Habituation of salivary cortisol and cardiovascular reactivity to a repeated real-life and virtual reality Trier Social Stress Test.

BACKGROUND: Although the Trier Social Stress Test (TSST) constitutes a valid paradigm for social stress induction, less is known about the effects of a virtual reality (VR) TSST on short- and long-term hypothalamic-pituitary-adrenal (HPA) axis and sympathetic-adreno-medullar (SAM) axis responses. Hence, this study set out to evaluate reactivity and habituation of self-reported stress and HPA and SAM reactivity in a real TSST and VR-TSST when compared to a placebo TSST. METHOD: Sixty-eight healthy young adults (50% female) were randomly assigned to either a real TSST, a VR-TSST, or a placebo TSST, all of which were conducted three times (one day and one week post initial exposure). Social presence, self-reported stress, salivary cortisol, heart rate (HR), and heart rate variability (HRV) were analyzed using ANOVAs and multilevel models. FINDINGS: On the first exposure, both the real and VR-TSST showed significantly stronger cortisol and cardiovascular responses than the placebo. On the second visit, the cortisol response was still significantly high-and the HRV response low-for the real and VR-TSST. The third visit resulted in HR, HRV, and cortisol responses comparable to the placebo group. Furthermore, the real TSST induced more self-reported stress than the placebo on all three visits, the VR-TSST only on the first two visits. Social presence was stable across conditions and had no association with stress markers. CONCLUSION: These findings imply that the replicability of stress exposures at shorter intervals seems problematic for the traditional TSST, and for the VR-TSST.

Virtual and real-life ostracism and its impact on a subsequent acute stressor.

While ostracism constitutes a social stressor with negative effects on physical and mental health, social inclusion seems to increase resilience. This may be true not only for face-to-face settings, but also for computer-mediated interactions. Hence, this study examined the differences between ostracism and social inclusion in real-life or Virtual Reality (VR) regarding self-reported stress, neuroendocrine and cardiovascular reactivity in a subsequent real-life socio-evaluative task. 84 females were randomly assigned to a 3 (agency: face-to-face/human controlled VR-avatar/computer VR-agent) x 2 (inclusion status: inclusion/exclusion) between-subject design using a Cyberball paradigm. Subsequently, they were exposed to a real-life Trier Social Stress Test (TSST). Results indicate that the experience of ostracism constitutes a threat to fundamental social needs independent of agency. Excluded participants showed cardiovascular reactivity during TSST; also face-to-face and avatar excluded individuals had elevated salivary cortisol levels. Included participants reported more perceived social support during Cyberball and showed a blunted cortisol response to the TSST. These results suggest that face-to-face and avatar-related ostracism provokes responses in the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS). Furthermore, they reveal that social inclusion may act as a stress-protector as it alters HPA- and SNS-related stress responsiveness to subsequent stressors.

Physical Presence, Social Presence, and Anxiety in Participants with Social Anxiety Disorder During Virtual Cue Exposure.

Although social anxiety disorders (SADs) are increasingly treated by means of virtual cue exposure, the mechanisms leading to sufficient anxiety levels and thus to a success of virtual reality exposure therapy are still poorly understood. Also, most studies with SAD participants fail to evaluate social presence, although it may be a more appropriate indicator for virtual social stress scenarios than physical presence. Hence, for the first time, this study sets out to examine the link between social presence, physical presence, and emotional responses to phobogenic virtual social stimuli. A group of n = 12 participants with SAD and n = 12 healthy controls were exposed to three social tasks in an interactive virtual environment (VE). Self-report measures of physical and social presence as well as state anxiety were used alongside heart rate measures to evaluate the virtual experience. Results show significantly higher anxiety levels-both self-report and physiological-in SAD participants than in controls. Also, socially anxious subjects reported to experience more copresence and mutual attention as well as a higher sense of being in the VE than their healthy peers. In sum, social presence experiences may be more predicative of the anxiety response in SAD individuals than physical presence. Especially attentional processes seem to crucially shape the interplay between presence and affective responses.

