forensic: bottom up approach Flashcards
outline the bottom up approach
profilers work up from evidence collected from a crime scene to develop hypotheses about:
likely characteristics, motivation and the social background of the offender
1 - collect evidence
2 - create hypothesis
3 - identify characteristics
difference between approaches
top down begins with typologies but bottom up does not
bottom up is more grounded in psychological theory
outline investigative psychology
allows you to establish patterns of behaviour that are likely to occur or coexist across crime scene and gain information about the offender’s characteristics
what are the 3 characteristics of investigative psychology
- interpersonal coherence
- significance of time and place
- forensic awareness
outline the purpose of a statistical database
acts as a baseline for comparison
details of an offence or related offences can be matched against the database to find important details about the offender like their personal history or family background
able to determine whether a series of offences are linked and committed by the same person
define interpersonal coherence
the way an offender behaves at the scene includes:
how they “interact” with the victim
this may reflect their behaviour in everyday life
eg: some rapists may reflect their maximum control and humiliate victims, others are more apologetic (Dwyer, 2001)
define significance of time and place
may indicate where the offender is living
define forensic awareness
describes individuals who have been interrogated by police before, their behaviour may link to how mindful they are of covering their tracks
What is geographical profiling?
method that uses the locations of linked crime scenes to infer the likely home or operational base of an offender.
What principle does geographical profiling rely on
Spatial consistency, which suggests that offenders commit crimes within a limited geographical area
What are the two types of offenders in Canter’s circle theory?
- The marauder: operates close to their home base.
- The commuter: travels a distance away from their usual residence.
Why is spatial decision-making important in investigations?
It provides insights into the nature of the offence (planned or opportunistic) and reveals the offender’s mental maps, transport mode, employment status, and approximate age
AO3: evidence for investigative psychology
Canter and Heritage (1990) analysed 66 sexual assaults
The data was examined using smaller space analysis (a statistical technique that identifies correlation is across different samples of behaviour)
Several behaviours were identified as common in different samples of behaviour like use of in impersonal language and lack of reaction to the victim.
Each individual displayed a characteristic pattern that can help establish if two or more offences were committed by the same person
STRENGTH as it supports one of the basic principles of investigated psychology, that people are consistent in their behaviour
COUNTER: case linkage depends on the database and will only consist of this rhetorical crimes that have been solved the fact that they were solved maybe because it was straightforward crimes together in the first place, making this a circular argument they suggest investigative psychology tells us little about crimes that have few links and therefore remain unsolved
AO3: evidence for geographical profiling
Lundrigan and Canter (2001) collated info from 120 murder cases involving serial killers in the US
smallest space analysis revealed revealed special consistency in the behaviour of the killers
The location of each body disposal created the centre of gravity because when offenders start from their home they may go in different directions each time they dispose of a body, besides create a circular effect around the home offenders base was invariably located in the centre. This is more notable for marauders.
SUPPORTS view that geographical information can be used to identify an offender, which increases credibility of bottom up approach as it has been successful
AO3: geographical information insufficient
geographical profiling may not be sufficient on its own
more important factors could be:
- Quality of data that police can provide
- Crime rates are not accurate ( estimate of 75% are unreported
- Factors like timing of offence, age, and experience of the offender ( Ainsworth 2001)
Geographical information alone may not always lead to success for capture of the offender
