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Die Erleichterung von einem körperlichen Schmerzreiz besitzt appetitiven Charakter (Leknes et al., 2008; 2011; Seymour et al., 2005), aktiviert belohnungsassoziierte Hirnstrukturen (Leknes et al., 2011; Leknes & Brock, 2014; Leknes & Tracey, 2008; Navratilova & Porreca, 2014) und fördert durch ihre Konditionierbarkeit als Erleichterungslernen bezeichnete appetitive Lern- und Konditionierungsprozesse (Andreatta et al., 2010, 2012; 2013; 2017; Gerber et al., 2014; Tanimoto et al., 2004; Yarali et al., 2008).
Die vorliegende Arbeit bestätigt das angewandte Versuchsparadigma als valides Modell für Erleichterungslernen im Menschen und zeigt erstmals, dass der appetitive Charakter von Schmerzerleichterung auch in Jugendlichen konditionierbar ist. Erfolgreiches Erleichterungslernen zeigte sich dabei in der untersuchten Stichprobe lediglich auf impliziter, nicht aber auf expliziter, kognitiver Ebene. Dies stützt Thesen und vorherige Forschungsbefunde einer Dualität assoziativen Lernens in ein implizites Lernen, welches vornehmlich subkortikale Strukturen erfordert und ein explizites Lernen, das vorrangig kortikale Strukturen wie den präfrontalen Cortex involviert (Andreatta et al., 2010; Strack & Deutsch, 2004; Williams et al., 2001). Die Beobachtungen einer differenten Furcht- versus Erleichterungs-Extinktion bestärken die Thesen eines diversen neuronalen Hintergrunds dieser beiden Lernformen (Diegelmann et al., 2013; Gerber et al., 2014; Yarali et al., 2009; Yarali & Gerber, 2010). Gleichzeitig werfen die Studienergebnisse die Frage auf, ob und inwiefern im Erleichterungslernen von Jugendlichen Unterschiede zu jenem in Erwachsenen bestehen.
Die Hypothese einer verstärkten Akquisition von Erleichterungslernen bei Jugendlichen mit NSSV im Vergleich zu gesunden Jugendlichen ließ sich in der vorliegenden Studie nicht bestätigen. Somit liefern die Ergebnisse keinen direkten Hinweis darauf, dass ein verstärktes Lernen durch Schmerzerleichterung an der Ätiopathogenese von NSSV beteiligt sein könnte. Die vorliegende Arbeit zeigte vielmehr die Tendenz eines abgeschwächten impliziten Erleichterungslernens bei den Jugendlichen mit NSSV. Die tendenziellen Gruppenunterschiede ließen sich nicht hinreichend durch eine differente aktuelle Stimmungslage oder durch eine unterschiedlich starke Ausprägung aversiver emotionaler Anspannungen oder momentaner Angstaffekte erklären. Innerhalb der Gruppe Jugendlicher mit NSSV zeigte sich auch kein Hinweis darauf, dass der Erfolg von Erleichterungslernen vom Schweregrad des NSSV oder von der aktuellen Einnahme von Antidepressiva abhängig sein könnte. Explorative Analysen ergaben, dass Gruppeneffekte in der vorliegenden Studie womöglich aufgrund einer statistischen Unterschätzung, bedingt durch einen zu geringen Stichprobenumfang, nicht das Signifikanzniveau erreichten und dass Unterschiede im Erleichterungslernen von Jugendlichen mit und ohne NSSV tatsächlich sogar noch stärker ausgeprägt sein könnten. Somit sollte die vorliegende Arbeit als Pilotstudie für zukünftige größer angelegte Studien zu Erleichterungslernen bei NSSV betrachtet werden.
