Lesson 2 - Bottom Up Approach Flashcards
What is the aim of the Bottom Up approach
The bottom-up approach was developed in the UK, the aim of this approach is to generate a picture of the offender, including their likely characteristics, routine behaviour, and social background. This is achieved through systematic analysis of evidence left at the crime scene
How does the Bottom Up approach operate
The bottom-up approach does not begin with fixed typologies (as the top down approach does), instead the profile is data-driven and emerges as the profiler engages in rigorous scrutiny of the details of the offence. Bottom-up profiling is far more grounded in psychological theory than the top-down approach.
What is the aim of investigative psychology (Bottom Up)
The aim of investigative psychology is to establish behaviours that are likely to occur at certain crime scenes. This is done in order to create a statistical database which then acts as a baseline for comparison. Specific details of an offence can then be matched against this database in order to reveal statistically probable details about the offender (their personal history, family background etc.). This can also help determine whether multiple offences are linked and likely to have been committed by the same individual.
What is interpersonal coherence (Bottom Up)
Central to investigative psychology is the concept of interpersonal coherence. The way in which an offender behaves at the crime scene, including how they interact with the victim, may reflect their behaviour in everyday situations. For example, whilst some rapists want to control and humiliate their victim, others can be apologetic. This might tell the police how the offender relates to women more generally.
Significance of time and place (Bottom Up)
The significance of time and place of the crime is also a key variable and may indicate where the offender lives.
What is forensic awareness (Bottom Up)
Forensic awareness describes individuals who have made an attempt to ‘cover their tracks’ (i.e. hide the body/murder weapon or clean the crime scene). Their behaviour may indicate that they have been the subject of police interrogation in the past, or even that the police already have their DNA or fingerprints on file.
What is geographical profiling (Bottom Up)
Geographical profiling is the study of spatial behaviour in relation to crime and offenders. It focuses on the location of the crime as a clue to where the offender lives, works and socialises. Relevant data includes the crime scene, local crime statistics, local transport, and geographical spread of similar crimes.
Assumptions of geographical profiling (Bottom Up)
The assumption is that a serious offender will restrict their criminal activities to an area that they are familiar with, and the offender’s base will therefore be in the middle of the spatial pattern of their crime scenes. Earlier crimes are likely to be closer to the offender’s base than later crimes. As an offender becomes more confidence they will often travel further from their comfort zone.
What are two models of offender behaviour (Bottom Up)
Canter and Larkin (1993) propose two models of offender behaviour: the marauder and the commuter
Marauder (Bottom Up)
The marauder operates close to their home
Commuter (Bottom Up)
The commuter is likely to have travelled a distance away from their home
Similarity between marauder and commuter (Bottom Up)
Crucially, though, the spatial pattern of their crime scenes will still form a circle around their home. This becomes more apparent the more offences that are committed.
What else can the spatial pattern of a crime tell (Bottom Up)
The spatial pattern of a crime can also tell the police whether the crime was planned or opportunistic, as well as other important facts about the offender such as their mode of transport, employment status, approximate age, etc.
Strengths of the Bottom Up approach
Canter argues that bottom-up profiling is more scientific than top-down profiling because it is more grounded in evidence and psychological theory and less driven by speculation and hunches than top-down profiling.
Bottom-up profiling, unlike top-down profiling, can be applied to a wide variety of offences, such as burglary and theft, as well as murder and rape.
Weaknesses of the Bottom Up approach
There have been some significant failures when using bottom-up profiling. In 1992, 21 year old Rachel Nickell was stabbed 47 times and sexually assaulted in a frenzied attack on Wimbledon Common. In 2008, following examination of forensic evidence, Robert Napper was convicted of the murder. He had been ruled out early on in the initial investigation because he was several inches taller than the profile had claimed the offender would be.
Copson (1995) surveyed 48 police forces and found that the advice provided by a profiler was judged to be useful in 83% of cases, but in only 3% of cases did it lead to the accurate identification of the offender.
Kocsis et al. (2002) found that chemistry students produced a more accurate offender profile than experienced senior detectives. This implies that the bottom-up approach is little more than common sense and guess work
