A virtual reality approach to the Trier Social Stress Test: Contrasting two distinct protocols

Logical decisions after a psychosocial stressor: The late phase of acute stress reduces loss aversion

Loss aversion, the principle that losses have a greater impact on decision-making than gains, can be modulated by stress. Most findings reported that stress reduces loss aversion, in line with the alignment hypothesis. Yet, decision-making was always assessed at the early stages of the stress response. Instead, the latter phase of the stress response enhances the salience-network and then, it could amplify the salience of losses, thereby increasing loss aversion. To our knowledge, it has never been studied how the latter stress response influences loss aversion and our aim is to fill this gap. 92 participants were divided into experimental and control group. The first one was exposed to the Trier Social Stress Test, and controls viewed a match-length distractor video. Both groups performed a mixed gamble task to measure loss aversion through a Bayesian-computational model. During and after the stressor, experimental group exhibited signs of both physiological and psychological stress which indicated that stress induction was effective. However, rather than increasing, loss aversion of stressed participants was lower. These results constitute a new evidence of stress influencing loss aversion and are discussed within the alignment hypothesis, according to which stress aligns sensitivity to gains and losses.

Later stages of acute stress impair reinforcement-learning and feedback sensitivity in decision making

Whereas the effects of the early stages of acute stress seem to improve learning and increase loss aversion in decision making, in later stages, the opposite has been found, an impairment in decision making probably due to higher reward-attraction, as the STARS approach suggests. This study aims to investigate the effects of the later stages of acute stress on decision making and its underlying processes using a computational model. We hypothesized that stress would affect underlying cognitive strategies during decision making. Ninety-five participants were randomly distributed into two groups, experimental (N = 46) and control (N = 49). A virtual version of The Trier Social Stress Test (TSST) was used as a laboratory stressor. After 20minutes, decision making was assessed by using the Iowa Gambling Task (IGT). The Value-Plus-Preservation (VPP) RL computational model was used to extract decision-making components. As expected, the stressed participants showed deficits in IGT performance on reinforcement-learning and feedback sensitivity. However, there was no gains attraction. These results are discussed by considering that decision making in later stages of acute stress could be based on impairments in prefrontal cortex functioning.

Stressed individuals exhibit pessimistic bursting beliefs and a lower risk preference in the balloon analogue risk task

Stress alters decision-making by usually promoting risk-taking and reward-seeking, which could be advantageous in a context where risk is rewarded, such as the Balloon Analogue Risk Task (BART). However, previous studies addressing this issue showed inconsistencies which could emerge from assessing decision-making as a single dimension. Our aim is to study through computational modelling how stress influences cognitive subprocesses of the decision-making during the BART. For this purpose, 94 healthy participants were submitted to BART, but only half were exposed to the virtual Trier Social Stress Test (TSST-VR). The Experimental-Weight Mean-Variance (EWMV) model was used to gain insight into the subprocesses involved in risk-taking during BART. Rather than reward-seeking, our results showed a pessimistic prior belief about the balloons bursting likelihood, and a lower risk preference in the stressed participants. This cautious attitude could be attributable to an alertness state promoted by stress. Yet, since risk is rewarded in BART, it could also evidence a maladaptive decision-making derived from learning difficulties and altered feedback-processing under stress.

Automated Stress Recognition Using Supervised Learning Classifiers by Interactive Virtual Reality Scenes

Virtual reality (VR) technology offers a great opportunity to explore stress disorder therapies. We created a VR stress training system, which incorporates three highly interactive stressful scenes to elicit stress, and demonstrate the concurrent variations between physiological data (heart rate, electrodermal activity and eye-blink rate) and self-reported stress ratings through a self-designed customized perceived stress questionnaire (SSAI) and wearable devices. Several supervised learning models were rigorously applied to automate stress recognition. Our findings include the evaluations of the VR system by computing Cronbach's alpha ( α = 0.72 ) and Kaiser-Meyer-Olkin (KMO) coefficient ( η = 0.78 ) through a retrospective survey, which were subsequently confirmed as reliable on four aspects (sense of presence, sense of space, sense of immersion and sense of reality) via factor analysis. Additionally, we demonstrate the effectiveness of physiology-based stress level classification (no stress, low stress and high stress) and continuous SSAI score prediction, with accuracy reaching 0.742 by bagging ensemble learning model and goodness-of-fit reaching 0.44 via multivariate stepwise regression. This study provides detailed insight regarding the effect of objective physiological measures on the validation of subjective self-ratings under a novel complex VR stress training system, which stimulates the further investigations of stress disorder recognition and treatment.