Zukünftige Studien erscheinen insbesondere sinnvoll mit Blick auf die hohe klinische sowie gesellschaftliche Relevanz von NSSV für welches, trotz der hohen Prävalenzen und des deutlich erhöhten Morbiditäts- und Mortalitätsrisikos, zum aktuellen Zeitpunkt noch keine hinreichenden Erklärungsmodelle bestehen. Die Studie bestätigte das Vorliegen eines erhöhten Grades aversiver emotionaler Anspannung in Jugendlichen mit NSSV, welcher zuvor nur an Erwachsenen mit einer BPD untersucht und festgestellt worden war (Niedtfeld et al., 2010; Stiglmayr et al., 2005). Die Abnahme negativer Affekte bei den Jugendlichen mit NSSV im Studienverlauf repliziert die Ergebnisse vorheriger Studien, in denen eine Reduktion selbst-berichteter negativer Affekte durch die Beendigung eines Schmerzreizes beobachtet wurde (Bresin et al., 2010; Bresin & Gordon, 2013). Damit bestärken die Studienergebnisse bestehende Erklärungsmodelle für NSSV, welche eine entscheidende Beteiligung der körperlichen Schmerzen und der Schmerzerleichterung bei der Selbstverletzung an der Affektregulation vermuten. Weiterhin wirft die vorliegende Arbeit die Frage auf, welche Rolle eine veränderte Wahrnehmung von Schmerz und Schmerzerleichterung in der Ätiopathogenese von NSSV einnimmt und wie diese sich auf Lernprozesse auswirkt.
Insgesamt erbrächten weitere Erkenntnisse über den potenziellen Zusammenhang von NSSV und abweichendem Erleichterungslernen ein besseres Verständnis für Mechanismen der Entstehung und Aufrechterhaltung von NSSV und böten zudem möglicherweise Ansätze für neue Therapiemöglichkeiten des Störungsbildes.
Defensive behaviors in response to threats are key factors in maintaining mental and physical health, but their phenomenology remains poorly understood. Prior work reported an inhibition of oculomotor activity in response to avoidable threat in humans that reminded of freezing behaviors in rodents. This notion of a homology between defensive responding in rodents and humans was seconded by concomitant heart rate decrease and skin conductance increase. However, several aspects of this presumed defense state remained ambiguous. For example, it was unclear whether the observed oculomotor inhibition would 1) robustly occur during preparation for threat-avoidance irrespective of task demands, 2) reflect a threat-specific defensive state, 3) be related to an inhibition of somatomotor activity as both motion metrics have been discussed as indicators for freezing behaviors in humans, and 4) manifest in unconstrained settings.
We thus embarked on a series of experiments to unravel the robustness, threat-specificity, and validity of previously observed (oculo)motor and autonomic dynamics upon avoidable threat in humans. We provided robust evidence for reduced gaze dispersion, significantly predicting the speed of subsequent motor reactions across a wide range of stimulus contexts. Along this gaze pattern, we found reductions in body movement and showed that the temporal profiles between gaze and body activity were positively related within individuals, suggesting that both metrics reflect the same construct. A simultaneous activation of the parasympathetic (i.e., heart rate deceleration) and sympathetic (i.e., increased skin conductance and pupil dilation) nervous system was present in both defensive and appetitive contexts, suggesting that these autonomic dynamics are not only sensitive to threat but reflecting a more general action-preparatory mechanism. We further gathered evidence for two previously proposed defensive states involving a decrease of (oculo)motor activity in a naturalistic, unconstrained virtual reality environment. Specifically, we observed a state consisting of a cessation of ongoing behaviors and orienting upon relatively distal, ambiguous threat (Attentive Immobility) while an entire immobilization and presumed allocation of attention to the threat stimulus became apparent upon approaching potential threat (Immobility under Attack).
Taken together, we provided evidence for specific oculomotor and autonomic dynamics upon increasing levels of threat that may inspire future translational work in rodents and humans on shared mechanisms of threat processing, ultimately supporting the development of novel therapeutic approaches.
