Simulation sickness is a syndrome immersive technology users may face, notably virtual reality, augmented reality, and flight simulators. It is characterized by symptoms such as nausea, dizziness, sweating, and disorientation—most often stemming from the discrepancy between visual input and the body’s sensation of motion. In the modeling, simulation, and training (MS&T) industries, understanding simulation sickness and its mitigation is critical to ensure effective training, mission preparedness, and general safety.
This blog examines causes of simulation sickness, how it impacts military training, and alleviation strategies with a focus on the MS&T industry.
What Is Simulation Sickness?
Simulation sickness, often referred to as motion sickness or VR sickness, occurs when there is any discrepancy in the sensory input. There is a conflicting signal reaching the brain from the visual system and the vestibular system—that regulates balance and spatial orientation. In a virtual world, one’s sense of sight might interpret motion, yet, one’s body remains stationary, or vice versa. Research has shown evidence that women and children are more susceptible to motion sickness. Genetics also plays a role in how prone on is. This clash between what is seen and what is felt can lead to symptoms including:
- Nausea
- Dizziness
- Fatigue
- Sweating
- Headaches
- Disorientation
In virtual or simulated environments, these symptoms can be debilitating as the users depend greatly on their senses to interact with and move around in the simulation.
Causes of Simulation Sickness
The root cause of simulation sickness is sensory conflict. Immersed in a virtual environment, either through a VR headset or a flight simulator, a user’s eyes see motion and changes in orientation; however, the inner ear, which is responsible for balance, does not feel that physical movement. This conflict between the visual and the vestibular systems can be confusing to the brain, leading to symptoms identified above.
Several factors contribute to the severity of simulation sickness:
- Latency and Frame Rate: High latencies or low frame rates in a VR or simulation system can amplify symptoms. If there is no prompt response by the simulated world to a user’s head movements, his or her brain has great difficulty in making sense out of the uncoordinated information, thus causing discomfort.
- Field of View (FOV): A too narrow or too wide field of view may also cause sensory conflict. In the instance of an excessive FOV, it may make the user feel that they are moving quicker than they really are, which can cause motion sickness.
- Unnatural Movement: Any sudden or unnatural movement within a simulation, such as changing direction or speed, predisposes users to simulation sickness, especially in high-intensity, fast-paced combat scenarios or flight simulators where the user has to make rapid movements.
- Level of Immersion: The more immersive the simulation—using, say, full-body tracking, 3D audio, and photorealistic visuals—the more likely users are to experience sensory conflict. The brain expects a high degree of accuracy from an immersive environment, and when things don’t line up, it can make people feel sick.
Simulation Sickness in the MS&T Industry
Knowledge of simulation sickness cannot be stressed enough in the MS&T sector. The modern methods in the field of training largely depend on highly immersive environments for the simulation of real-world situations in a risk-free controlled setting, such as flight simulators, virtual battlefield environments, and tactical simulations where soldiers, pilots, and other personnel are trained in multiple scenarios varying from combat engagement to navigation and mission executions.
The MS&T industry has come far in the pursuit of mitigating this challenge, however, the rigors of military training can sometimes sharpen the effects of simulation sickness. Therefore, training systems should have measures to reduce discomfort while maximizing effectiveness.
Key Aspects of Simulation Sickness in Military Training:
- Long training sessions: most military training takes place either in simulators or under virtual reality for long stretches periods. This will increase the likelihood of simulation sickness due to prolonged exposure to sensory mismatch, especially if users are tasked with high-stakes missions that require quick decision-making.
- Realistic combat and flight simulations: advanced military simulations present users with high-speed turns, rapid directional changes, and other exigencies—all of which have the potential to trigger simulation sickness—especially if the fighter pilot or soldier is tasked with conducting high-speed, high-pressure maneuvers.
- Mental and physical stress: military training is both mentally and physically demanding. In combination with the discomfort associated with simulation sickness, this can notably reduce cognitive performance, hamper decision-making, and have a negative effect on performance.
