Calendar of events

Hosted by Danny Norman

3.30pm Refreshments in Common Room

Detecting Deception by Detecting Breakthrough into Awareness: a Brainwave Concealed Information Test based upon the Fringe-P3 Method

Speaker: Prof Howard Bowman (School of Psychology, University of Birmingham, Edgbaston, Birmingham B15 2TT and Centre for Cognitive Neuroscience & Cognitive Systems, School of Comp, University of Kent at Canterbury, Canterbury, Kent, CT2 7NF;

Email: H.Bowman@kent.ac.uk) Abstract: We use the term (Sub)liminal Salience Search (SSS) to describe humans' extraordinary capacity to “pre-consciously locate" stimuli that are salient to them, with the locating being in time as well as space. A particularly compelling demonstration is Rapid Serial Visual Presentation (RSVP), in which the vast majority of stimuli presented are not perceived sufficiently to make them reportable (hence the term (sub)liminal), while salient stimuli breakthrough into consciousness and can be recalled (hence the term search). Importantly, although we may experience RSVP as a jumble of “overlaid” visual stimuli, perceptual processing is highly selective, as indicated by high identification and signal detection accuracies. Within a sequence of stimuli presented via RSVP, salient stimuli can be detected using the third positivity of the Brain’s electrical response (the so-called P3), which indexes when a stimulus breaks into consciousness. RSVP, then, gives us a means to present many stimuli to a suspect and determine which were found salient using EEG (given that salient stimuli elicit P3s). The resulting Fringe-P3 method can be used as a concealed information test, since such information is typically highly salient (Bowman et al; 2013). Furthermore, the pre-conscious nature of search in RSVP makes the Fringe-P3 method especially resilient to countermeasures (Bowman et al; 2014). More specifically, the response of the brain associated with (sub)liminally identifying a salient stimulus is hard to control by conscious volitional effort. We demonstrated this by showing that the Fringe-P3 identity detector is indeed resilient to countermeasures, e.g. artificially elevating the response to control stimuli. We will also discuss our findings that famous faces presented in RSVP break into awareness and that such breakthrough can be detected with EEG on a per-individual basis. This suggests that our Fringe-P3 method can be applied across a variety of face-related forensics settings, e.g. face composite systems, line-ups, demonstrating familiarity to compatriots. Related Papers: Bowman, H., Filetti, M., Janssen, D., Su, L., Alsufyani, A., & Wyble, B. (2013). Subliminal salience search illustrated: EEG identity and deception detection on the fringe of awareness. PLoS One, 8(1), e54258. Bowman, H., Filetti, M., Alsufyani, A., Janssen, D., & Su, L. (2014). Countering countermeasures: Detecting identity lies by detecting conscious breakthrough. PloS one, 9(3), e90595. ---