This dissertation explores the development and assessment of inhibitory control – a crucial component of executive functions – in young children. Inhibitory control, defined as the ability to suppress inappropriate responses (Verbruggen & Logan, 2008), is essential for adaptable and goal-oriented behavior. The rapid and non-linear development of this cognitive function in early childhood presents unique challenges for accurate assessment. As children age, they often exhibit a ceiling effect in terms of response accuracy (Petersen et al., 2016), underscoring the need to consider response latency as well. Ideally, combining response latency with accuracy could yield a more precise measure of inhibitory control (e.g., Magnus et al., 2019), facilitating a detailed tracking of developmental changes in inhibitory control across a wider age spectrum. The three studies of this dissertation collectively aim to clarify the relationship between response accuracy, response latency, and inhibitory control across different stages of child development. Each study utilizes a computerized Pointing Stroop Task (Berger et al., 2000) to measure inhibitory control, examining the task's validity and the integration of dual metrics for a more comprehensive evaluation.
The first study focuses on establishing the validity of using both response accuracy and latency as indicators of inhibitory control. Utilizing the framework of explanatory item-response modeling (De Boeck & Wilson, 2004), the study revealed how the task characteristics congruency and item position influence both the difficulty level and timing aspects in young children’s responses in the computerized Pointing Stroop task. Further, this study found that integrating response accuracy with latency, even in a basic manner, provides additional insights. Building upon these findings, the second study investigates the nuances of integrating response accuracy and latency, examining whether this approach can account for age-related differences in inhibitory control. It also explores whether response latencies may contain different information depending on the age and proficiency of the children. The study leverages novel and established methodological perspectives to integrate response accuracy and latency into a single metric, showing the potential applicability of different approaches for assessing inhibitory control development. The third study extends the investigation to a longitudinal perspective, exploring the dynamic relationship between response accuracy, latency, and inhibitory control over time. It assesses whether children who achieve high accuracy at an earlier age show faster improvement in response latency, suggesting a non-linear maturation pathway of inhibitory control. The study also examines if the predictive value of early response latency for later fluid intelligence is dependent on the response accuracy level.
Together, these empirical studies contribute to a more robust understanding of the complex interaction between inhibitory control, response accuracy, and response latency, facilitating valid evaluations of cognitive capabilities in children. Moreover, the findings may have practical implications for designing educational strategies and clinical interventions that address the developmental trajectory of inhibitory control. The nuanced approach advocated in this dissertation suggests prioritizing accuracy in assessment and interventions during the early stages of children's cognitive development, gradually shifting the focus to response latency as children mature and secure their inhibitory control abilities.
Human prosociality, encompassing generosity, cooperation, and volunteering, holds a vital role in our daily lives. Over the last decades, the question of whether prosociality undergoes changes over the adult lifespan has gained increased research attention. Earlier studies suggested increased prosociality in older compared to younger individuals. However, recent meta-analyses revealed that this age effect might be heterogeneous and modest. Moreover, the contributing factors and mechanisms behind these age-related variations remain to be identified. To unravel age-related differences in prosociality, the first study of this dissertation employed a meta-analytical approach to summarize existing findings and provide insight into their heterogeneity by exploring linear and quadratic age effects on self-reported and behavioral prosociality. Additionally, two empirical research studies investigated whether these age-related differences in prosociality were observed in real life, assessed through ecological momentary assessment (Study 2), and in a controlled laboratory setting by applying a modified dictator game (Study 3). Throughout these three studies, potential underlying behavioral and computational mechanisms were explored. The outcome of the meta-analysis (Study 1) revealed small linear age effects on prosociality and significant age group differences between younger and older adults, with higher levels of prosociality in older adults. Explorative evidence emerged in favor of a quadratic age effect on behavioral prosociality, indicating the highest levels in midlife. Additionally, heightened prosocial behavior among middle-aged adults was observed compared to younger adults, whereas no significant differences in prosocial behavior were noted between middle-aged and older adults. Situational and contextual features, such as the setting of the study and specific paradigm characteristics, moderated the age-prosociality relationship, highlighting the importance of the (social) context when studying prosociality. For Study 2, no significant age effect on real-life prosocial behavior was observed. However, evidence for a significant linear and quadratic age effect on experiencing empathy in real life emerged, indicating a midlife peak. Additionally, across all age groups, the link between an opportunity to empathize and age significantly predicted real-life prosocial behavior. This effect, indicating higher levels of prosocial behavior when there was a situation possibly evoking empathy, was most pronounced in midlife. Study 3 presented age differences in how older and younger adults integrate values related to monetary gains for self and others to make a potential prosocial decision. Younger individuals effectively combined both values in a multiplicative fashion, enhancing decision-making efficiency. Older adults showed an additive effect of values for self and other and displayed increased decision-making efficiency when considering the values separately. However, among older adults, individuals with better inhibitory control were better able to integrate information about both values in their decisions. Taken together, the findings of this dissertation offer new insights into the multi-faceted nature of prosociality across adulthood and the mechanisms that help explain these age-related disparities. While this dissertation observed increasing prosociality across the adult lifespan, it also questions the assumption that older adults are inherently more prosocial. The studies highlight midlife as a potential peak period in social development but also emphasize the importance of the (social) context and that different operationalizations might capture distinct facets of prosociality. This underpins the need for a comprehensive framework to understand age effects of prosociality better and guide potential interventions.
