@phdthesis{Zuern2015, author = {Z{\"u}rn, Michael}, title = {The Dual Nature of Utility - Categorical and Comparative Evaluations in Economic Decisions}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120141}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Utility is perhaps the most central concept in modern economic theorizing. However, the behaviorist reduction to Revealed Preference not only removed the psychological content of utility but experimental investigations also exposed numerous anomalies in this theory. This program of research focused on the psychological processes by which utility judgments are generated. For this purpose, the standard assumption of a homogeneous concept is substituted by the Utilitarian Duality Hypothesis. In particular, judgments concerning categorical utility (uCat) infer an object's category based on its attributes which may subsequently allow the transfer of evaluative information like feelings or attitudes. In contrast, comparative utility (uCom) depends on the distance to a reference value on a specific dimension of comparison. Importantly, dimensions of comparison are manifold and context dependent. In a series of experiments, we show that the resulting Dual Utility Model is able to explain several known anomalies in a parsimonious fashion. Moreover, we identify central factors determining the relative weight assigned to both utility components. Finally, we discuss the implications of the Utilitarian Duality for both, the experimental practice in economics as well as the consequences for economic theorizing. In sum, we propose that the Dual Utility Model can serve as an integrative framework for both the rational model and its anomalies.}, subject = {Nutzen}, language = {en} } @phdthesis{Wiemer2015, author = {Wiemer, Julian}, title = {Maintaining factors of fear-relevant illusory correlations}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-116960}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Biased cognitive processes are very likely involved in the maintenance of fears and anxiety. One of such cognitive processes is the perceived relationship between fear-relevant stimuli and aversive consequences. If this relationship is perceived although objective contingencies have been random, it is called an (a posteriori) illusory correlation. If this relationship is overestimated before objective contingencies are experienced, it is called an (a priori) expectancy bias. Previous investigations showed that fear-relevant illusory correlations exist, but very few is known about how and why this cognitive bias develops. In the present dissertation thesis, a model is proposed based on a review of the literature on fear-relevant illusory correlations. This model describes how psychological factors might have an influence on fear and illusory correlations. Several critical implications of the model were tested in four experiments. Experiment 1 tested the hypothesis that people do not only overestimate the proportion of aversive consequences (startle sounds) following emotionally negative stimuli (pictures of mutilations) relative to neutral stimuli (pictures of household objects), but also following highly arousing positive stimuli (pictures of erotic scenes), because arousal might be an important determinant of illusory correlations. The result was a significant expectancy bias for negative stimuli and a much smaller expectancy bias for positive stimuli. Unexpectedly, expectancy bias was restricted to women. An a posteriori illusory correlation was not found overall, but only in those participants who perceived the aversive consequences following negative stimuli as particularly aversive. Experiment 2 tested the same hypothesis as experiment 1 using a paradigm that evoked distinct basic emotions (pictures inducing fear, anger, disgust or happiness). Only negative emotions resulted in illusory correlations with aversive outcomes (startle sounds), especially the emotions of fear and disgust. As in experiment 1, the extent of these illusory correlations was correlated with the perceived aversiveness of aversive outcomes. Moreover, only women overestimated the proportion of aversive outcomes during pictures that evoked fear, anger or disgust. Experiment 3 used functional Magnetic Resonance Imaging (fMRI) to measure biased brain activity in female spider phobics during an illusory correlation paradigm. Both spider phobics and healthy controls expected more aversive outcomes (painful electrical shocks) following pictures of spiders than following neutral control stimuli (pictures of mushrooms). Spider phobics but not healthy controls overestimated the proportion of aversive outcomes following pictures of spiders in a trial-by-trial memory task. This a posteriori illusory correlation was correlated with enhanced shock aversiveness and activity in primary sensory-motor cortex in phobic participants. Moreover, spider phobics' brain activity in the left dorsolateral prefrontal cortex was elevated in response to spider images. This activity also predicted the extent of the illusory correlation, which supports the theory that executive and attentional resources play an important role in the maintenance of illusory correlations. Experiment 4 tested the hypothesis that the enhanced aversiveness of some outcomes would be sufficient to causally induce an illusory correlation. Neutral images (colored geometric figures) were paired with differently aversive outcomes (three startle sounds varying in intensity). Participants developed an illusory correlation between those images, which predicted the most aversive sound and this sound, which means that this association was overestimated relative to the other associations. The extent of the illusory correlation was positively correlated with participants' self-reported anxiety. The results imply that the previously found