650 research outputs found

    Master of Science

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    thesisThe present mock crime study investigated whether the accuracy of an ocular-motor deception test (ODT) that directly asks if the person committed illicit acts differs from the accuracy of an ODT that indirectly asks if the person provided false answers on a questionnaire about those illicit activities. Guilt, statement type, relevant issue, and completion of a pre-ODT questionnaire were manipulated in the present study to assess their effects on ocular-motor and behavioral measures of deception. Half the subjects were guilty of taking $20 from a secretary's wallet, and the other half were innocent. All subjects were told that some subjects took an exam from a professor's office, but in actuality, no one committed that crime. Three-fourths of the subjects completed a pre-ODT questionnaire that asked about their involvement in the crimes. Subjects answered 48 true/false items five times while their eye movements and pupil diameters were recorded. Half of the guilty and innocent subjects answered test items that directly asked if they committed the thefts. The remaining subjects were asked if they falsified information about the crimes on the pre-ODT questionnaire. Guilty subjects showed the largest pupil diameter while reading the cash items. For direct items, a discriminant function of four ocular-motor measures correctly classified 95% of innocent subjects and 83% of guilty subjects. For indirect items, the discriminant analysis of three ocular-motor measures correctly classified 79% of innocent subjects and 58% of guilty subjects. Results suggest that indirect test items are less effective than direct ones

    The dual pathway to information avoidance in information systems use

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    This article develops an explanatory model of information avoidance behavior from extant theory and examines its hypotheses using psychophysiological methods. It integrates existing but partially conflicting explanations into a coherent positivist model based on Coping Theory. The existence of two distinct but interlinked causal pathways to information avoidance will be outlined. Both pathways are cause by defects in the information quality. The first pathway is grounded on being threatened by the information’s inconsistency. The second pathway is based on being distressed by the information’s complexity. Due to the involvement of cognition as well as affect, the usefulness of traditional measurement methods alone is deemed to be limited. Thus, we will draw upon recent advances from NeuroIS research in order to integrate psychophysiological measures into an extended, triangulated measurement protocol. This article intends to contribute to this special issue in three ways. First, it shapes a theoretical model for studying information avoidance which has received little attention in IS research. Second, it exemplifies the derivation and instantiation of a NeuroIS measurement model and the selection of appropriate NeuroIS methods for scrutinizing the theoretical information avoidance model. Third, based on the evidence of an experiment, it provides guidelines for how to conduct eye-tracking, pupillometry, and facial electromyography measurements as well as how to subsequently derive meaning from the initial data collected

    The cost of space independence in P300-BCI spellers.

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    Background: Though non-invasive EEG-based Brain Computer Interfaces (BCI) have been researched extensively over the last two decades, most designs require control of spatial attention and/or gaze on the part of the user. Methods: In healthy adults, we compared the offline performance of a space-independent P300-based BCI for spelling words using Rapid Serial Visual Presentation (RSVP), to the well-known space-dependent Matrix P300 speller. Results: EEG classifiability with the RSVP speller was as good as with the Matrix speller. While the Matrix speller’s performance was significantly reliant on early, gaze-dependent Visual Evoked Potentials (VEPs), the RSVP speller depended only on the space-independent P300b. However, there was a cost to true spatial independence: the RSVP speller was less efficient in terms of spelling speed. Conclusions: The advantage of space independence in the RSVP speller was concomitant with a marked reduction in spelling efficiency. Nevertheless, with key improvements to the RSVP design, truly space-independent BCIs could approach efficiencies on par with the Matrix speller. With sufficiently high letter spelling rates fused with predictive language modelling, they would be viable for potential applications with patients unable to direct overt visual gaze or covert attentional focus

    Developing a methodology for manipulating spontaneous blinks.

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    While blinking is necessary for ocular protection and lubrication, people blink much more than is necessary for routine ocular maintenance. These extra, spontaneous blinks are extremely difficult to manipulate and thus, have remained somewhat of a mystery. In order to determine the effects of spontaneous blinks, a methodology to manipulate them naturally must be created. The aim of this study was to develop such methodology using videos of animated speakers displaying high and low blink rates, and determine whether this influenced participant blink rates. It was expected that watching videos of a speaker's face would manipulate blink rate. It was also expected that participants would imitate the speaker's blink timing and blink immediately after the speaker blinks, called blink entrainment. Participants watched four videos, two featuring an animated speaker with a high blink rate, and two featuring the same animated speaker with a low blink rate. In between the speaker videos, participants completed ten trials of several variations of a lexical decision task. The speaker videos provided instructions on how to complete each of these tasks. A Wilcoxon signed-rank test showed that the differences between participant blink rates across the high blink rate and the low blink rate were significant (Z = -3.16, p = .002). Participants blinked more frequently while watching the high blink rate videos than when watching the low blink rate videos. A Wilcoxon signed-rank test also showed a significant difference between entrainment blinks and non-entrainment blinks in the high blink rate condition (Z = -3.65, p = .001), and the low blink rate condition (Z = -2.21, p = .027). These results indicate that a standardized methodology for manipulating spontaneous blinks is possible. With the use of the animated speaker videos, spontaneous blinks can be manipulated

