Subliminal Salience Search Illustrated: EEG Identity and Deception Detection on the Fringe of Awareness
Howard Bowman, Marco Filetti, Dirk Janssen, Li Su, Abdulmajeed Alsufyani, Brad Wyble
We propose a novel deception detection system based on Rapid Serial Visual Presentation (RSVP). One motivation for the new method is to present stimuli on the fringe of awareness, such that it is more difficult for deceivers to confound the deception test using countermeasures. The proposed system is able to detect identity deception (by using the first names of participants) with a 100% hit rate (at an alpha level of 0.05). To achieve this, we extended the classic Event-Related Potential (ERP) techniques (such as peak-to-peak) by applying Randomisation, a form of Monte Carlo resampling, which we used to detect deception at an individual level. In order to make the deployment of the system simple and rapid, we utilised data from three electrodes only: Fz, Cz and Pz. We then combined data from the three electrodes using Fisher’s method so that each participant was assigned a single p-value, which represents the combined probability that a specific participant was being deceptive. We also present subliminal salience search as a general method to determine what participants find salient by detecting breakthrough into conscious awareness using EEG.
In the figure: ERP responses for the four critical items presented in the experiment. The concealed item (Probe) the pretented item (Fake) and the two Irrelevants. The Probe elicits a very visible response, even though participants were attempting to conceal this item. This is a type of concealed information test (CIT).