relationship between illusory correlations and outcome aversiveness might reflect a causal impact of outcome aversiveness or salience on illusory correlations. In sum, the conducted experiments indicate that illusory correlations between fear-relevant stimuli and aversive consequences might persist - among other factors - because of an enhanced aversiveness or salience of aversive consequences following feared stimuli. This assumption is based on correlational findings, a neural measure of outcome perception and a causal influence of outcome aversiveness on illusory correlations. Implications of these findings were integrated into a model of fear-relevant illusory correlations and potential implications are discussed. Future investigations should further elucidate the role of executive functions and gender effects. Moreover, the trial-by-trial assessment of illusory correlations is recommended to increase reliability of the concept. From a clinical perspective, the down-regulation of aversive experiences and the allocation of attention to non-aversive experiences might help to cure anxiety and cognitive bias.}, subject = {Verzerrte Kognition}, language = {en} } @phdthesis{Sollfrank2015, author = {Sollfrank, Teresa}, title = {Feedback efficiency and training effects during alpha band modulation over the sensorimotor cortex}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131769}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Neural oscillations can be measured by electroencephalography (EEG) and these oscillations can be characterized by their frequency, amplitude and phase. The mechanistic properties of neural oscillations and their synchronization are able to explain various aspects of many cognitive functions such as motor control, memory, attention, information transfer across brain regions, segmentation of the sensory input and perception (Arnal and Giraud, 2012). The alpha band frequency is the dominant oscillation in the human brain. This oscillatory activity is found in the scalp EEG at frequencies around 8-13 Hz in all healthy adults (Makeig et al., 2002) and considerable interest has been generated in exploring EEG alpha oscillations with regard to their role in cognitive (Klimesch et al., 1993; Hanselmayr et al., 2005), sensorimotor (Birbaumer, 2006; Sauseng et al., 2009) and physiological (Lehmann, 1971; Niedermeyer, 1997; Kiyatkin, 2010) aspects of human life. The ability to voluntarily regulate the alpha amplitude can be learned with neurofeedback training and offers the possibility to control a brain-computer interface (BCI), a muscle independent interaction channel. BCI research is predominantly focused on the signal processing, the classification and the algorithms necessary to translate brain signals into control commands than on the person interacting with the technical system. The end-user must be properly trained to be able to successfully use the BCI and factors such as task instructions, training, and especially feedback can therefore play an important role in learning to control a BCI (Neumann and K{\"u}bler, 2003; Pfurtscheller et al., 2006, 2007; Allison and Neuper, 2010; Friedrich et al., 2012; Kaufmann et al., 2013; Lotte et al., 2013). The main purpose of this thesis was to investigate how end-users can efficiently be trained to perform alpha band modulation recorded over their sensorimotor cortex. The herein presented work comprises three studies with healthy participants and participants with schizophrenia focusing on the effects of feedback and training time on cortical activation patterns and performance. In the first study, the application of a realistic visual feedback to support end-users in developing a concrete feeling of kinesthetic motor imagery was tested in 2D and 3D visualization modality during a single training session. Participants were able to elicit the typical event-related desynchronisation responses over sensorimotor cortex in both conditions but the most significant decrease in the alpha band power was obtained following the three-dimensional realistic visualization. The second study strengthen the hypothesis that an enriched visual feedback with information about the quality of the input signal supports an easier approach for motor imagery based BCI control and can help to enhance performance. Significantly better performance levels were measurable during five online training sessions in the groups with enriched feedback as compared to a conventional simple visual feedback group, without significant differences in performance between the unimodal (visual) and multimodal (auditory-visual) feedback modality. Furthermore, the last study, in which people with schizophrenia participated in multiple sessions with simple feedback, demonstrated that these patients can learn to voluntarily regulate their alpha band. Compared to the healthy group they required longer training times and could not achieve performance levels as high as the control group. Nonetheless, alpha neurofeedback training lead to a constant increase of the alpha resting power across all 20 training session. To date only little is known about the effects of feedback and training time on BCI performance and cortical activation patterns. The presented work contributes to the evidence that healthy individuals can benefit from enriched feedback: A realistic presentation can support participants in getting a concrete feeling of motor imagery and enriched feedback, which instructs participants about the quality of their input signal can give support while learning to control the BCI. This thesis demonstrates that people with schizophrenia can learn to gain control of their alpha oscillations recorded over the sensorimotor cortex when participating in sufficient training sessions. In conclusion, this thesis improved current motor imagery BCI feedback protocols and enhanced our understanding of the interplay between feedback and BCI performance.