Lecture 4: Profilling Lie Detection

The History of Criminal Profiling

• Brussel's (1968) profile of the "Mad Bomber" is considered a milestone in the origins of criminal profiling
• In the 1970s, the FBI developed a criminal profiling program, which has since been replicated internationally

Methods of Profiling

• Deductive Criminal Profiling: profiles the background characteristics of an unknown offender based on evidence left at the crime scene
  • Relies on logical reasoning, but underlying logic can be faulty
• Inductive Criminal Profiling: profiles the background characteristics of an unknown offender based on what we know about other solved cases
  • Relies on determining how likely it is an offender will possess certain background characteristics given their prevalence among known offenders

The FBI Approach

• Developed by the Behavioral Science Unit in the 1980s
• Interviews with 36 convicted sexually motivated murderers led to the distinction between Organised and Disorganised crime scenes
• Organised crime scenes: planned in advance, specific victim targeted, controlled conversation, crime scene shows signs of control, restraint used, evidence and weapon removed, body moved and hidden
• Disorganised crime scenes: spontaneous offence, victim depersonalised, minimal conversation, chaotic scene, sudden violence, little use of restraints, body left in view at scene, evidence and weapon present
• Profile of an organised offender: intelligent, socially competent, skilled job, sexually competent, lives with partner, follows details of crime in news
• Profile of a disorganised offender: average IQ, immature, poor work history, sexually incompetent, lives alone, lives near crime scene, little interest in media, little change in lifestyle after murder

Problems with the FBI Approach

• Little research has examined the model, but that which has been conducted raises serious doubts
• Cannot account for offenders who display a mix of organised and disorganised features

Statistical Approach

• Data collected from solved crimes is analysed using complex statistics
• Reveals a typology of groups of actions that tend to occur together
• Problem is that the analysis is only as good as the data fed into it, and the sample size is often too small

Geographic Profiling

• Involves an analysis of crime scene locations to determine the most probable area of offender residence
• Assumes that offenders do not travel long distances from home to commit the majority of their crimes
• Can be quite accurate in many cases

Accuracy of Profilers

• Surveys of police officers indicate profiling is useful in investigations, but only 2.6% of respondents indicated that profiles led to the identification of the offender
• Profiles often contain ambiguous advice that can be interpreted to fit a wide range of suspects

Polygraph Use

• Helps in criminal investigations, verifies a crime has occurred, and is used for pre-employment screening
• Use of polygraphs is limited in many countries, including Australia and most of Europe

Types of Polygraph Tests

• Relevant/Irrelevant Test: asks questions relevant and irrelevant to the crime
• Control Question Test (CQT): includes irrelevant, relevant, and control questions
• Guilty Knowledge Test (GKT): asks questions about specific details of the crime

Current Directions

• Voice Stress Analysis (VSA): measures changes in voice when lying, but most research has found results no greater than chance at distinguishing lying and truth-telling
• Brain-Based Lie Detection: uses electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), but results are not yet consistent enough to be admissible in court