Concealed information revealed by involuntary eye movements on the fringe of awareness in a mock terror experiment

Abstract

personal knowledge, without a report, to prevent deception, and to bypass an inability to report. During CIT, subjects are exposed to repeated serial stimuli, including both natural stimuli and personally significant items (termed "probes"), while their physiological response is measured and averaged in order to detect oddball effects in response to the probes (CIT Protocol). It is assumed that the probes elicit an orienting response due to their deviant appearance as familiar and significant 19-21. In addition to orienting, there is evidence of an arousal inhibition effect that is applied by the subjects to conceal their orienting activity, and its measure is used for detecting deception 22. Typically, CIT measures physiological responses such as heart rate and skin conductance 19 , neural responses, primarily the P300 brain wave 23 , as well as eye movements, eye blinks, and pupil dilation 24-27. These measures typically require a serial repetitive presentation for averaging; as a result, false positives could occur due to an arbitrary orienting and to the observer's fatigue as well as biological noise, affecting the signal-to-noise ratio (SNR) as in the P300 BCI methods 28. This suggests that a possible tradeoff exists between accuracy and susceptibility to deception using CIT methods, as ways to increase the SNR such as longer exposures or more repetitions for averaging, could provide more opportunities for deception (e.g. 29).

Fixation-related saccadic inhibition in free viewing in response to stimulus saliency

“…Finally, we can consider predictions of the shared mechanism hypothesis that could be tested experimentally. Since for flashed stimuli, the microsaccade inhibition is generally related to the processing time of the flashed stimulus, e.g., with word 35 , sound 68 , 76 , and face 33 , 77 categorization, it is possible to generate and test similar conditions in natural vision; it involves moving the eyes over a static display from one stimulus to another. With large enough saccades, which prevent pre-saccadic peripheral identification, the saccadic inhibition or refractory period should depend primarily on the fixated stimulus; it is predicted to be similar to the flashed stimulus results.…”

Keep an eye on your belongings: Gaze dynamics toward familiar and unfamiliar objects.

“…The CIT effect is the differential response elicited by the familiar objects. Recent studies have shown promising detection efficiency using eye tracking measurements, even when participants actively tried to conceal their knowledge (Gamer & Pertzov, 2018; Lancry-Dayan et al, 2018; Millen & Hancock, 2019; Peth et al, 2013; Rosenzweig & Bonneh, 2020). In this framework, it is highly relevant to understand how gaze preference toward familiar and unfamiliar stimuli is influenced by the degree of familiarity, voluntary control and diverse types of stimuli.…”

Face Familiarity Revealed by Fixational Eye Movements and Fixation-Related Potentials in Free Viewing

“…Face familiarity is of a major interest in research on concealed memories; the Concealed Information Test (CIT) is used for testing the familiarity of suspects to specific people and objects (Rosenfeld, 2020). Our recent study found prolonged OMI at fixation for a masked familiar face (Rosenzweig & Bonneh, 2019), which allowed us to reliably detect identity in a concealed information test (Rosenzweig & Bonneh, 2020). Next, we will review in more detail the currently known oculomotor and the ERP measures of familiarity.…”