Inducing and Recording Acute Stress Responses on a Large Scale With the Digital Stress Test (DST): Development and Evaluation Study

Background

Valuable insights into the pathophysiology and consequences of acute psychosocial stress have been gained using standardized stress induction experiments. However, most protocols are limited to laboratory settings, are labor-intensive, and cannot be scaled to larger cohorts or transferred to daily life scenarios.

Objective

We aimed to provide a scalable digital tool that enables the standardized induction and recording of acute stress responses in outside-the-laboratory settings without any experimenter contact.

Methods

On the basis of well-described stress protocols, we developed the Digital Stress Test (DST) and evaluated its feasibility and stress induction potential in a large web-based study. A total of 284 participants completed either the DST (n=103; 52/103, 50.5% women; mean age 31.34, SD 9.48 years) or an adapted control version (n=181; 96/181, 53% women; mean age 31.51, SD 11.18 years) with their smartphones via a web application. We compared their affective responses using the international Positive and Negative Affect Schedule Short Form before and after stress induction. In addition, we assessed the participants’ stress-related feelings indicated in visual analogue scales before, during, and after the procedure, and further analyzed the implemented stress-inducing elements. Finally, we compared the DST participants’ stress reactivity with the results obtained in a classic stress test paradigm using data previously collected in 4 independent Trier Social Stress Test studies including 122 participants overall.

Results

Participants in the DST manifested significantly higher perceived stress indexes than the Control-DST participants at all measurements after the baseline (P<.001). Furthermore, the effect size of the increase in DST participants’ negative affect (d=0.427) lay within the range of effect sizes for the increase in negative affect in the previously conducted Trier Social Stress Test experiments (0.281-1.015).

Conclusions

We present evidence that a digital stress paradigm administered by smartphone can be used for standardized stress induction and multimodal data collection on a large scale. Further development of the DST prototype and a subsequent validation study including physiological markers are outlined.

Stress research during the COVID-19 pandemic and beyond

The COVID-19 pandemic confronts stress researchers in psychology and neuroscience with unique challenges. Widely used experimental paradigms such as the Trier Social Stress Test feature physical social encounters to induce stress by means of social-evaluative threat. As lockdowns and contact restrictions currently prevent in-person meetings, established stress induction paradigms are often difficult to use. Despite these challenges, stress research is of pivotal importance as the pandemic will likely increase the prevalence of stress-related mental disorders. Therefore, we review recent research trends like virtual reality, pre-recordings and online adaptations regarding their usefulness for established stress induction paradigms. Such approaches are not only crucial for stress research during COVID-19 but will likely stimulate the field far beyond the pandemic. They may facilitate research in new contexts and in homebound or movement-restricted participant groups. Moreover, they allow for new experimental variations that may advance procedures as well as the conceptualization of stress itself. While posing challenges for stress researchers undeniably, the COVID-19 pandemic may evolve into a driving force for progress eventually.

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.