}, subject = {Neurofeedback}, language = {en} } @phdthesis{Rittger2015, author = {Rittger, Lena}, title = {Driving Behaviour and Driver Assistance at Traffic Light Intersections}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117646}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {The increasing importance of environmental friendly and efficient transportation guides the interest of researchers and car manufacturers towards the development of technologies that support an efficient driving style. This thesis presents the development of a traffic light assistance system with the focus on human factors. The system aims on supporting drivers in approaching traffic light intersections efficiently. In three driving simulator studies, the content related research covered the investigation of the unassisted driving task, the influence of the system on the driver's perception of the interaction with other road users and the information strategy of the human machine interface. When the traffic light phase changes or when visibility is limited, drivers prepare driving behaviour that is not appropriate for the traffic light phase at arrival at the intersection. These situations offer the greatest potential for the assistance system. The traffic light assistant is able to change driving behaviour. However, the expectation of other road user's emotional reactions influences driver compliance. In situations in which drivers expected to bother others with their driving behaviour, compliance to the traffic light assistant was low. Further, the deviations of driver behaviour from the target strategy of the traffic light assistant are lowest when the HMI includes the two information units target speed and action recommendations. Traffic light phase information in the HMI is a subjectively important information for drivers. The results point towards the presentation of all three information units. The method related research covered the development of a method for measuring drivers' information demand for dynamic stimuli. While driving, specific stimuli are action relevant for drivers, i.e. they need to be processed in order to decide on the appropriate driving behaviour. Eye tracking has been the standard method for measuring information demand while driving. The novel MARS (Masking Action Relevant Stimuli) method measures information demand by masking the dynamic action relevant stimulus in the driving environment or in the vehicle. To unmask the stimulus for a fixed interval, drivers press a button at the steering wheel. In the present thesis, two driving simulator studies evaluated the MARS method. They included measuring information demand for the traffic light phasing and the in-vehicle display of the traffic light assistant. The analyses demonstrate that variations in the experimental conditions influence the information demand measured with the MARS method qualitatively similar to the influences on fixations measured by eye tracking. Due to its simple application, the MARS method represents a promising tool for transportation research.}, subject = {Fahrerassistenzsystem}, language = {en} } @phdthesis{Naujoks2015, author = {Naujoks, Frederik}, title = {Fr{\"u}hzeitige Fahrerinformationen zur Konfliktvermeidung bei urbanen Verkehrskonflikten - Gestaltung und Absicherung}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117180}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Die meisten Unf{\"a}lle mit Personenschaden in der Bundesrepublik Deutschland sind infolge urbaner Verkehrskonflikte zu verzeichnen. Die Mehrzahl dieser Unf{\"a}lle findet in Kreuzungssituationen statt (sog. Kreuzen-, Einbiege- und Abbiege-Unf{\"a}lle). Heutige Assistenzsysteme zur Kollisionsvermeidung oder -abschw{\"a}chung stoßen in diesen Situationen aufgrund der durch bordeigene Fahrzeugsensorik eingeschr{\"a}nkten M{\"o}glichkeiten zur Erfassung der Verkehrsumgebung an ihre Grenzen. Diese Einschr{\"a}nkungen ergeben sich beispielsweise durch Sichtverdeckungen (z.B. durch parkende Fahrzeuge oder H{\"a}userreihen, welche die Sicht in Kreuzungsarme verdecken) oder die begrenzte Erfassungsg{\"u}te verletzlicher Verkehrsteilnehmer (Fußg{\"a}nger, Radfahrer oder Motorradfahrer). Zuk{\"u}nftige kooperative Kommunikationstechnologien, basierend auf Fahrzeug-Fahrzeug- und Fahrzeug-Infrastruktur-Kommunikation, erm{\"o}glichen es, dem Fahrer auch in komplexen urbanen Konfliktsituationen fr{\"u}hzeitig Informationen {\"u}ber potentielle Gefahrensituationen zu {\"u}bermitteln. Gleichwohl liegen Konzepte zur Ausgestaltung einer solchen Fahrerunterst{\"u}tzung, die den F{\"a}higkeiten und Bed{\"u}rfnissen des Fahrers entsprechen, bislang nur vereinzelt vor. In dieser Arbeit wird deshalb ein neuartiges Konzept zur fr{\"u}hzeitigen Fahrerunterst{\"u}tzung entwickelt und in einer im Fahrsimulator durchgef{\"u}hrten Studienreihe empirisch evaluiert. Ziel ist es, dem Fahrer im Gegensatz zu dringlichen Kollisionswarnungen, wie sie heutzutage beispielsweise im Kontext von Notbremsassistenten verwendet werden, fr{\"u}hzeitig auf drohende Verkehrskonflikte hinzuweisen. Um die Zuverl{\"a}ssigkeit dieser Unterst{\"u}tzung zu erh{\"o}hen, soll der Fahrer (1.) so fr{\"u}h wie n{\"o}tig aber so sp{\"a}t wie m{\"o}glich, (2.) so spezifisch wie n{\"o}tig und (3.) so dringlich wie n{\"o}tig informiert werden. Diese drei zentralen Gestaltungskriterien (Zeitpunkt, Spezifit{\"a}t und Dringlichkeit) wurden in meiner Arbeit in umfassenden Probandenstudien empirisch untersucht, wobei die zu erwartende Unzuverl{\"a}ssigkeit der maschinellen Situationsanalyse und -pr{\"a}diktion expliziter Bestandteil des Studiendesigns war. Folgende Gestaltungsempfehlungen k{\"o}nnen, basierend auf den Studienergebnissen, gegeben werden: Zeitpunkt: Die Fahrerinformationen sollten eine bis zwei Sekunden vor dem letztm{\"o}glichen