Forensics - Bottom Up Approach Flashcards
What is the bottom-up approach?
Profilers work up from evidence collected from the crime scene to develop hypotheses about the likely characteristics, motivations, and social background of the offender.
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.
How does investigative psychology work?
Investigative psychology attempts to apply statistical procedures, alongside psychological theory, to the analysis of crime scene evidence. It aims to establish patterns of behaviour that are likely to occur or co-exist across crime scenes. This helps to develop a database, which can then act as a baseline for comparison. Specific details about the offender, such as their family background, etc., may also be identified from this database.
What is geographical profiling?
A form of bottom-up profiling based on the principle of spatial consistency; that an offender’s operational base and possible future offences are revealed by the geographical location of their previous crimes.
What is the principle behind geographical profiling?
Geographical profiling is based on the idea of spatial consistency – that the offender’s operational base and possible future offences can be inferred from the geographical location of their previous crimes. It uses the circle theory of environmental range (Canter and Larkin, 1993), which distinguishes between ‘marauders’ (those who operate close to their home base) and ‘commuters’ (those who travel away from their usual base).
What is one evaluation point supporting investigative psychology?
David Canter and Rupert 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 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 offender’s behaviour may change over a series of offences or in establishing whether two or more offences were committed by the same person. This supports the usefulness of investigative psychology because it shows how statistical techniques can be applied.
What is one evaluation point supporting geographical profiling?
Samantha Lundrigan and David 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 direction from the previous sites, creating a ‘centre of gravity’; the offender’s base was invariably located in the centre of the pattern. The effect was more noticeable for offenders who travelled shorter distances (‘marauders’). This supports Canter’s claim that spatial information is a key factor in determining the base of an offender.
What is one evaluation point on the scientific basis of the bottom-up approach?
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 by speculation. With the aid of advanced artificial intelligence, 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 areas such as suspect interviewing and examination of material presented in court, which supports its utility in all aspects of the judicial process.
What is one evaluation point on the mixed results of profiling?
Despite the many successes that the bottom-up approach to profiling has provided, there have been some significant failures. For example, Copson (1995) surveyed 48 police forces and found that the advice provided by the 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. Similarly, Kocsis et al. (2002) found that chemistry students produced a more accurate offender profile on a solved murder case than experienced senior detectives. This suggests that while bottom-up profiling may have potential, it is not without its limitations.
