On Tuesday, renowned investigative psychologist Professor David Canter described how his commercial use of cluster analysis, combined with his development of what is now known as geographical offender profiling, led to the conviction of a serial murderer. Mel Crowther reports.
A little known aspect of Professor David Canter's career is his previous work with United Biscuits, which drew on his understanding of how to map the group decision making process, and ended with the creation of the Hobnob. During this session, he described how by mapping customers' perceptions of various biscuit brands, he uncovered a gap in the market between savouries - regarded as good and wholesome but not very interesting - and sweets - seen as enjoyable but rather naughty. From this gap, it was found that there was room in the marketplace for a 'wholesome sweet biscuit', and the Hobnob has filled this gap for decades ever since.
Behavioural analysis of cities and crime
Canter began his career as an architectural psychologist, studying the interactions between people and buildings, and exploring how people made sense of the large scale environment, notably cities. His work in this field led to him studying human reactions to fires and other emergencies and it was this combined expertise that led to the police calling upon him to help them solve a series of rapes and murders back in the mid-1980s. 'Police wanted me to help catch the man before he killed again,' Canter explained.
Profiling a criminal's personality and traits
Police had based their investigations on victims' verbal reports, but Canter decided to approach the problem from a systematic and scientific standpoint, using the same system he had employed when working for United Biscuits and his work on understanding geographies and cities to build a profile of the offender.
The crimes had all taken place in close proximity to railway lines in London, and having examined the details of each crime, Canter built up a profile of the attacker's personality, habits and traits. Having mapped the locations where each offence had been committed, he then produced a geographical cluster diagram from which he deduced that the criminal lived in the locality.
Further analysis led to the belief that over time, the offender's behaviour had become more determined and more planned, had moved from week days to weekends, and had probably changed from duo to solo activities.
Closing the gap
Using these analyses and the assumption that the offender lived locally, police were able to narrow down the number of suspects from several thousand, to around half a dozen. Among both the original and final group was John Duffy, a known sex offender who had previously been convicted of raping his wife, and he was ultimately convicted of the crimes that were eventually to be dubbed The Railway Murders.
After the trial, much was made of the psychological profile constructed by Canter, as Duffy fitted thirteen of the seventeen observations Canter had made about the attacker's lifestyle and habits. In addition, as Canter had predicted, it was later discovered that Duffy had been acting with accomplice and former school friend David Mulcahy.
Canter has since developed his Dragnet software to help police apply his systems, and such profiling is now commonplace in policing.
Another success for the Conference's policy of going off-topic... it may not be market research as such, but it does make for an interesting session, and get delegates thinking.
All articles 2006-20 written and edited by Mel Crowther and/or Nick Thomas unless otherwise stated.