Warnzeitpunkt (t0+1s/2s) pr{\"a}sentiert werden. Noch fr{\"u}hzeitigere Fahrerinformationen f{\"u}hrten zu keiner weiteren Wirksamkeitssteigerung. Fahrerinformationen zum letztm{\"o}glichen Warnzeitpunkt (t0) hatten keinen positiven Einfluss auf das Fahrverhalten. Spezifit{\"a}t: Die Fahrerinformationen sollten eine Anzeige der Richtung, aus welcher der Konflikt droht (sog. richtungsspezifische Anzeige), beinhalten. Unspezifische Anzeigen (bloße Anzeige, dass ein Konflikt droht) f{\"u}hrten zwar zu vergleichbaren Verhaltenseffekten wie spezifische Anzeigen. Die Anzeige der Konfliktrichtung steigerte jedoch die wahrgenommene N{\"u}tzlichkeit der Fahrerunterst{\"u}tzung. Falls mit der Ausgabe fehlerhafter Richtungsanzeigen zu rechnen ist, wird dennoch eine unspezifische Anzeigestrategie empfohlen, da fehlerhafte Richtungsanzeigen eine Einschr{\"a}nkung der subjektiven N{\"u}tzlichkeit zur Folge hatten. Auch die Anzeige der Art des Konfliktpartners f{\"u}hrte zu einer h{\"o}heren subjektiven N{\"u}tzlichkeit, jedoch berichteten die Fahrer gleichzeitig von einer erh{\"o}hten Ablenkungswirkung dieser Anzeigen. Dringlichkeit: Es sollte ein rein visuelles Anzeigekonzept verwendet werden. Zwar f{\"u}hrten dringlichere, visuell-auditive Anzeigen zu einer schnelleren Bremsreaktion als rein visuelle Anzeigen. In Anbetracht der Fr{\"u}hzeitigkeit der Fahrerinformationen war dies zum einen jedoch nicht entscheidend f{\"u}r deren Wirksamkeit. Zum anderen wirkten sich falsche Alarme gerade bei visuell-auditiven Fahrerinformationen negativ auf Bremsreaktion und Wirksamkeit aus.}, language = {de} } @phdthesis{Kaethner2015, author = {K{\"a}thner, Ivo R. J.}, title = {Auditory and visual brain-computer interfaces as communication aids for persons with severe paralysis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-135477}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Brain-computer interfaces (BCIs) could provide a muscle-independent communication channel to persons with severe paralysis by translating brain activity into device commands. As a means of communication, in particular BCIs based on event-related potentials (ERPs) as control signal have been researched. Most of these BCIs rely on visual stimulation and have been investigated with healthy participants in controlled laboratory environments. In proof-of-principle studies targeted end users gained control over BCI systems; however, these systems are not yet established as an assistive technology for persons who would most benefit from them. The main aim of this thesis is to advance the usability of ERP-BCIs for target users. To this end, five studies with BCIs have been conducted that enabled users to communicate by focusing their attention on external stimuli. Two studies were conducted in order to demonstrate the advantages and to further improve the practical application of visual BCIs. In the first study, mental workload was experimentally manipulated during prolonged BCI operation. The study showed the robustness of the visual ERP-BCI since users maintained a satisfactory level of control despite constant distraction in the form of background noise. Moreover, neurophysiological markers that could potentially serve as indicators of high mental workload or fatigue were revealed. This is a first step towards future applications in which the BCI could adapt to the mental state of the user (e.g. pauses if high mental workload is detected to prevent false selections). In the second study, a head-mounted display (HMD), which assures that stimuli are presented in the field of view of the user, was evaluated. High accuracies and information transfer rates, similar to a conventional display, were achieved by healthy participants during a spelling task. Furthermore, a person in the locked-in state (LIS) gained control over the BCI using the HMD. The HMD might be particularly suited for initial communication attempts with persons in the LIS in situations, where mounting a conventional monitor is difficult or not feasible. Visual ERP-BCIs could prove valuable for persons with residual control over eye muscles and sufficient vision. However, since a substantial number of target users have limited control over eye movements and/or visual impairments, BCIs based on non-visual modalities are required. Therefore, a main aspect of this thesis was to improve an auditory paradigm that should enable motor impaired users to spell by focusing attention on different tones. The two conducted studies revealed that healthy participants were able to achieve high spelling performance with the BCI already in the first session and stress the importance of the choice of the stimulus material. The employed natural tones resulted in an increase in performance compared to a previous study that used artificial tones as stimuli. Furthermore, three out of five users with a varying degree of motor impairments could gain control over the system within the five conducted sessions. Their performance increased significantly from the first to the fifth session - an effect not previously observed for visual ERP-BCIs. Hence, training is particularly important when testing auditory multiclass BCIs with potential users. A prerequisite for user satisfaction is that the BCI technology matches user requirements. In this context, it is important to compare BCIs with already established assistive technology. Thus, the fifth study of this dissertation evaluated gaze dependent methods (EOG, eye tracking) as possible control signals for assistive technology and a binary auditory BCI with a person in the locked-in state. The study participant gained control over all tested systems and rated the ease of use of the BCI as the highest among the tested alternatives, but also rated it as the most tiring due to the high amount of attention that was needed for a simple selection. Further efforts are necessary to simplify operation of the BCI. The involvement of end users in all steps of the design and development process of BCIs will increase the likelihood that they can eventually be used as assistive technology in daily life. The work presented in this thesis is a substantial contribution towards the goal of re-enabling communication to users who cannot rely on motor activity to convey their thoughts.