Evaluation of a remote, internet-delivered version of the Trier Social Stress Test

The Trier Social Stress Test (TSST) is a widely used, reliable, and ecologically valid method for inducing acute stress under controlled conditions. Traditionally, the TSST is administered with staff physically present with participants, which limits the participant populations that can be exposed to the TSST. We describe an adaptation of the TSST to remote, online delivery over video-conferencing, which we call the internet-delivered Trier Social Stress Test (iTSST). This adaption has participants use wearable, self-administered ECG monitors received and returned via mail. Fifty participants were recruited to take part in a pilot study evaluating stress-reduction interventions and completed the iTSST at two occasions separated by approximately 12 weeks. Perceived stress and heart rate variability (HRV) were measured during both administrations of the iTSST. Forty-one participants completed both assessments and were included in the set of analyses. Both administrations were characterized by an increase in self-reported stress and reduction in self-reported relaxation from the resting phase to the speech task, which returned to baseline during recovery. In terms of HRV, we observed a significant parasympathetic response to the iTSST in 90% of participants, evidenced by a decrease in RMSSD and increase in heart rate from resting to the speech task, which recovered during the recovery phase. In terms of repeatability, there was little evidence of habituation and the iTSST elicited a stress response during both the initial administration and the 12-week follow-up. While the utility is limited by the lack of a measure of sympathetic and HPA-axis activity, the iTSST represents a promising research tool when physically interacting with participants is not feasible.

Validation of an online version of the Trier Social Stress Test in a study of adolescents

INTRODUCTION

The Trier Social Stress Test (TSST) is the most widely used protocol for activating a stress response of the hypothalamic-pituitary-adrenocortical (HPA) axis and other stress-mediating systems. A number of variants of the TSST exist, including ones for children, groups, and virtual reality. All of these versions, though, require in-person assessment. The COVID-19 pandemic has made in-person assessment impossible or extremely difficult and potentially dangerous. The purpose of this study was to validate a completely remote, online, version of the TSST for children.

METHOD

A sample of 68 (27 female) 15- and 16-year old participants were administered the TSST-Online (TSST-OL) during the late afternoon hours (3-6 p.m. start time). The participants, judges (one male, one female), and experimenter (female) all joined the assessment from their own homes via the online platform, ZOOM™. Two sessions were conducted, one to obtain consent, explain procedures, work with the family to arrange the computer and room set-up for the TSST-OL and one within two weeks to conduct the procedure. The participants were trained to take their own saliva samples and a saliva sampling kit was mailed to the home in between the first and second session. The samples were then mailed to the researchers within a day of collection. The participant was observed during saliva collection to determine correct procedures were followed. Salivary cortisol, salivary α-amylase and self-reports of stress were measured multiple times over the second session.

RESULTS

rmANOVAs yielded a significant effect of trials, for cortisol, F(1.37,90.46) = 15.13, p = .001, sAA, F(2.75,146.68) = 6.91, p = .001, and self-rated stress, F(3.43,222.69) = 118.73, p = .001. There were no significant sex by trials interactions for any measure, although females reported more stress than males, F(1,65) = 9.14, p = .004. For cortisol, from baseline to expected peak (30 min after the onset of speech preparation), the Cohen's effect size was dz = 0.57. Using 1.5 nmol/l (or 0.54 μg/dl) as the criterion for a response (Miller, Plessow, Kirschaum, & Stalder, 2013), 63% of the participants produced a significant increase in cortisol.

CONCLUSIONS

The responses to the TSST-OL are consistent with in-person responses among children and adolescents (see recent meta-analysis (Seddon et al., 2020). The protocol is a viable way of assessing reactivity of the HPA axis and other stress systems without needing to bring the participant into the research laboratory. This method will be useful during periods of widespread infection. It should also work to study populations who all live too far from the research laboratory to be assessed in person.

Multi-modal responses to the Virtual Reality Trier Social Stress Test: A comparison with standard interpersonal and control conditions

The Trier Social Stress Test (TSST) is a reliable social-evaluative stressor. To overcome limitations of the in vivo TSST, a standardized virtual reality TSST (VR-TSST) was developed. The present study compares the emotional (anxiety) and physiological (heart period and variability) response to a VR-TSST with an in vivo TSST and a control condition. Participants took part in either an in vivo TSST (N = 106, 64% female), VR-TSST (N = 52, 100% female), or a control TSST (N = 20, 40% female). Mixed linear modeling examined response profile differences related to TSST type. While there was an equivalent anxiety response to the in vivo TSST as the VR-TSST, we found a smaller heart period and heart rate variability response in VR-TSST compared to the in vivo TSST, especially in response to the math part of the test. The present findings demonstrate that social evaluative stress can be successfully induced in a VR setting, producing similar emotional and slightly attenuated cardiovascular responses.

