2. bottom up approach Flashcards
what is the aim of the bottom up approach
to generate a picture of the offender - their likely characteristics, routine behaviour and social background - through systematic analysis of evidence at the crime scene.
how is the bottom up approach different to the top down 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.
bottom up profiling is also much more grounded in psychological theory than the top down approach.
what is investigative psychology
a form of bottom up profiling that matches details from the crime scene with statistical analysis of typical offender behaviour patterns based on psychological theory.
what is the aim of investigative psychology
to establish patterns of behaviour that are likely to occur or coexist across crime scenes. this is in order to develop a statistical data base which then acts as a baseline for comparison.
specific details of an offence can then be matched against this database to reveal important details about the offender (personal history and family background). this may also determine whether a series of offences are linked in that they are likely to have been committed by the same person.
what is interpersonal coherence
the way an offender behaves at the scene including how they interact with the victim as this may reflect their behaviour in more everyday situations. for instance whilst some rapists want to maintain maximum control and humiliate their victims, others are more apologetic - this might tell the police something about how the offender relates to women more generally.
what are two key variables of investigative psychology
time and place - as in geographical profiling it may indicate where the offender is living.
what is forensic awareness
describes those individuals who have been the subject of police interrogation before - their behaviour may denote how mindful they are of covering their tracks.
what is geographical profiling
uses information to do with the location of linked crime scenes to make inferences about the likely home or operational base of an offender - known as crime mapping.
it can also be used in conjunction with psychological theory to create hypotheses about how the offender is thinking as well as their ways of working.
what assumption does geographical profiling make
serial offenders will restrict their work to geographical areas they are familiar with and so understanding the spatial pattern of their behaviour provides investigators with a centre of gravity which is likely to include the offenders base (often in the middle of the spatial pattern).
may also help investigators make educated guesses about where the offender is likely to strike next - called the jeopardy surface.
what did canter circle theory propose
two models of offender behaviour:
marauder = operates in close proximity to their home base.
commuter = likely to have travelled a distance away from their usual residence.
crucially the pattern of offending is likely to form a circle around their usual residence and this becomes more apparent the more offences there are. such spatial decision making can offer the investigative team important insight into the nature of the offence (whether it was planned or opportunistic) as well as revealing other important factors about the offender (mode of transport and employment status and approximate age).
what research support is there for investigative psychology
canter and heritage 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 in most cases such as the use of impersonal language and lack of reaction to the victim - these characteristics will occur in different patterns in different individuals. this can lead to an understanding of how an offenders behaviour may change over a series of offences or in establishing whether two or more offences were committed by the same person = supports the usefulness of investigative psychology because it shows how statistical techniques can be applied.
what research support is there for geographical profiling
lundrigan and canter 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 direction 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 canters claim that spatial information is a key factor in determining the base of an offender.
how does scientific basis support the bottom up approach
canters 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 by speculation and hunches. with the aid of advanced AI investigators are able to manipulate geographical, biographical and psychological data quickly to produce insights and results that assist in the investigation.
similarly the field of investigative psychology has recently expanded to include such areas as suspect interviewing and examination of material presented in court which supports its utility in all aspects of the judicial process.
how is wider application a strength for the bottom up approach
techniques such as smallest space analysis and the principle of spatial consistency can be used in the investigation of crimes such as burglary and theft as well as more serious offences such as murder and rape.
