Andrea K. Webb

Effectiveness of Pupil Diameter in a Probable-Lie Comparison Question Test for Deception

Purpose. There were three objectives of this study: (1) To assess the possibility of using pupil diameter as an index of deception in the context of a comparison question polygraph test. (2) To determine if pupil diameter would make a significant contribution to an optimal multivariate classification equation in combination with the traditional predictor variables used in field polygraph practice. (3) We explored the possibility of replacing one or more of the traditional predictor variables with pupil diameter. Methods. We used a laboratory mock crime experiment with 24 participants, half of whom stole

Physiological reactivity to nonideographic virtual reality stimuli in veterans with and without PTSD

20 (US) from a secretarys purse. Participants were tested with a comparison question test modelled after standard field practice. Physiological measures were taken with laboratory quality instrumentation. Features were extracted from the physiological measures. Those features were subjected to a number of different statistical analyses. Results. Innocent participants showed larger increases in pupil diameter in response to probable-lie questions than to relevant questions. Guilty participants did not show differential responding to the question types. The additional of pupil diameter to a multivariate classification model approached, but did not reach significance. Subsequent analyses suggest that pupil diameter might be used to replace the traditional relative blood pressure measure. Conclusions. Pupil diameter was found to be a significant predictor variable for deception. Pupil diameter may be a possible replacement for the traditional relative blood pressure measure. Additional research to explore that possibility would seem to be warranted.

Eye Movements and Pupil Size Reveal Deception in Computer Administered Questionnaires

Post‐traumatic stress disorder (PTSD) currently is diagnosed via clinical interview in which subjective self reports of traumatic events and associated experiences are discussed with a mental health professional. The reliability and validity of diagnoses can be improved with the use of objective physiological measures.

Reduced emotional and cardiovascular reactivity to emotionally evocative stimuli in major depressive disorder

An oculomotor test is described that uses pupil diameter and eye movements during reading to detect deception. Forty participants read and responded to statements on a computerized questionnaire about their possible involvement in one of two mock crimes. Twenty guilty participants committed one of two mock crimes, and 20 innocent participants committed no crime. Guilty participants demonstrated speeded and accurate reading when they encountered statements about their crime and increases in pupil size. A discriminant function of oculomotor measures successfully discriminated between guilty and innocent participants and between the two groups of guilty participants. Results suggest that oculomotor tests may be of value for pre-employment and security screening applications.

Wearable sensors can assist in PTSD diagnosis

Major Depressive Disorder (MDD) is a highly debilitating mental health concern that affects a large number of adults in the United States. The emotional context insensitivity (ECI) hypothesis argues that individuals with MDD disengage from the environment to defend themselves from futile activity. In the current study, electrocardiogram and pupillometry were recorded from 50 participants (MDD n=25, never depressed control n=25) during the display of emotionally evocative images, sounds, and movie clips. Individuals with MDD reported reduced change in happiness to positively- and negatively-valenced images and sounds. Heart rate reactivity also was reduced in individuals with MDD when viewing images and watching movie clips. These results suggest that individuals with MDD may have some difficulty engaging with certain environmental stimuli.

Operationalizing Engagement with Multimedia as User Coherence with Context

Post-traumatic stress disorder (PTSD) currently is diagnosed via subjective reports of experiences related to the traumatic event. More objective measures are needed to assist clinicians in diagnosis. Physiological activity was recorded from 58 participants. Participants in the No Trauma/No PTSD group had no trauma exposure and no PTSD diagnosis. Trauma Exposed/No PTSD participants had experienced a traumatic event but did not have PTSD. PTSD participants had experienced a traumatic event and had PTSD. Baseline and emotionally evocative stimulus-related sensor data were collected. Features were extracted from each sensor stream and submitted to statistical analysis. Significant group differences were present during the viewing of two virtual reality videos. Features were submitted to discriminant function analysis to assess classification accuracy. Classification accuracy was between 89 and 92%. The results from this study suggest the utility of objective physiological measures obtained from wearable sensors in assisting with PTSD diagnosis.