}, subject = {Gehirn-Computer Schnittstelle}, language = {en} } @phdthesis{Kastner2015, author = {Kastner, Anna Katharina}, title = {Attention mechanisms in contextual anxiety and cued fear and their influence on processing of social cues}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123747}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Anxiety is an affective state characterized by a sustained, long-lasting defensive response, induced by unpredictable, diffuse threat. In comparison, fear is a phasic response to predictable threat. Fear can be experimentally modeled with the help of cue conditioning. Context conditioning, in which the context serves as the best predictor of a threat due to the absence of any conditioned cues, is seen as an operationalization of sustained anxiety. This thesis used a differential context conditioning paradigm to examine sustained attention processes in a threat context compared to a safety context for the first time. In three studies, the attention mechanisms during the processing of contextual anxiety were examined by measuring heart rate responses and steady-state-visually evoked potentials (ssVEPs). An additional focus was set on the processing of social cues (i.e. faces) and the influence of contextual information on these cues. In a last step, the correlates of sustained anxiety were compared to evoked responses by phasic fear, which was realized in a previously established paradigm combining predictable and unpredictable threat. In the first study, a contextual stimulus was associated with an aversive loud noise, while a second context remained unpaired. This conditioning paradigm created an anxiety context (CTX+) and a safety context (CTX-). After acquisition, a social agent vs. an object was presented as a distractor in both contexts. Heart rate and cortical responses, with ssVEPs by using frequency tagging, to the contexts and the distractors were assessed. Results revealed enhanced ssVEP amplitudes for the CTX+ compared to the CTX- during acquisition and during presentation of distractor stimuli. Additionally, the heart rate was accelerated in the acquisition phase, followed by a heart rate deceleration as a psychophysiological marker of contextual anxiety. Study 2 used the same context conditioning paradigm as Study 1. In contrast to the first study, persons with different emotional facial expressions were presented in the anxiety and safety contexts in order to compare the differential processing of these cues within periods of threat and safety. A similar anxiety response was found in the second study, although only participants who Abstract VIII were aware of the contingency between contexts and aversive event showed a sensory amplification of the threat context, indicated by heart rate response and ssVEP activation. All faces irrespective of their emotional expression received increased attentional resources when presented within the anxiety context, which suggests a general hypervigilance in anxiety contexts. In the third study, the differentiation of predictable and unpredictable threat as an operationalization of fear and anxiety was examined on a cortical and physiological level. In the predictable condition, a social cue was paired with an aversive event, while in the unpredictable condition the aversive event remained unpaired with the respective cue. A fear response to the predictable cue was found, indicated by increased oscillatory response and accelerated heart rate. Both predictable and unpredictable threat yielded increased ssVEP amplitudes evoked by the context stimuli, while the response in the unpredictable context showed longer-lasting ssVEP activation to the threat context. To sum up, all three studies endorsed anxiety as a long-lasting defensive response. Due to the unpredictability of the aversive events, the individuals reacted with hypervigilance in the anxiety context, reflected in a facilitated processing of sensory information and an orienting response. This hypervigilance had an impact on the processing of novel cues, which appeared in the anxiety context. Considering the compared stimuli categories, the stimuli perceived in a state of anxiety received increased attentional resources, irrespective of the emotional arousal conveyed by the facial expression. Both predictable and unpredictable threat elicited sensory amplification of the contexts, while the response in the unpredictable context showed longer-lasting sensory facilitation of the threat context.}, subject = {Angst}, language = {en} } @phdthesis{Holz2015, author = {Holz, Elisa Mira}, title = {Systematic evaluation of non-invasive brain-computer interfaces as assistive devices for persons with severe motor impairment based on a user-centred approach - in controlled settings and independent use}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126334}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Brain-computer interfaces (BCIs) are devices that translate signals from the brain into control commands for applications. Within the last twenty years, BCI applications have been developed for communication, environmental control, entertainment, and substitution of motor functions. Since BCIs provide muscle independent communication and control of the environment by circumventing motor pathways, they are considered as assistive technologies for persons with neurological and neurodegenerative diseases leading to motor paralysis, such as amyotrophic lateral sclerosis (ALS), muscular dystrophy, spinal muscular atrophy and stroke (K{\"u}bler, Kotchoubey, Kaiser, Wolpaw, \& Birbaumer, 2001). Although most researcher mention persons with severe motor impairment as target group for their BCI systems, most studies include healthy participants and studies including potential BCI end-users are sparse. Thus, there is a substantial lack of studies that investigate whether results obtained in healthy participants can be transferred to patients with neurodegenerative diseases. This clearly shows that BCI research faces a translational gap between intense BCI research and bringing BCI applications to end-users outside the lab (K{\"u}bler, Mattia, Rupp, \& Tangermann, 2013). Translational studies are needed that investigate whether BCIs can be successfully used by severely disabled end-users and whether those end-users would accept BCIs as assistive devices. Another obvious discrepancy exists between a plethora of short-term studies and a sparse number of long-term studies. BCI research thus also faces a reliability gap (K{\"u}bler, Mattia, et al., 2013). Most studies present only one BCI session, however the few studies that include several testing sessions indicate high inter- and intra-individual variance in the end-users' performance due to non-stationarity of signals. Long-term studies, however, are needed to demonstrate whether a BCI can be reliably used as assistive device over a longer period of time in the daily-life of a person. Therefore there is also a great need for reliability studies. The purpose of the present thesis was to address these research gaps and to bring BCIs closer to end-users in need, especially into their daily-lives, following a user-centred design (UCD). The UCD was suggested as theoretical framework for bringing BCIs to end-users by K{\"u}bler and colleagues (K{\"u}bler et al., 2014; Zickler et al., 2011). This approach aims at the close and iterative interaction between BCI developers and end-users with the final goal to develop BCI systems that are accepted as assistive devices by end-users. The UCD focuses on usability, that is, how well a BCI technology matches the purpose and meets the needs and requirements of the targeted end-users and was standardized with the ISO 9241-210. Within the UCD framework, usability of a device can be defined with regard to its effectiveness, efficiency and satisfaction. These aspects were operationalized by K{\"u}bler and colleagues to evaluate BCI-controlled applications. As suggested by Vaughan and colleagues, the number of BCI sessions, the total usage duration and the impact of the BCI on the life of the person can be considered as indicators of usefulness of the BCI in long-term daily-life use (Vaughan, Sellers, \& Wolpaw, 2012). These definitions and metrics for usability and usefulness were applied for evaluating BCI applications as assistive devices in controlled settings and independent use. Three different BCI applications were tested and evaluated by in total N=10 end-users: In study 1 a motor-imagery (MI) based BCI for gaming was tested by four end-users with severe motor impairment. In study 2, a hybrid P300 event-related (ERP) based BCI for communication was tested by four severely motor restricted end-users with severe motor impairment. Study 1 and 2 are short-term studies conducted in a controlled-setting. In study 3 a P300-ERP BCI for creative expression was installed for long-term independent use at the homes of two end-users in the locked-in state. Both end-users are artists who had gradually lost the ability to paint after being diagnosed with ALS. Results reveal that BCI controlled devices are accepted as assistive devices. Main obstacles for daily-life use were the not very aesthetic design of the EEG-cap and electrodes (cap is eye-catching and looks medical), low comfort (cables disturb, immobility, electrodes press against head if lying on a head cushion), complicated and time-consuming adjustment, low efficiency and low effectiveness, and not very high reliability (many influencing factors). While effectiveness and efficiency in the MI based BCI were lower compared to applications using the P300-ERP as input channel, the MI controlled gaming application was nevertheless better accepted by the end-users and end-users would rather like to use it compared to the communication applications. Thus, malfunctioning and errors, low speed, and the EEG cap are rather tolerated in gaming applications, compared to communication devices. Since communication is essential for daily-life, it has to be fast and reliable. BCIs for communication, at the current state of the art, are not considered competitive with other assistive devices, if other devices, such as eye-gaze, are still an option. However BCIs might be an option when controlling an application for entertainment in daily-life, if communication is still available. Results demonstrate that BCI is adopted in daily-life if it matches the end-users needs and requirements. Brain Painting serves as best representative, as it matches the artists' need for creative expression. Caveats such as uncomfortable cap, dependence on others for set-up, and experienced low control are tolerated and do not prevent BCI use on a daily basis. Also end-users in real need of means for communication, such as persons in the locked-in state with unreliable eye-movement or no means for independent communication, do accept obstacles of the BCI, as it is the last or only solution to communicate or control devices. Thus, these aspects are "no real obstacles" but rather "challenges" that do not prevent end-users to use the BCI in their daily-lives. For instance, one end-user, who uses a BCI in her daily-life, stated: "I don't care about aesthetic design of EEG cap and electrodes nor amplifier". Thus, the question is not which system is superior to the other, but which system