Sex Differences in Stress Reactivity to the Trier Social Stress Test in Virtual Reality

OBJECTIVE

The aims of the present study were twofold: 1) to examine the effects of a virtual reality version of Trier Social Stress Test (TSST-VR) using a placebo as the control condition; 2) to delineate sex differences in psychophysiological responses following the TSST-VR.

METHODS

Healthy young male (n = 30) and female (n = 30) undergraduates were randomly assigned to a psychosocial stress protocol condition or to a non-stressful control condition (placebo) also under virtual reality environment (VR). Electrodermal activity (EDA), heart rate (HR) and heart rate variability (HRV) were measured throughout the condition. The visual analog scale (VAS) was used to assess the perceived stress before and after the condition. We also included subjective scales of emotional states and coping.

RESULTS

Different ANOVAs showed that after VR, the stress group reported higher scores on VAS than the non-stress group. Before VR, compared with females, the males showed stronger EDA and higher HRV. Under VR, the males had lower HR. After VR, the males' HR was still lower than females', but their HRV was higher than females'. Finally, the correlation between subjective and objective reactivity demonstrated that HRV during the experiment was negatively correlated to depression and negative affect. The HRV after VR was negatively correlated to the positive coping but was positively correlated to the depression.

CONCLUSION

These findings suggest that the TSST-VR could be used as an available tool for testing sex differences to psychosocial stress induction in experimental settings. Compared with females, males were more sensitive to stress. The scores on depression, negative affect and positive coping before the stress induction may be able to predict the arousal of the sympathetic nervous system across the stress situations.

The Interaction Between Physical and Psychosocial Stressors

Do physical and psychosocial stressors interact to increase stress in ways not explainable by the stressors alone? A preliminary study compared participants' stress response while subjected to a physical stressor (reduced or full physical load) and a predetermined social stressor (confronted by calm or aggressive behavior). Salivary cortisol samples measured endocrine stress. Heart rate variability (HRV) and electrodermal activity (EDA) measured autonomic stress. Perceived stress was measured via discomfort and stress state surveys. Participants with a heavier load reported increased distress and discomfort. Encountering an aggressive individual increased endocrine stress, distress levels, and perceived discomfort. Higher autonomic stress and discomfort were found in participants with heavier physical load and aggressive individuals. The results suggest a relationship where physical load increases the stressfulness of aggressive behavior in ways not explainable by the effects of the stressors alone. Future research is needed to confirm this investigation's findings.

Negative Social Evaluation Impairs Executive Functions in Adolescents With Excess Weight: Associations With Autonomic Responses

BACKGROUND

Adolescents with excess weight suffer social stress more frequently than their peers with normal weight.

PURPOSE

To examine the impact of social stress, specifically negative social evaluation, on executive functions in adolescents with excess weight. We also examined associations between subjective stress, autonomic reactivity, and executive functioning.

METHODS

Sixty adolescents (aged 13-18 years) classified into excess weight or normal weight groups participated. We assessed executive functioning (working memory, inhibition, and shifting) and subjective stress levels before and after the Trier Social Stress Task (TSST). The TSST was divided into two phases according to the feedback of the audience: positive and negative social evaluation. Heart rate and skin conductance were recorded.

RESULTS

Adolescents with excess weight showed poorer executive functioning after exposure to TSST compared with adolescents with normal weight. Subjective stress and autonomic reactivity were also greater in adolescents with excess weight than adolescents with normal weight. Negative social evaluation was associated with worse executive functioning and increased autonomic reactivity in adolescents with excess weight.