Detection of Deception in Structured Interviews Using Sensors and Algorithms

Traditional approaches for assessing user engagement within multimedia environments rely on methods that are removed from the human computer interaction itself, such as surveys, interviews and baselined physiology. We propose a context coherence approach that operationalizes engagement as the amount of independent user variation that covaries in time with multimedia contextual events during unscripted interactions. This can address questions about the features of multimedia users are most engaged and how engaged users are without the need for prescribed interactions or baselining. We assessed the validity of this approach in a psychophysiological study. Forty participants played interactive video games. Intake and post-stimulus questionnaires collected subjective engagement reports that provided convergent and divergent validity criteria to evaluate our approach. Estimates of coherence between physiological variation and in-game contextual events predicted subjective engagement and added information beyond physiological metrics computed from baselines taken outside of the multimedia context. Our coherence metric accounted for task-dependent engagement, independent of predispositions; this was not true of a baselined physiological approach that was used for comparison. Our findings show compelling evidence that a context-sensitive approach to measuring engagement overcomes shortcomings of traditional methods by making best use of contextual information sampled from multimedia in time-series analyses.

User Abilities in Detecting Vibrotactile Signals on the Feet Under Varying Attention Loads

Draper Laboratory and MRAC have recently completed a comprehensive study to quantitatively evaluate deception detection performance under different interviewing styles. The interviews were performed while multiple physiological waveforms were collected from participants to determine how well automated algorithms can detect deception based upon changes in physiology. We report the results of a multi-factorial experiment with 77 human participants who were deceptive on specific topics during interviews conducted with one of two styles: a forcing style which relies on more coercive or confrontational techniques, or a fostering approach, which relies on open-ended interviewing and elements of a cognitive interview. The interviews were performed in a state-of-the-art facility where multiple sensors simultaneously collect synchronized physiological measurements, including electrodermal response, relative blood pressure, respiration, pupil diameter, and ECG. Features extracted from these waveforms during honest and deceptive intervals were then submitted to a hypothesis test to evaluate their statistical significance. A univariate statistical detection algorithm then assessed the ability to detect deception for different interview configurations. Our paper will explain the protocol and experimental design for this study. Our results will be in terms of statistical significances, effect sizes, and ROC curves and will identify how promising features performed in different interview scenarios.

Physiological Correlates of Emotional State

The future of human space exploration will involve extra-vehicular activities EVA on foreign planetary surfaces i.e. Mars, an activity that will have significantly different characteristics than the common exploration scenarios on Earth. The required use of a bulky, pressurized EVA suit perceptually disconnects human explorers from the hostile foreign environment, increasing the navigation workload and risk of collision associated with traversing through unfamiliar, rocky terrain. To assist the explorer in such tasks, multi-modal information presentation devices are being designed and evaluated. One application is to assist astronauts in ground obstacle avoidance via tactile channels of the feet. Before utilizing these signals as a form of information presentation, it is necessary to first characterize the tactile perception capabilities of the feet for selected vibration location and signal types, in particular during distracted attention states. The perception of tactile signals must be robust under various cognitive loads as the user will be involved in multiple tasks. The current study consisted of participants completing a vibrotactile detection study, with independent variables of attention state, vibration location and vibration signal type. Tactile cues were provided using haptic motor vibrations at six different locations on each foot for four different vibration levels High, Low, Increasing and Decreasing, resulting in 24 unique vibrations per foot. Each treatment was repeated six times per attention state and vibrations were presented randomly within a time window of 2---7i¾?s. After each trial, participants indicated the location and level of the vibration perceived. Accuracy of response was analyzed across conditions and results provide implications for the presentation of tactile information on the feet under varying attentioni¾?states.

Analysis of a wearable, multi-modal information presentation device for obstacle avoidance

This study examined the relationship between emotion and physiological measures of autonomic system response. Features of electrodermal, cardiac, respiratory, movement, and oculomotor response were measured from a population of normal subjects while they were presented standard acoustic and visual stimuli designed to evoke specific emotions. The subjects’ assessments of their emotional response to the stimuli (self-report) were also recorded. We present results of a preliminary analysis of the statistical relationship between the stimulus category, the physiological features and self-report. We found significant differences across stimulus categories, as well as across self-reported emotions, suggesting that a combination of features could be used to classify the emotional content of a discrete stimulus. We also examine the dependence of physiological signals on the mode of stimulus presentations.