It feels real: physiological responses to a stressful virtual reality environment and its impact on working memory

Abstract

Background: Virtual reality (VR) is increasingly used to study and treat psychiatric disorders. Its fidelity depends in part on the extent to which the VR environment provides a convincing simulation, for example whether a putatively stressful VR situation actually produces a stress response.

Methods: We studied the stress response in 28 healthy men exposed either to a stressor VR elevator (which simulated travelling up the outside of a tall building and culminated in the participant being asked to step off the elevator platform), or to a control elevator. We measured psychological and physiological (salivary cortisol and alpha-amylase, blood pressure, pulse, skin conductance) stress indices. We also measured subsequent performance on the N-back task because acute stress has been reported to impact on working memory.

Results: Compared to participants in the control elevator, those in the external elevator had increases in skin conductance, pulse and subjective stress and anxiety ratings, altered heart rate variability, and a delayed rise in cortisol. N-back performance was unaffected.

Conclusions: A putatively stressful VR elevator produces a physiological as well as a psychological stress response, supporting its use in the investigation and treatment of stress-related disorders, and its potential value as an experimental laboratory stressor.

Keywords: Virtual reality; cortisol; stress.

Figure 1.

Summary of experimental manipulations. (a) Timeline of the experiment. Blue indicates pre- and post-testing periods; red indicates the time period during which participants were in the VR environment; yellow indicates the period in which participants completed the N-back task (outside of the VR environment). (b) Images from the control elevator. The avatar shown is that of the participant, viewed in a mirror (this reflection was only seen in the case of the control elevator). (c) Images from the stress elevator. For details, see text.

Figure 2.

Summary of the main analyses, with key variables in those randomised to the control (open bars) or stress (closed bars) shown as means ± SEMs. Variables showing a group difference are highlighted with bold text (see Table 2 for full statistical details).

Figure 3.

Variation in physiological stress indices across the experimental time course. Changes in (a) cortisol, (b) alpha-amylase, (c) systolic blood pressure, (d) diastolic blood pressure, (e) pulse rate, (f) skin conductance, (g) heart rate variability RMSSD and (h) LF-HF ratio measures over the course of the experiment in those randomised to the control (blue triangles and solid lines) and stress (red squares and dashed lines) elevator. Vertical dashed lines indicate the period that participants were immersed in the VR environment (i.e. from just after time point 3 to just before time point 5).

Figure 4.

Variation in psychological indices across the experimental time course. Changes in VAS ratings of (a) ‘Anxious’, (b) ‘Stressed’, (c) ‘Nausea’ and (d) ‘Alert’ over the course of the experiment in those randomised to the control (blue triangles and solid lines) and stress (red squares and dashed lines) elevator. Note that VAS ratings were not taken at T4 as participants were in the VR. Vertical dashed lines indicate the period that participants were immersed in the VR environment (i.e. from just after time point 3 to just before time point 5).