CONCLUSIONS

The findings suggest that adolescents with excess weight are more sensitive to social stress triggered by negative evaluations. Social stress elicited deterioration of executive functioning in adolescents with excess weight. Evoked increases in subjective stress and autonomic responses predicted decreased executive function. Deficits in executive skills could reduce cognitive control abilities and lead to overeating in adolescents with excess weight. Strategies to cope with social stress to prevent executive deficits could be useful to prevent future obesity in this population.

A Virtual Home for the Virtual Clinical Trial

Virtual clinical trials (VCTs) can satisfy the need for rigorous clinical trials by using distributed technological solutions that eliminate the need for a physical trial site. This report explores potential benefits of using virtual reality (VR) to provide a "virtual site" for VCTs, a shared immersive hub in which VCT participants could experience elements of the trial and interact with the trial team. VR is a communication technology that has been emerging alongside the development of VCTs, although they have never been merged in a substantial way. Many of the gaps within the VCT paradigm are areas in which VR excels. VR environments are standardized and precisely uniform, the technology allows introduction of an almost endless set of stimuli to participants' visual and auditory systems, and VR systems are adept at capturing precise movement and behavioral data. Although VR has not yet found its way into VCTs, much of the groundwork for such integration has been laid through research and technological development achieved in the past few years. Future implementation of VR within VCTs could move us from site-less trials to those with a virtual site serving as a hub for trial information provision, interaction with trial representatives, administration of evaluations and assessments, and more.

The Nature of Reality: Human Stress Recovery During Exposure to Biodiverse, Multisensory Virtual Environments

Immersive virtual environments (IVEs) were used to test the effects of biodiversity on recovery from induced stress. Three natural environments and one urban environment were used to represent ordinal levels of biodiversity (none, low, moderate, and high). The four IVEs comprised visual, auditory, and olfactory stimuli. An additional high biodiversity IVE without auditory or olfactory stimuli was also included to study the effects of multisensory stimulation per se on recovery from stress and perceptions of biodiversity. Following stress induction via a novel IVE Trier Social Stress Test (TSST-IVE), heart rate and five self-reported well-being measures were used to assess participants’ recovery after immersion in one of the five IVEs. The results showed consistent well-being responses across both self-reported and physiological measures, suggesting biodiversity does directly affect human well-being. However, the relationship was not linear. For most measures of well-being, stress recovery was least effective in the urban IVE, consistent with past research. The low biodiversity IVE elicited the greatest improvement in all well-being measures except self-reported calmness. One could speculate that the landscape features of the least biodiverse IVE may elicit subconscious preferences toward savanna-like landscapes, as suggested by previous studies. The IVE depicting a moderate level of biodiversity was the least restorative of the natural environments. A multisensory experience was associated with better recovery in all measures of well-being than a visual-only experience, and perceptions of landscape components significantly differed between two identical nature scenes when auditory and olfactory stimuli were removed. Nuances in the data and implications of the findings are discussed. The results signal a need for caution and question the assumption that cultural ecosystem services align with positive outcomes for biodiversity conservation.

HPA axis responses to psychological challenge linking stress and disease: What do we know on sources of intra- and interindividual variability?

Stress is an ubiquitous phenomenon with significant impact on human physiology when it lasts too long, when it is too intense, or when it hits vulnerable individuals. Examining the mechanisms linking stress exposure with health and disease is an important endeavor in psychoneuroendocrine research. Empirical evidence so far revealed large intra- as well as inter-individual variability in hypothalamic-pituitary-adrenal (HPA) axis responses to acute psychosocial stress, showing that the HPA axis is a highly adaptive system. Thus, the characterization of intra- und inter-individual patterns of HPA axis reactivity is of high scientific interest and forms the basis on which mechanistic links between stress response (dys)regulation and health impairments can be examined. To date, basic knowledge has been, and still is, accumulated on demographic, biological (including genetic and epigenetic) factors, lifestyle behavioral variables, consumption of substances and medication, psychological and personality factors, as well as on methodological aspects. Besides this, there is also very recent progress in respect to the development of laboratory stress paradigms that can be applied in virtual reality or inside an MRI-scanner. In sum, the present review updates our current knowledge on moderating and intervening factors as sources of intra- und inter-individual variability in human cortisol stress responses and offers recommendations for future research designs.

