low levels of the MAOA gene have been linked to aggression/impulsive behaviour
> However, this works in combination with the environment rather than on its own - low activity of the CDH13 gene - has been associated with ADHD and substance abuse
MAOA gene (criminality)
- low levels of the MAOA gene which is linked to the break down of neurotransmitters in the brain (eg. serotonin, dopamine, and noradrenaline)
- therefore linked to aggression/impulsive behaviour
> However, this works in combination with the environment rather than on its own
CDH13 gene (criminality)
low activity of the CDH13 gene has been associated with ADHD and substance abuse which are both strongly associated with criminality
> hard to be sure of cause and effect
Brunner - criminal behaviour
Brunner studied 28 male members of a Dutch family who had histories of impulsive and violent criminal behaviour such as rape and attempted murder. When Brunner analysed the DNA of these men it was found that they shared a gene that led to low MAOA levels.
Moffitt et al. (1992)
conducted a longitudinal study on 443 New Zealander males recording which participants had been abused as children and what level of MAOA gene they had.
Abuse + low activity MAOA = 9x more likely to be aggressive.
the diathesis stress model for criminality
This considers the vulnerability (the diathesis) along with stressors in the environment. Eg. maltreatment in childhood (an environmental factor) could lead to criminality if individuals have low MAOA gene
> Caspi (2002) found higher risk of antisocial behaviour and aggressive adults in those with the MAOA gene who had also experienced maltreatment.
Evaluation of the biological explanation for criminality
+ supporting evidence eg. Lange’s twin study
> issues with twin study evidence, they have very similar environments so it is difficult to be sure
- Mednick et al (1984) studied 13000 Danish adoptees and found that it is not just bio factors
- over-simplifying, possibly reductionist
- implications for the legal system and for moral responsibility
Lange’s twin study
found that identical twins in prison were more likely than non-identical twins to have a twin also in prison
> issues with twin study evidence, they have very similar environments so it is difficult to be sure that the findings suggest a biological basis
Mednick et al (1984)
studied 13000 Danish adoptees and found that:
- when neither the bio or adoptive parents had convictions, percentage of criminals was 13.5%
- when a bio parent had convictions this rose to 20%
- 24.5% when both adoptive and biological parents had convictions
Eysenck’s criminal personality
- believed that criminal behaviour had a biological basis, that it was influenced by genetics and the structure of an individual’s inherited, predisposing nervous system
- but also that personality was an innate function which could link to criminality
- ‘trait theory’
‘trait theory’
- Eysenck
- if you have certain ‘traits’, you may have a criminal personality:
1. high extroversion
2. high neuroticism
3. (added later) high psychoticism