is best for an individual user with specific symptoms, needs, requirements, existing assistive solutions, support by caregivers/family etc.; it is thereby a question of indication. These factors seem to be better "predictors" for adoption of a BCI in daily-life, than common usability criterions such as effectiveness or efficiency. The face valid measures of daily-life demonstrate that BCI-controlled applications can be used in daily-life for more than 3 years, with high satisfaction for the end-users, without experts being present and despite a decrease in the amplitude of the P300 signal. Brain Painting re-enabled both artists to be creatively active in their home environment and thus improved their feelings of happiness, usefulness, self-esteem, well-being, and consequently quality of life and supports social inclusion. This thesis suggests that BCIs are valuable tools for people in the locked-in state.}, subject = {Gehirn-Computer-Schnittstelle}, language = {en} } @phdthesis{Erlbeck2015, author = {Erlbeck, Helena}, title = {The event-related potentials Mismatch Negativity, P300, and N400: Effects of attentional modulation and application in patients with disorders of consciousness}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121041}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {The present work comprises four studies dealing with the investigation of the auditory event-related potentials (ERP) Mismatch Negativity (MMN), P300, and N400 under different attentional instructions, and with their application in patients with disorders of consciousness (DOC) to assess residual cognitive functioning. In guided interviews (study 1), practitioners working with DOC patients stated their general interest in and an objective need for the complementation of current diagnostic procedures by reliable and valid ERP-based methods. Subsequently, in study 2, simple oddball and semantic paradigms were applied to 19 behaviorally non-responsive DOC patients revealing the presence of at least one ERP in eight patients investigated. In the third and fourth study, specific attentional effects on ERPs were investigated in healthy participants to define optimal instructions and stimulus parameters. In study 3, MMN and N400 amplitudes were assessed in 18 participants, and in study 4, MMN and P300 amplitudes were assessed in 32 participants. Both studies included an ignore task (attention on simultaneous visual stimuli), a passive task, and a focused task and revealed distinct attentional effects on P300 and N400 with largest amplitudes in the focused task, smaller ones in the passive task and no ERP in the ignore task. An MMN was elicited in all tasks, but still, amplitudes differed as a function of task. In addition, study 4 included oddball paradigms comprising several deviants in different dimensions. Higher amplitudes were found in this multifeature paradigm compared to traditional oddball paradigms and larger amplitudes were elicited by deviants highly different from standards. It is concluded that ERPs represent a promising tool to complement clinical assessment of DOC patients. Application of ERP paradigms should include focused instructions, especially when using semantic material. Furthermore, multifeature paradigms have been proven especially useful eliciting large amplitudes and allowing for the investigation of several dimensions of deviants at the same time.}, subject = {Bewusstseinsst{\"o}rung}, language = {en} } @phdthesis{Campbell2015, author = {Campbell, Marlen Jamie-Lee}, title = {Organizational cultures' impact on employees' corruption}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123251}, school = {Universit{\"a}t W{\"u}rzburg}, pages = {197}, year = {2015}, abstract = {Although many researchers refer to organizational culture as the key to explain employees' organizational corruption (= corruption on behalf of the organization), literature lacks systematic empirical evidence. Through a mixed-method approach this research tries to shed some first lights on this issue with the questions: what characteristics describe an organizational culture that promotes employees' corruption? Does a certain type of organizational culture shape a positive attitude towards organizational corruption? Does organizational culture differ in its impact on different types of corruption? Does organizational culture interact with employees' sex to promote employees' corruption? And, is there a main effect of sex on corruption? A qualitative study investigates the characteristics of a corrupt organizational culture in both general and in particular for managers and employees (Study 1). 14 experts of different occupations were asked about underlying assumptions, values, and norms of a corrupt organizational culture coding the frequency and relationship of their answers. The results showed specific underlying assumptions, values, and norms that were shared by the interviewees and provide first insights into their interrelatedness. In addition, the quantitative field survey (Study 2) analyzed if a corrupt organizational culture shapes a positive attitude towards organizational corruption and if both tangible rewards and lax control mechanism mediate this impact. 131 participants answered questionnaires about their perceived competition in their industry, tangible rewards, lax control mechanism, and their attitude towards both gifting and bribery. Results showed that lax control mechanism (and for gifting also tangible rewards) mediated the positive impact of a corrupt organizational culture on organizational corruption. In addition, men and women did not differ in their attitude towards organizational corruption in a corrupt organizational culture. Finally a web-based experiment investigates if organizational culture shapes employees' corruption (Study 3). In addition this approach also covers if the impact of organizational culture on corruption depends on the type of corruption (organizational corruption vs. counterproductive), and if employees' sex influence corruption and if there is an interaction of organizational culture and sex on employees' corruption. 