forensic psychology Flashcards
define offender profiling
investigate tool to help police when solving crimes
careful scrutiny of the crime scene and analysis of evidence to help propose a hypothesis of the potential characteristics of the offender
what is the American approach to offender profiling
the top-down approach
as a result of work carried out by the FBI in the 1970s
the FBI’s behavioural science unit drew upon data from in-depth interviews with 36 sexually motivated killers e.g. Ted Bundy
define the top-down approach
profiles start with a pre-established typology
will match what is known about the crime and the offender to a pre-existing typology that the FBI developed
they work down in order to assign offenders to one of two categories based on witness accounts and evidence from the crime scene
e.g. organised or disorganised
on the basis of the evidence `and this classification informs the subsequent police investigation
define organised offenders
show evidence of having planned the crime in advance
deliberately targeted and will often reflect the criminal has a ‘type’ of victim
maintain a high degree of control and may operate with almost detach surgical precision
little evidence or clues left
above-average intelligence
in a skilled professional occupation, married and are socially and sexually competent
define disorganised offender
show little evidence of planning
may have been spontaneous
crime scene tends to reflect the impulse nature of the attack
little control on the part of the offender
lower than average IQ unskilled, history of sexual dysfunction and failed relationships
tend to live alone close to where the offence took place
what are the 4 main stages of constructing an FBI profile
data assimilation - profiler reviews the evidence
crime scene classification - as either organised or disorganised
crime reconstruction - hypotheses in terms of sequence of events
profile generation - hypotheses related to the likely offender
evaluation of top-down approach
only applies to particular crimes
the approach Is best suited to crime scenes that reveal important details about the suspect e.g. rape and arson as well as crimes that involve macabre practices such as torture
more common offences such as burglary and destruction of property do not lent themselves to profiling because the resulting crime scene reveals very little about the offender
means its a limited approach to identifying a criminal
evaluation of top-down approach
based on outdated models of personality
the typology of classification is based on the assumption that offenders have patterns of behaviour and motivations that remain consistent across situations and contexts
several critics Alison et al 2002 have suggested this approach is naive and is informed by old-fashioned models of personality that see behaviour as being driven by stable dispositional traits rather than external factors that may be constantly changing
means the top-down approach which is based on static models of personality is likely to have poor validity when it comes to identifying possible suspects and/or predicting their next move
evaluation of top-down approach
evidence does not support the disorganised offender
Canter et al 2004, using a technique called smallest space analysis analysed data from 100 murders in the USA
details of each cases were examined with reference to 39 characteristics thought to be typical of organised and disorganised killers
although findings did suggest evidence of a distinct organised type, this was not the case for disorganised which seems to undermine the classification system as a whole
define the bottom up approach
the aim is to generate a picture of the offender - their likely characteristics, routine behaviour and social background
through systematic analysis of evidence at the crime scene
this is the British approach, does not begin with fixed typologies
instead the profile is data driven and emerges as the investigator engages in deeper and more rigorous scrutiny of the details of the offence
more grounded in psychological theory
define investigative psychology and its role in bottom-up approach
investigate psychology is an attempt to apply statistical procedures alongside psychological theory, to the analysis of the crime scene evidence
the aim is to establish patterns of behaviour that are likely to occur or co-exist across crime scene
this is in order to develop a statistical database which then acts as a baseline for comparison
specific details can then be matched agaisint this database to reveal important details about the offender
central to the approach is concept of interpersonal coherence- that the way an offender behaves at the scene, including how they interact with the victim
significance of time and place are key variables
forensic awareness describes those individuals who have be subject to police interrogation before, behaviour may denote how mindful they are of covering their tracks
define geographical profiling
frist described by Kim Rossmo 1997
uses information to do with the location of linked crime scenes to make inferences about the likely home or operational base of an offender -crime mapping
it can be used in conduction with psychological theory to create hypotheses about how the offender is thinking as well as their modus operandi
assumption is that serial offenders will restrict their work to geographical areas they are familiar with, as so understanding spatial pattern of their behaviour provides investigators with a centre of gravity which is likely to include the offenders base
may also help investigators make educated guesses about where the offender is likely to strike next
define Canter’s circle theory
for the bottom up approach
Canter and Larkin 1993 proposed two model of offender behaviour
the marauder - who operates in close proximity to their home base
the commuter - who is likely to have travelled a distance away from their usual residence
pattern of offending is likely to form a circle around their usual residence and this becomes more apparent the more offences there are
evaluation of bottom-up approach
evidence supports investigative psychology
Canter and Heritage 1990 conducted a content analysis of 66 sexual assault cases
the data was examined using the statistical technique smallest space analysis - a computer program that identifies correlations across patterns of behaviour
several characteristics were identified as common is most cases, e.g. the use of impersonal language and a lack of reason to the victim
these characteristics will occur in different patterns in different people
evaluation of bottom-up approach
evidence supports geographical profiling
Lundrigan and Canter 2001 collated information from 120 murder cases involving serial killers in the USA
smallest space analysis revealed spatial consistency in the behaviour of the killers
the location of each body disposal site was in a different location from the previous sites, creating a centre of gravity, the offenders base was invariably located in the centre of the pattern
the effect was more noticeable for offenders who travelled short distances - marauders
supports canter’s claim spatial information is a key factor in determining the base of an offender
evaluation of bottom-up approach
scientific basis
Canter’s argument is that bottom up profiling is more objective and scientific than the top down approach as it is more grounded in evidence and psychological theory and less driven in speculation and hunches
Eysenck’s theory of the criminal personality
general personality theory
Eysenck 1947 proposed that behaviour could be represented along 2 dimensions
introversion/extraversion E and neruoticism/stability N
the two dimensions combine to form a variety of personality characteristics or traits
Eysenck later added a third dimension -psychoticism P
Eysenck’s theory of the criminal personality
biological basis
our personality traits are biological in original and come about through the type of nervous system we inherit
thus all personality types including the criminal personality type have an innate biological basis
extraverts have an underachieve nervous system which means they constantly seek excitement and stimulation
they tend not to condition easily and don’t learn from mistakes
neurotic individuals tend to be nervous jumpy and over anxious
what did Eysenck think the criminal personality was
the type was neurotic-extravert
a combination of all the characteristics and behaviours described above for both neuroticism and extraversion
he suggested that typical offenders will also score highly on measures of psychoticism a personality characterised as cold and prone to aggression