Combating Simulation Sickness in MS&T
Fortunately, there are several strategies and technologies used in the MS&T industry to fight against simulation sickness, to increase training effectiveness and reduce personal discomfort.
- Improvement of Hardware and Software
- High frame rates and low latency: Advanced simulation systems should have a high frame rate—at least 60 FPS—coupled with low latency, so that the visual feedback matches the movement inputs given by a user. It decreases the possibility of sensory mismatch, a leading cause of simulation sickness.
- Realistic Motion Cues: The more realistic motion cues, such as g-force simulation, tactile feedback, and realistic seat movements in flight simulators, the more it harmonizes the visual and vestibular signals, thereby reducing the possibility of simulation sickness.
- Adaptive Software: Some simulators use adaptive algorithms that adjust the intensity of the virtual environment according to the user’s movements, therefore reducing the possibility of sensory conflict.
- Gradual Exposure and Training
- Desensitization Protocols: Simulation sickness can also be reduced by gradually increasing exposure to the simulation; this “desensitization” helps the user build up tolerance to the simulated environment and get accustomed to the motion cues.
- Frequent Breaks.
- It is also possible to reduce the symptoms of simulation sickness by taking frequent breaks during a training session. The breaks allow the body time to recalibrate and reduce physical and mental strain from the prolonged exposure to the simulation.
- Optimizing Simulation Environments
- Adjustable Field of View (FOV): Allow users to adjust the parameters of FOV; in this way, it offers customization for each individual user. A smaller value of FOV decreases less natural motions and decreases sickness during simulations.
- Natural Patterns of Movement in Virtual Environments: Simulating natural movements of the human body – for example, natural transitions between states of motion – will reduce feelings of discomfort.
- Training Staff in Coping Mechanisms
- Cognitive Strategies: For some trainees, instruction in coping strategies such as controlled breathing and relaxation techniques can help to control symptoms if they start to feel ill during training.
- Physical Conditioning: Exercise in physical conditioning to increase balance and reduce motion sensitivity may also be helpful for some users.
The Need to Treat Simulation Sickness in Military Training
The MS&T industry is of utmost importance in the safety, readiness, and effectiveness of military personnel. With the advance of technology, more complex, immersive simulations are being incorporated into military training curriculums, allowing trainees to engage in realistic, high-stakes training environments. Simulation sickness, if not managed properly, has devastating effects on the outcomes of training by quite literally taking away a huge chunk of the cognitive and physical performance of service members.
Key Takeaways
Simulation sickness is a negative symptom complex brought about by visual disorientation with physical cue mismatch in either virtual reality or flight simulation. The MS&T industry must take steps in dealing with simulation sickness, otherwise, training effectiveness will decrease without performance and safety degradation. Some mitigation strategies are hardware and software improvement, acclimatization to simulated environments, optimization of the virtual environment, and cognitive and physical coping mechanisms.
Eventually, knowledge and treatment of simulation sickness are not an issue of comfort but a necessity for mission success. Military simulations will advance and ensuring that troops can train for long and intense periods without degradation of physical or cognitive function will be one avenue for improving the performance of both individuals and teams on the battlefield.
About AVT Simulation
AVT Simulation. Applied Visual Technology, Inc. has been providing engineering services that developed modeling and simulation expertise for military training since 1998. AVT specializes in making old training systems new again and making new ones for less. The founder has accumulated more than 30 years of military simulation and training expertise in aviation applications. For over 25 years, AVT Simulation has served our Air Force, Army, Navy, and Marine customers with the highest quality service and solutions. Since its inception, AVT’s highly specialized staff of engineers has included some of the top leaders in the simulation industry. With an average of over 20 years of simulation experience, our dedicated team provides specialized solutions for customers with complex problems.
Interested in learning more about the MS&T industry? Check out the AVT Training Center website to learn more about our class offerings.
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