563 participants had to decide whether they engage in corruption. Although a corrupt organizational culture raises both types of corruption, there was neither a notable main effect of sex nor a high impact interaction effect of both on both types of corruption. Thus, aspects of a corrupt organizational culture seem to influence employees' corruption.}, subject = {Korruption}, language = {en} } @phdthesis{Bakhtiari2015, author = {Bakhtiari, Giti}, title = {The Role of Fluency in Oral Approach and Avoidance}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-118666}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Names of, for instance, children or companies are often chosen very carefully. They should sound and feel good. Therefore, many companies try to choose artificially created names that can easily be pronounced in various languages. A wide range of psychological research has demonstrated that easy processing (high processing fluency) is intrinsically experienced as positive. Due to this positive feeling, easy processing can have profound influences on preferences for names. Topolinski, Maschmann, Pecher, and Winkielman (2014) have introduced a different mechanism that influences the perception of words. Across several experiments they found that words featuring consonantal inward wanderings (inward words) were preferred over words featuring consonantal outward wanderings (outward words). They argued that this was due to the fact that approach and avoidance motivations are activated by articulating inward and outward words, because the pronunciation resembles approach and avoidance behaviors of swallowing and spitting, respectively. They suggested this close link as an underlying mechanism for the so-called in-out effect, but did not test this assumption directly. In the current work, I tested an alternative fluency account of the in-out effect. Specifically, I hypothesized that processing fluency might play a critical role instead of motivational states of approach and avoidance being necessarily activated. In Chapter 1, I introduce the general topic of my dissertation, followed by a detailed introduction of the research area of approach and avoidance motivations in Chapter 2. In Chapter 3, I narrow the topic down to orally induced approach and avoidance motivations, which is the main topic of my dissertation. In Chapter 4, I introduce the research area of ecological influences on psychological processes. This chapter builds the base for the idea that human language might serve as a source of processing fluency in the in-out effect. In the following Chapter 5, I elaborate the research area of processing fluency, for which I examined whether it plays a role in the in-out effect. After an overview of my empirical work in Chapter 6, the empirical part starts with Study 1a and Study 1b (Chapter 7) that aimed to show that two languages (Eng. \& Ger.) in which the in-out effect has originally been found might feature a source of higher processing fluency for inward over outward words. The results showed that higher frequencies of inward dynamics compared to outward dynamics were found in both languages. This can lead to higher pronunciation fluency for inward compared to outward words which might in turn lay the ground for higher preferences found for inward over outward words. In Chapter 8, the assumption that inward compared to outward dynamics might be more efficient to process was tested directly in experiments that examined objective as well as subjective processing fluency of artificially constructed non-words featuring pure inward or outward dynamics. Studies 2a-4b found an objective as well as subjective processing advantage for inward over outward words. In Chapter 9, the causal role of objective and subjective pronunciation fluency in the in-out effect was examined. In Study 5 mediational analyses on item-level and across studies were conducted using objective and subjective fluency as possible mediating variables. In Study 6 mediation analyses were conducted with data on subject- and trial-level from a within-subject design. Overall, the data of the item-based, subject-based and trial-based mediation analyses provide rather mixed results. Therefore, an experimental manipulation of fluency was implemented in the last two studies. In Chapter 10, Study 7 and Study 8 demonstrate that manipulating fluency experimentally does indeed modulate the attitudinal impact of consonantal articulation direction. Articulation ease was induced by letting participants train inward or outward kinematics before the actual evaluation phase. Additionally, the simulation training was intensified in Study 8 in order to examine whether a stronger modulation of the in-out effect could be found. Training outward words led to an attenuation and, after more extensive training, even to a reversal of the in-out effect, whereas training inward words led to an enhancement of the in-out effect. This hints at my overall hypothesis that the explicit preferences of inward and outward words are, at least partially, driven by processing fluency. Almost all studies of my dissertation, except for one analysis of the item-based mediation study, speak in favor of the hypothesis that inward words compared to outward words are objectively and subjectively easier to articulate. This possibly contributes partially to a higher preference of inward over outward words. The results are discussed in Chapter 11 with respect to processing fluency and to the role of language as an ecological factor. Finally, future research ideas are elaborated.}, subject = {Sozialpsychologie}, language = {en} }