Virtual social support buffers stress response: An experimental comparison of real-life and virtual support prior to a social stressor.

BACKGROUND AND OBJECTIVES: Face-to-face and text-based social support have been shown to attenuate stress responses in past studies. Yet as social interactions increasingly take place online by means of virtual humans, our objective was to examine whether different forms of social support (virtual vs. real) prior to the Trier Social Stress Test (TSST) would also decrease stress. Additionally, the effect on subsequent real-life social behaviors (helping and approach) was evaluated while controlling for affective states and social presence. METHODS: 56 participants were either supported by an avatar, an agent, a real human or received no support before completing the TSST and two subsequent social behavior tasks (pen task and seating task). RESULTS: Results show no difference in agency regarding social presence. Yet, participants with agent support and no support had significantly higher heart rates during the TSST and reported to be more worried. Also, they were more irritated and showed significantly slower helping reactions (picking up pens). LIMITATIONS: A limitation to this study is that only emotional verbal and non-verbal support were provided by a stranger. Different forms of support as well as a different source (i.e., a friend) may have a more pronounced effect on stress buffering. CONCLUSIONS: Virtual social support is as effective as face-to-face support in terms of stress buffering, as long as the recipient has the impression that it is provided by another human (via an avatar). This has wide ranging implications not only for health-related application in prevention and treatment but also for further research.

Agency and Gender Influence Older Adults' Presence-Related Experiences in an Interactive Virtual Environment.

While virtual humans are increasingly used to benefit the elderly, considerably little is still known about older adults' virtual experiences. However, due to age-related changes, older adults' perceptions of virtual environments (VEs) may be unique. Hence, our objective was to examine possible gender differences in immersion, flow, and emotional states as well as physical and social presence in elderly males and females interacting either with a computer-controlled agent or a human-controlled avatar. Seventy-eight German-speaking older adults were randomly assigned to an avatar or an agent condition and were exposed to a brief social encounter in a virtual café. Results indicate no overall gender differences, but a significant effect of agency on social presence, physical presence, immersion, and flow. Participants in the avatar condition reported higher levels in all measures, except for involvement. Furthermore, significant gender × agency interactions were found, with females showing more social presence, spatial presence, and flow when interacting with a human-controlled avatar and more realism when conversing with an agent. Also, all participants showed significant changes in their affect post exposure. In sum, older adults' virtual experiences seem to follow unique patterns, yet, they do not preclude the elderly from successfully participating in VEs.

Afraid to be there? Evaluating the relation between presence, self-reported anxiety, and heart rate in a virtual public speaking task.

The link between anxiety and presence in a virtual environment (VE) is still a subject of an unresolved debate, with little empirical research to support theoretical claims. Thus, the current study analyzed presence, self-reported anxiety, and a physiological parameter (heart rate [HR]) in a sample of 30 high anxious and 35 low anxious participants. Both groups delivered a 5 minute speech in a virtual lecture hall. Results indicate no mediating influences of presence on group differences in self-reported state anxiety during the speech, but point toward negative correlations between state anxiety and the iGroup Presence Questionnaire (IPQ) scales "sense of being there" and "realism." Furthermore, HR was found to be unrelated to self-reported presence. Only the IPQ scale "spatial presence" showed a marginally significant influence on group differences in state anxiety. The present results support the assumption that presence and anxiety are logically distinct, meaning that presence does not directly influence the intensity of an emotion felt in a VE. Rather, it constitutes a precondition for an emotion to be at all elicited by a VE. Also, HR has proven to be no adequate substitute measure for presence, since it only assesses anxiety not presence. It may, however, mediate the interplay between trait anxiety and state anxiety. Possible implications of the current findings are discussed alongside the problem of using presence questionnaires that seem to be prone to subjective bias (i.e., participants confusing presence and emotion).