Oral Presentation: The Complex Trial Protocol, an innovative way to get to the truth

Title: The Complex Trial Protocol, an innovative way to get to the truth

Abstract:

The P300 is a well-studied electrical brainwave which appears as a positive (P) deflection on an electroencephalogram (EEG) and occurs about 300 to 600 ms (300) after a person is presented with a meaningful and novel stimulus. It is detectable by placing electrodes on the scalp of a person and it is considered as a reliable index of memory recognition, underpinned by robust scientific evidence. The leading theory of this brainwave is the orienting reflex, an involuntary psychophysiological reaction to a new and consequential stimulus. The Complex Trial Protocol is a reliable and sound methodology in analysing P300 brainwaves. In forensic circles it can be used to determine if a person involved in a crime, as a witness or a suspect, recognizes crucial pieces of information in relation to that crime and only known to the perpetrator or witness, and the authorities.
The P300 brainwave used in the context of a Concealed Information Test (CIT) can determine if that person is in possession of that crucial piece of information or not, and an inference of guilt or innocence can be drawn from such a conclusion. The CIT is easy to understand. A person is presented with a crucial piece of information (called ‘probe’) on a computer screen, such as the murder weapon, the wound pattern of a victim, the crime scene, the face of an accomplice or the face of an attacker, in the case of a victim, and it is assorted with a series of neutral alternatives (called ‘irrelevants’). Following a statistical analysis, significant spike differences, measured in microvolts, between the probe and irrelevants, provide a quantitative value of the memorial recognition value of stimuli presented.

Performed on a suspect prior to a formal interview, this memory recognition technique can easily be incorporated as a form of credibility assessment within an interview strategy. For example, if a suspect’s pre-interview test confirms the recognition of crucial stimuli only known to the author and the authorities and is followed by the suspect’s denial of the same information during the interview, the test can be a useful element for an interviewer.
Alternatively, the same test can be administered to crime witnesses. A major problem faced by law enforcement agencies worldwide is the unreliability of eyewitness identification and scarcity of physical clues at crime scenes. The body of evidence in mistaken eyewitness identification as a major contributing factor to wrongful convictions is considerable. Police agencies only collect physical evidence in approx. 15% or less of crime scenes. This relatively inexpensive and non-invasive technique is most likely to benefit law enforcement and national security agencies throughout the world in reducing erroneous suspect identification.

This presentation features the unveiling of recent data from 4 lab experiments involving autobiographical data, verbal versus pictorial stimuli and levels of processing in a mock theft scenario, and the use of multiple pictorial probe stimuli (i.e., explosive device, crime scene, and face of accomplice) in a mock terrorism scenario.