Virtually stressed? A refined virtual reality adaptation of the Trier Social Stress Test (TSST) induces robust endocrine responses

In recent years, virtual reality (VR) technology has found its way into nearly all fields of psychology. Previous studies indicated that virtual reality adaptations of the TSST are less potent in stimulating HPA-axis responses, with lower salivary cortisol responses recorded as compared to the in-vivo TSST. (TSST-IV). In the present experiment we tested the stress-induction potential of a refined version of the TSST-VR using a fully orthogonal experimental design in which ninety-three healthy males were either assigned to the TSST condition or a corresponding control condition in a real or virtual environment. We found a significant increase of endocrine, autonomic and self-reported stress markers in both stress conditions. Notably, we found a robust rise in salivary cortisol to the TSST-VR comparable to that observed in the TSST-IV. Despite subtle differences in response between virtual and in vivo settings, we conclude that VR adaptations of in-vivo stressors have the potential to induce real physiological and subjective reactions.

Relationship between resilience and stress: Perceived stress, stressful life events, HPA axis response during a stressful task and hair cortisol

BACKGROUND

There is no consensus about how resilience is related to the different types of stress such as daily or chronic stress and psychopathology. The main objective of this study is to evaluate the relationship between resilience and the different measures of stress such as perceived stress, chronic stress, life events, HPA axis response during a stressful task and psychopathology.

MATERIAL AND METHODS

The design was cross-sectional. Resilience, perceived stress, stressful life events, hair cortisol and HPA axis response during Trier Social Stress Test measured by salivary cortisol samples and psychopathological symptoms were assessed in a sample of 80 University students.

RESULTS

Participants with low resilience showed higher scores in perceived stress level (p < .001), the number of current life events (p < .02), the intensity of stressful events (p < .025) as well as Obsession and Compulsion (p = .006), Interpersonal Sensitivity (p = .028), Phobic Anxiety (p = .044) and psychopathological severity (p = .033). Resilience was associated with chronic stress by perceived stress (p < .001), hair cortisol concentration (p = .022), obsessions and compulsions (p = .016), interpersonal sensitivity (p = .022), and depression symptoms (p = .039).

CONCLUSION

Resilience seems to be determinant in perceived stress, the number of current life events, the intensity of stressful events, chronic stress, obsession and compulsions, interpersonal sensitivity, phobic anxiety and depression symptoms, and psychopathological severity index.

Real-time Acute Stress Facilitates Allocentric Spatial Processing in a Virtual Fire Disaster

Prior studies have shown that spatial cognition is influenced by stress prior to task. The current study investigated the effects of real-time acute stress on allocentric and egocentric spatial processing. A virtual reality-based spatial reference rule learning (SRRL) task was designed in which participants were instructed to make a location selection by walking to one of three poles situated around a tower. A selection was reinforced by either an egocentric spatial reference rule (leftmost or rightmost pole relative to participant) or an allocentric spatial reference rule (nearest or farthest pole relative to the tower). In Experiment 1, 32 participants (16 males, 16 females; aged from 18 to 27) performed a SRRL task in a normal virtual reality environment (VRE). The hit rates and rule acquisition revealed no difference between allocentric and egocentric spatial reference rule learning. In Experiment 2, 64 participants (32 males, 34 females; aged from 19 to 30) performed the SRRL task in both a low-stress VRE (a mini virtual arena) and a high-stress VRE (mini virtual arena with a fire disaster). Allocentric references facilitated learning in the high-stressful VRE. The results suggested that acute stress facilitate allocentric spatial processing.

Autonomic Nervous System Responses to Hearing-Related Demand and Evaluative Threat

PURPOSE

This paper consists of 2 parts. The purpose of Part 1 was to review the potential influence of internal (person-related) factors on listening effort. The purpose of Part 2 was to present, in support of Part 1, preliminary data illustrating the interactive effects of an external factor (task demand) and an internal factor (evaluative threat) on autonomic nervous system measures.