Humans actively interact with the world through a wide range of body movements. To understand human cognition in its natural state, we need to incorporate ecologically relevant body movement into our account. One fundamental body movement during daily life is natural walking. Despite its ubiquity, the impact of natural walking on brain activity and cognition has remained a realm underexplored.
In electrophysiology, previous studies have shown a robust reduction of ongoing alpha power in the parieto-occipital cortex during body movements. However, what causes the reduction of ongoing alpha, namely whether this is due to body movement or prevalent sensory input changes, was unknown. To clarify this, study 1 was performed to test if the alpha reduction is dependent on visual input. I compared the resting state alpha power during natural walking and standing, in both light and darkness. The results showed that natural walking led to decreased alpha activity over the occipital cortex compared to standing, regardless of the lighting condition. This suggests that the movement-induced modulation of occipital alpha activity is not driven by visual input changes during walking. I argue that the observed alpha power reduction reflects a change in the state of the subject based on disinhibition induced by walking. Accordingly, natural walking might enhance visual processing and other cognitive processes that involve occipital cortical activity.
I first tested this hypothesis in vision. Study 2 was performed to examine the possible effects of natural walking across visual processing stages by assessing various neural markers during different movement states. The findings revealed an amplified early visual response, while a later visual response remain unaffected. A follow-up study 3 replicated the walking-induced enhancement of the early visual evoked potential and showed that the enhancement was dependent on specific stimulus-related parameters (eccentricity, laterality, distractor presence). Importantly, the results provided evidence that the enhanced early visual responses are indeed linked to the modulation of ongoing occipital alpha power. Walking also modulated the stimulus-induced alpha power. Specifically, it showed that when the target appeared in the fovea area without a distractor, walking exhibited a significantly reduced modulation of alpha power, and showed the largest difference to standing condition. This effect of eccentricity indicates that during later visual processing stages, the visual input in the fovea area is less processed than in peripheral areas while walking.
The two visual studies showed that walking leads to an enhancement in temporally early visual processes which can be predicted by the walking-induced change in ongoing alpha oscillation likely marking disinhibition. However, while walking affects neural markers of early sensory processes, it does not necessarily lead to a change in the behavioural outcome of a sensory task. The two visual studies suggested that the behavioural outcome seems to be mainly based on later processing stages.
To test the effects of walking outside the visual domain, I turned to audition in study 4. I investigated the influence of walking in a particular path vs. simply stepping on auditory processing. Specifically, the study tested whether enhanced processing due to natural walking can be found in primary auditory brain activity and whether the processing preferences are dependent on the walking path. In addition, I tested whether the changed spatial processing that was reported in previous visual studies can be seen in the auditory domain. The results showed enhanced sensory processing due to walking in the auditory domain, which was again linked to the modulation of occipital alpha oscillation. The auditory processing was further dependent on the walking path. Additionally, enhanced peripheral sensory processing, as found in vision, was also present in audition.