    The effects of cognitive load and lying types on deception cues

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    120 leaves : ill. ; 29 cm.Includes abstract and appendices.Includes bibliographical references (leaves 94-105).Over the last decade, inducing cognitive load has been introduced as a possible lie detection technique (Vrij, et al., 2006). Evidence suggests that lying is a cognitively taxing task; therefore, increasing a deceiver’s cognitive demands should make lying even more difficult, and true deception cues should become apparent. The present study investigated various behavioural cues that occurred between individuals who lied by omission or falsification. Cognitive load was used to amplify deception cues within subjects on half of the interview questions. It was predicted that there would be differences between cues based on deception type. The findings in the present study have revealed a main effect of cognitive load and a main effect of lying type. There was no interaction effect between cognitive load and falsification. The individual deception cues that were responsible for the variance are identified and implications for deception detection research and law enforcement are discussed

    Psychophysiological indices of recognition memory

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    It has recently been found that during recognition memory tests participants’ pupils dilate more when they view old items compared to novel items. This thesis sought to replicate this novel ‘‘Pupil Old/New Effect’’ (PONE) and to determine its relationship to implicit and explicit mnemonic processes, the veracity of participants’ responses, and the analogous Event-Related Potential (ERP) old/new effect. Across 9 experiments, pupil-size was measured with a video-based eye-tracker during a variety of recognition tasks, and, in the case of Experiment 8, with concurrent Electroencephalography (EEG). The main findings of this thesis are that: - the PONE occurs in a standard explicit test of recognition memory but not in “implicit” tests of either perceptual fluency or artificial grammar learning; - the PONE is present even when participants are asked to give false behavioural answers in a malingering task, or are asked not to respond at all; - the PONE is present when attention is divided both at learning and during recognition; - the PONE is accompanied by a posterior ERP old/new effect; - the PONE does not occur when participants are asked to read previously encountered words without making a recognition decision; - the PONE does not occur if participants preload an “old/new” response; - the PONE is not enhanced by repetition during learning. These findings are discussed in the context of current models of recognition memory and other psychophysiological indices of mnemonic processes. It is argued that together these findings suggest that the increase in pupil-size which occurs when participants encounter previously studied items is not under conscious control and may reflect primarily recollective processes associated with recognition memory

    Eye tracking and avatar-mediated communication in immersive collaborative virtual environments

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    The research presented in this thesis concerns the use of eye tracking to both enhance and understand avatar-mediated communication (AMC) performed by users of immersive collaborative virtual environment (ICVE) systems. AMC, in which users are embodied by graphical humanoids within a shared virtual environment (VE), is rapidly emerging as a prevalent and popular form of remote interaction. However, compared with video-mediated communication (VMC), which transmits interactants’ actual appearance and behaviour, AMC fails to capture, transmit, and display many channels of nonverbal communication (NVC). This is a significant hindrance to the medium’s ability to support rich interpersonal telecommunication. In particular, oculesics (the communicative properties of the eyes), including gaze, blinking, and pupil dilation, are central nonverbal cues during unmediated social interaction. This research explores the interactive and analytical application of eye tracking to drive the oculesic animation of avatars during real-time communication, and as the primary method of experimental data collection and analysis, respectively. Three distinct but interrelated questions are addressed. First, the thesis considers the degree to which quality of communication may be improved through the use of eye tracking, to increase the nonverbal, oculesic, information transmitted during AMC. Second, the research asks whether users engaged in AMC behave and respond in a socially realistic manner in comparison with VMC. Finally, the degree to which behavioural simulations of oculesics can both enhance the realism of virtual humanoids, and complement tracked behaviour in AMC, is considered. These research questions were investigated over a series of telecommunication experiments investigating scenarios common to computer supported cooperative work (CSCW), and a further series of experiments investigating behavioural modelling for virtual humanoids. The first, exploratory, telecommunication experiment compared AMC with VMC in a three-party conversational scenario. Results indicated that users employ gaze similarly when faced with avatar and video representations of fellow interactants, and demonstrated how interaction is influenced by the technical characteristics and limitations of a medium. The second telecommunication experiment investigated the impact of varying methods of avatar gaze control on quality of communication during object-focused multiparty AMC. The main finding of the experiment was that quality of communication is reduced when avatars demonstrate misleading gaze behaviour. The final telecommunication study investigated truthful and deceptive dyadic interaction in AMC and VMC over two closely-related experiments. Results from the first experiment indicated that users demonstrate similar oculesic behaviour and response in both AMC and VMC, but that psychological arousal is greater following video-based interaction. Results from the second experiment found that the use of eye tracking to drive the oculesic behaviour of avatars during AMC increased the richness of NVC to the extent that more accurate estimation of embodied users’ states of veracity was enabled. Rather than directly investigating AMC, the second series of experiments addressed behavioural modelling of oculesics for virtual humanoids. Results from the these experiments indicated that oculesic characteristics are highly influential to the perceived realism of virtual humanoids, and that behavioural models are able to complement the use of eye tracking in AMC. The research presented in this thesis explores AMC and eye tracking over a range of collaborative and perceptual studies. The overall conclusion is that eye tracking is able to enhance AMC towards a richer medium for interpersonal telecommunication, and that users’ behaviour in AMC is no less socially ‘real’ than that demonstrated in VMC. However, there are distinct differences between the two communication mediums, and the importance of matching the characteristics of a planned communication with those of the medium itself is critical
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