Bottom-up approach

• What is the bottom-up approach?

  • Developed by David Canter in the UK, main aim being to generate a picture of the offender and their likely characteristics through systematic analysis of crime scene evidence
  • Doesn't begin with fixed typologies like the top-down approach, profile is data-driven and more grounded in psychological theory
• What is investigative psychology?

  • Combines statistical analysis with psychological theory to analyse crime scenes, aiming to establish patterns of behaviour that are likely to co-occur across crime scenes
  • Leads to the creation of a statistical database that serves as a baseline for comparing different crimes
• What are 3 aspects central to the bottom-up approach?

  • Interpersonal coherence: how the offender interacts with the crime scene and the victim reflects their everyday behaviour
  • Significance of time & place: where the crime takes place may indicate where the offender lives
  • Forensic awareness: criminal's behaviour may be indicative of previous criminal experience e.g. covering up the crime scene due to being interrogated by the police before
• What is geographical profiling?

  • Rossmo (1997) proposed 'crime mapping' which uses information about the location of linked crime scenes to make inferences about the likely home of the offender
  • Can be used to predict where the criminal is next likely to commit a crime known as 'jeopardy surface'
  • Can also provide 'mental maps' of areas the criminal knows well and has experience with, and an insight into premeditation, modes of transport, etc.
• What is Canter's circle theory?

  • Canter and Larkin (1993): suggest that patterns of offending usually form circles around an offender's residence, proposing 2 models used to describe offenders
  • Marauder - operates in close proximity to home due to great familiarity with the area and will try to disguise identities
  • Commuter - will travel far away from his residence and not care about hiding their identities
• What is one strength of the bottom-up approach?

  • Research support for investigative psychology: Canter and Heritage (1990) conducted a smallest space analysis (identifies correlations across different samples of behaviour) on 66 sexual assault cases
  • Found several common behaviours such as the use of impersonal language that could help establish whether 2 or more offences were committed by the same person, known as 'case linkage'
  • Supports interpersonal coherence and use of statistical techniques in identifying behaviour patterns, strengthening investigative psychology
• What is another strength of the bottom-up approach?

  • Research support for geographical profiling: Lundrigan and Canter (2001) conducted a smallest space analysis on 120 murder cases by serial killers - found spatial consistency where the killer disposed of the body in various locations that formed centres of gravity with the offender's residence in the middle
  • Supports geographical profiling in identifying offenders
• What is one limitation of the bottom-up approach?

  • Mixed results: Copson (1995) surveyed 48 police departments and found that 83% of responses said it gave useful advice suggesting it is a valid investigate tool
  • BUT the same study revealed that only in 3% of cases did it reveal the accurate identity of the offender
  • Kocsis et al. (2002) found that chemistry students produced more accurate profiles on a solved murder case than experienced senior detectives - weakening the usefulness of the bottom-up approach
• What is another limitation of the bottom-up approach?

  • Rachel Nickell was murdered in 1992 and the police enlisted offender profiler Paul Britton, whos' profile was narrow and incorrect as the real murderer was ruled out of the enquiry due to being several inches taller than the profile
  • Shows that there is a high risk of pursuing innocent suspects and letting criminals run free for a long period of time e.g. Robert Napper killed and raped more women due to being uncaught