The findings outside vision supported the idea of natural walking affecting cognition in a rather general way. Therefore in my study 5, I examined the effect of natural walking on higher cognitive processing, namely divergent thinking, and its correlation with the modulation of ongoing alpha oscillation. I analyzed alpha oscillations and behavioural performance during restricted and unrestricted movement conditions while subjects completed a Guilford's alternate uses test. The results showed that natural walking, as well as missing body restriction, reduces the occipital alpha ongoing power independent of the task phase which goes along with higher test scores. The occipital alpha power reduction can therefore be an indicator of a changed state that allows improved higher cognitive processes.
In summary, the research presented in this thesis highlights that natural walking can change different processes in the visual and auditory domain as well as higher cognitive processes. The effect can be attributed to the movement of natural walking itself rather than to changes in sensory input during walking. The results further indicate that the walking-induced modulation of ongoing occipital alpha oscillations drives the cognitive effects. We therefore suggest that walking changes the inhibitory state which can influence awareness and attention. Such a mechanism could facilitate an adaptive enhancement in cognitive processes and thereby optimize movement-related behaviour such as navigation.
Im Rahmen des interdisziplinären Promotionsschwerpunkts Resilienzfaktoren der Schmerzverarbeitung des evangelischen Studienwerks in Zusammenarbeit mit der Julius-Maximilians-Universität Würzburg und der Otto-Friedrich-Universität Bamberg untersuche ich in diesem Promotionsprojekt den Einfluss von Sicherheit auf die Schmerzverarbeitung. Es ist bekannt, dass die Schmerzverarbeitung durch Emotionen moduliert werden kann. Man geht davon aus, dass negative Emotionen den Schmerz in der Regel verstärken, während positive Emotionen zu einer Schmerzreduktion führen. Frühere Studien fanden heraus, dass die Erwartung eines aversiven Ereignisses zu Bedrohung und stärkeren Schmerzen führt. Es stellt sich die Frage, ob das Gegenteil von Bedrohung, nämlich Sicherheit, zu einer Verringerung der Schmerzen führen kann. Um diese Hypothese zu untersuchen, habe ich drei Experimente an gesunden ProbandInnen durchgeführt.
Trust carries the capacity to shift the focus from risks to opportunities of a situation. Scientific studies from the field of trust research point out that besides situation-specific factors (i.e., stimuli of the environment), cross-situationally stable interindividual differences (i.e., personality) are involved in the emergence of trust. Stable interindividual differences are particularly influential to the subjective experience of situational conditions when crucial information is incomplete. The online shopping environment classifies as a prime example of markets with asymmetric information. Research has examined online consumer trust in the light of signaling theory to understand the effects of trust-enhancing signals. Previous research largely neglects interindividual differences in the perception, processing and reaction to these signals. Against this background, this scientific work has two primary objectives: the investigation of (1) interindividual differences in the evaluation of trust-enhancing signals and (2) a personality-based personalization of trust-enhancing signals in its effect on cognition and behavior. For this purpose, an interactive online shop setup was created, which served as realistic environmental framework. First, the results show a trust-enhancing effect of both objective and subjective personalization, with a superiority of subjective over objective personalization. Second, results suggest a particular susceptibility of the beliefs component of trust. Third, the results suggest that personalization exerts a specifically strong effect in what is, by definition, the particularly uncertain environment of credence goods. Fourth, results indicate that while the trust-enhancing effects of personalization operate (largely) independently of personality, the effect of personality on trust seems to depend on the condition of signal presentation. Taken together, the present work makes a contribution to understanding the effect of personality-adapted signaling environments on the emergence of trust and decision making in the specific context of B2C e-commerce.