METHOD

For Part 1, we provided a brief narrative review of motivation and stress as modulators of listening effort. For Part 2, we described preliminary data from a study using a repeated-measures (2 × 2) design involving manipulations of task demand (high, low) and evaluative threat (high, low). The low-demand task consisted of repetition of sentences from a narrative. The high-demand task consisted of answering questions about the narrative, requiring both comprehension and recall. During the high evaluative threat condition, participants were filmed and told that their video recordings would be evaluated by a panel of experts. During the low evaluative threat condition, no filming occurred; participants were instructed to "do your best." Skin conductance (sympathetic nervous system activity) and heart rate variability (HRV, parasympathetic activity) were measured during the listening tasks. The HRV measure was the root mean square of successive differences of adjacent interbeat intervals. Twelve adults with hearing loss participated.

RESULTS

Skin conductance increased and HRV decreased relative to baseline (no task) for all listening conditions. Skin conductance increased significantly with an increase in evaluative threat, but only for the more demanding task. There was no significant change in HRV in response to increasing evaluative threat or task demand.

CONCLUSIONS

Listening effort may be influenced by factors other than task difficulty, as reviewed in Part 1. This idea is supported by the preliminary data indicating that the sympathetic nervous system response to task demand is modulated by social evaluative threat. More work is needed to determine the relative contributions of motivation and emotional stress on physiological responses during listening tasks.

Virtual Reality for Research in Social Neuroscience

The emergence of social neuroscience has significantly advanced our understanding of the relationship that exists between social processes and their neurobiological underpinnings. Social neuroscience research often involves the use of simple and static stimuli lacking many of the potentially important aspects of real world activities and social interactions. Whilst this research has merit, there is a growing interest in the presentation of dynamic stimuli in a manner that allows researchers to assess the integrative processes carried out by perceivers over time. Herein, we discuss the potential of virtual reality for enhancing ecological validity while maintaining experimental control in social neuroscience research. Virtual reality is a technology that allows for the creation of fully interactive, three-dimensional computerized models of social situations that can be fully controlled by the experimenter. Furthermore, the introduction of interactive virtual characters—either driven by a human or by a computer—allows the researcher to test, in a systematic and independent manner, the effects of various social cues. We first introduce key technical features and concepts related to virtual reality. Next, we discuss the potential of this technology for enhancing social neuroscience protocols, drawing on illustrative experiments from the literature.

Trier Social Stress Test in vivo and in virtual reality: Dissociation of response domains

The Trier Social Stress Test (TSST) is considered a reliable paradigm for inducing psychosocial stress. Virtual reality (VR) has successfully been applied to ensure a greater degree of efficiency and standardization in the TSST. Studies using the TSST in VR (VR-TSST) have reported significant stress reactions, with subjective and peripheral physiological reactions comparable to those in response to the in vivo TSST and with lower cortisol reactions. The current study examined whether an additional virtual competitive factor triggers larger stress responses than a standard VR-TSST. Forty-five male participants were randomly assigned to either in vivo TSST, VR-TSST (VR) or VR-TSST with a virtual competitor (VR+). A significant increase of self-reported stress, electrodermal activity, and heart rate indicated a pronounced stress reaction with no differences between groups. For salivary cortisol, however, responder rates differed significantly between groups, with in vivo participants showing overall higher response rates (86%) than participants of both VR groups (VR: 33%, VR+: 47%). In contrast, participants of both VR groups judged the task significantly more challenging than did in vivo TSST participants. In sum, our results indicate successful stress induction in all experimental conditions, and a marked dissociation of salivary cortisol levels on the one hand, and the physiological and psychological stress reactions on the other hand. The competitive scenario did not significantly enhance stress reactions. VR technology may serve as a standardized tool for inducing social stress in experimental settings, but further research is needed to clarify why the stress reaction as assessed by cortisol differs from peripheral and subjective stress reactions in VR.