Researchers found that adding synchronized scents to immersive virtual nature experiences improved short-term mood in U.S. Navy personnel, although larger studies are needed to determine whether these benefits can be sustained in isolated and confined operational environments.
Study: The scent of serenity: lessons learned from olfactory-enhanced virtual reality for stress reduction in isolated and confined environments. Image credit: Gorodenkoff/Shutterstock.com
A recent Frontiers in Psychology study evaluated the immediate and longer-term effects of olfactory-enhanced virtual reality (VR) on mood, perceived stress, and cognitive performance in an isolated operational environment, exploring whether it could serve as a practical behavioral health tool.
Can virtual nature offset the effects of isolation?
Chronic stress has significant adverse effects on psychological and behavioral health, particularly in isolated, confined, and extreme (ICE) environments, such as those encountered by astronauts and military personnel. ICE environments introduce additional stressors, including isolation, monotony, and unpredictability, that exacerbate psychological deterioration and cognitive decline. Sensory deprivation and monotony further elevate the risk of negative behavioral health outcomes, especially where sustained cognitive performance is critical.
Naval personnel, in particular, face environmental challenges that disrupt circadian rhythms and hinder restorative processes, thereby elevating psychological strain. The prevalence of severe stress within this group highlights the critical need for scalable, targeted interventions in austere operational settings.
Natural environments are well known to support psychological well-being and help restore mental resources. However, access to these environments is inherently limited in ICE settings. VR offers a portable way to recreate natural environments and has been shown to reduce stress and anxiety across a range of settings, including ICE environments. Most current VR interventions rely on visual and auditory experiences, but incorporating additional senses, such as smell, may further enhance immersion and psychological benefits.
Olfactory stimuli are largely absent from VR applications due to technical barriers in odor delivery. Given the olfactory system’s direct connection to emotional regulation and cognitive function, integrating scent could substantially enhance VR-based interventions. Critically, the long-term and cognitive benefits of olfactory-enhanced VR in ICE environments remain insufficiently investigated.
Researchers tested scent-enhanced VR aboard a warship
The current study used a parallel-group design to investigate the psychological and cognitive effects of repeated VR exposure to nature, with or without olfactory augmentation, over two weeks. Twenty-nine active-duty U.S. Navy personnel, aged 18–64 years, all in good health with a functional sense of smell, were recruited. They boarded a warship and completed a pre-screening questionnaire. Participants were randomly assigned to one of three groups: control (no VR), audiovisual VR, or olfactory-enhanced VR (OVR), using block randomization. Six participants did not complete the full study because of operational demands.
The VR and OVR groups each completed four immersive nature sessions, each lasting about 30 minutes, including approximately 15 minutes of VR exposure, with post-session surveys and feedback. Participants could freely select and explore different virtual environments during sessions. All sessions took place in a designated space, supervised by a trained research assistant who ensured proper use of equipment and participant safety.
VR was delivered via HTC Vive Pro Eye headsets with controllers for navigation, adaptive 3D audio, and, for the OVR group, pulsed scents synchronized with the virtual environment for enhanced multisensory immersion.
The protocol included a familiarization session, followed by three assessment points: baseline (T1), mid-point (T2), and end-point (T3). Participants completed cognitive tests and surveys during familiarization and baseline; cognition and mood were reassessed at T2 and T3, and an exit survey was administered at T3. The control group received no intervention.
Long-term mood and cognition remained largely unchanged
The researchers found that emotional responses changed little after the VR sessions, with one notable exception: participants who experienced olfactory-enhanced VR reported a significant reduction in negative feelings immediately after the intervention. In contrast, positive emotions remained unchanged in both the standard VR and olfactory-enhanced VR groups.
Both VR experiences were generally perceived as restorative, but neither produced a stronger sense of presence or immersion than the other. Participants in both groups remained relatively aware of their real-world surroundings while using the headset, although those in the standard VR group reported slightly higher general and spatial presence. Despite these differences, none of the presence or restorativeness measures differed significantly between the two groups.
When the researchers examined changes over the full two-week study period, they found that mood and perceived stress remained stable across all groups. However, participants with higher resilience consistently reported lower levels of negative emotion and perceived stress, regardless of whether they received the VR intervention.
Cognitive performance also remained largely unchanged over time, with no clear evidence that either VR intervention improved thinking speed or accuracy. Higher resilience was associated with better performance on a small number of cognitive tasks, while modest declines were observed in measures of emotion recognition, vigilance, and risk-taking. The researchers noted that these changes were small, inconsistent across tests, and should be interpreted cautiously.
Participants described the VR intervention as relaxing and enjoyable, with most willing to use it again. The forest was the favorite environment. In the OVR group, scents were seen as a positive and memorable addition, with participants describing them as pleasant, memory-evoking, and capable of triggering personal memories. Feedback emphasized that immersive, multisensory features increased engagement.
Multisensory VR could support mental health in isolation
Olfactory-enhanced VR may be a short-term tool for reducing negative mood, although the findings remain preliminary. Although immediate affective benefits were observed, the study found no evidence of sustained psychological or cognitive benefits under the exposure conditions tested, and the long-term psychological and cognitive impacts remain unclear.
Further research should investigate whether repeated or prolonged use can yield sustained effects and explore the underlying mechanisms that drive these improvements. As multisensory VR technology becomes more accessible, it may offer an important supplement to traditional mental health interventions, particularly for individuals without regular access to natural environments.
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