Learning accompanies us throughout our lives, from early childhood education through
school, training and university to learning at work. However, much of what we learn is quickly
forgotten. The use of practice tests is a learning strategy that contributes to the acquisition of
sustainable knowledge, i.e. knowledge that is permanently available and can be retrieved when
it is needed. This dissertation first presents findings from previous research on testing in real
educational contexts and discusses theoretically why certain learner or situational
characteristics might influence the effectiveness of the testing effect. Furthermore, a cycle of
three experiments is presented, which were used to investigate whether the positive effect of
practice tests on retention (testing effect) depends on personal or situational characteristics and
also promotes the retention of lecture content that was not directly tested (transfer) in the context
of regular psychology lectures in teacher training courses. In an additional chapter, feedback
from students on the implementation of the study in the classroom context is examined in more
detail. Finally, the results of the three studies are discussed and placed in relation to the theories
presented. The central conclusion from the studies presented is that the testing effect appears to
be a very effective learning strategy that can be used effectively in university teaching and leads
to better learning outcomes regardless of learner characteristics. However, the practice tests
should cover the entire range of relevant content, as transfer effects to non-tested content are
not to be expected.
Anxiety patients overgeneralize fear, also because of an inability to perceptually discriminate threat and safety signals. Therefore, some studies have developed discrimination training that successfully reduced the occurrence of fear generalization. The present work is the first to take a treatment-like approach by using discrimination training after generalization has occurred. Therefore, two studies were conducted with healthy participants using the same fear conditioning and generalization paradigm, with two faces as conditioned stimuli (CSs), and four facial morphs between CSs as generalization stimuli (GSs). Only one face (CS+) was followed by a loud scream (unconditioned stimulus, US). In Study 1, participants underwent either fear-relevant (discriminating faces) or fear-irrelevant discrimination training (discriminating width of lines) or a non-discriminative control training between the two generalization tests, each with or without feedback (n = 20 each). Generalization of US expectancy was reduced more effectively by fear-relevant compared to fear-irrelevant discrimination training. However, neither discrimination training was more effective than non-discriminative control training. Moreover, feedback reduced generalization of US expectancy only in discrimination training. Study 2 was designed to replicate the effects of the discrimination-training conditions in a large sample (N = 244) and examine their benefits in individuals at risk for anxiety disorders. Again, feedback reduced fear generalization particularly well for US expectancy. Fear relevance was not confirmed to be particularly fear-reducing in healthy participants, but may enhance training effects in individuals at risk of anxiety disorder. In summary, this work provides evidence that existing fear generalization can be reduced by discrimination training, likely involving several (higher-level) processes besides perceptual discrimination (e.g., motivational mechanisms in feedback conditions). Its use may be promising as part of individualized therapy for patients with difficulty discriminating similar stimuli.
Virtual humans (VHs) hold immense potential for collaboration in social virtual reality (VR). As VR technology advances, it's vital to assess the psychological effects on VH trust and user privacy to build meaningful social interactions in VR. In social VR, users must be able to trust the VHs they interact with as they navigate through socio-cultural activities. The evaluation of trustworthiness in VHs profoundly impacts interaction quality and user willingness to engage. Conversely, untrustworthy VHs can harm user experiences, privacy, and VR engagement. To address this, we conducted immersive VR studies, exploring how psychological factors influence user's VH trust evaluation under various psychological conditions. This research is pivotal for developing strategies to enhance user privacy, establish secure VR environments, and create a foundation of trust that supports immersive socio-cultural experiences in VR.
To date, there are no established interpersonal trust measurement tools specifically for VHs in VR. In study 1 (the familiarity study) of the current thesis the VR-adjusted version of the social conditioned place preference paradigm (SCPP) by Kiser et al., (2022) was identified as a potential trust measurement tool. We tested whether the familiarity of a VH influenced trust as measured with the SCPP paradigm and other self-defined outcome measures, in a Computer Augmented Virtual Environment (CAVE). The CAVE is a VR system that combines immersive VR with real-world elements. It consists of a room-sized space where the walls are used as projection screens to display virtual scenes and objects. In this within - subject design (n = 20), half of the participants were familiarized with one VH and tasked to explore and interact in a realistic looking virtual art museum environment. The participant’s evaluation of the VH’s trustworthiness was measured as well as their subsequent trust behaviours. Results revealed no significant differences in the evaluation of the VH’s trustworthiness nor any behavioural differences between conditions. The findings of the impact of a VH’s familiarity on trust is inconclusive due to the major limitations of the paradigm. We concluded that the SCPP paradigm needs further validation and the proposed proxies of trust need to be re-evaluated. The findings were considered in the following study.
The virtual maze paradigm design of Hale, (2018) was identified as a potential trust measurement tool, however several limitations are associated with its use to measure trust in VR. In study 2 (a validation study), improvements were made to the virtual maze paradigm of Hale, (2018) and a variant of this paradigm was implemented. We conducted a validation study with 70 participants in a between-subject design with VH trustworthiness as the between-subject factor. Participants wore a head-mounted display (HMD), to deliver an immersive VR experience. In our version of the virtual maze, it was the task of the users (the trustors) to navigate through a maze in VR, where they could interact with a VH (the trustee). They could choose to ask for advice and follow the advice from the VH if they wanted to. The number of times participants asked and followed advice and the time it took to respond to the given advice served as behavioural proxies/measures of trust. The two conditions (trustworthy vs. untrustworthy) did not differ in the content of the advice but in the appearance, tone of voice and engagement of the trustees (allegedly an avatar controlled by other participants). Results indicated that the experimental manipulation was successful, as participants rated the VH as more trustworthy in the trustworthy condition compared with the VH in the untrustworthy condition. Importantly, this manipulation affected the trust behaviour of participants, who, in the trustworthy condition, asked for advice and followed advice more often, indicating that the paradigm is sensitive to differences in VH’s trustworthiness. Thus, our paradigm can be used to measure differences in interpersonal trust towards VHs and may serve as a valuable research tool for researchers who study trust in VR. Therefore, study 2 fills the gap in the literature, for an interpersonal trust measurement tool specifically for VHs in VR.
Two experimental studies, with a sample size of 50 participants each, utilized the virtual maze paradigm where participants entered 12 rooms under different conditions. We examined the influence of cognitive load (CL) on trust towards VH in VR in study 3 (Cognitive load study), and the influence of emotional affect (Emotional affect study) on trust towards VH in VR in study 4 (EA study). In both studies, we assessed participant’s evaluation of a VH’s trustworthiness, along with three behavioural indicators of trust in the maze task: 1) frequency of advice asked, 2) frequency of advice followed, and 3) the time taken by participants to execute the received advice. In study 3, the CL was manipulated with the auditory 1-back task in the high cognitive load condition (HCL). In study 4, the Autobiographical Emotional Memory Task (AEMT) was used to manipulate the EA of participants in the negative emotional affect (NEA) condition. As an additional manipulation, while participants were immersed in VR, they were exposed to 12 negative pictures and sounds that was presented simultaneously to strengthen the initial manipulation. The manipulation of the within-subject factors (CL and EA) was successful in both studies, as significant differences between conditions were observed in both studies (higher CL in the HCL condition and a more negative EA in the NEA condition). However, only CL influenced participant’s evaluation of the VH’s trustworthiness. The VH were evaluated as significantly more trustworthy after the HCL condition. Despite the difference in trust evaluation, there was no difference in advice asking or following. Participants in study 4 asked and followed advice due to their trust in the VH and asked and followed advice equally often in both conditions. Importantly, significant differences were observed in the participants response times in both studies. In study 3 during the HCL condition participants followed advice quicker. The order in which the conditions were presented influenced the experience of CL. Participants experienced higher levels of CL and responded to advice significantly faster when low cognitive load (LCL) was presented as the first condition compared with LCL as the second condition. In study 4 participants in the NEA condition followed advice slower similar to the findings of study 3. The order in which the conditions were presented had a significant effect on the EA. Participants asked and followed advice less when the NEA condition was presented first compared with when it is presented second. Possible explanations for the findings are discussed in the thesis.
Overall, this thesis offers a novel tool for trust measurement (the virtual maze paradigm) and contributes to understanding the role of psychological factors in trust towards virtual humans in virtual reality.