A Sensory Conflict May be What Causes Motion Sickness – Astronauts Help Us Understand Why
What causes motion sickness? The theory of vestibular sensory conflict is to blame, but scientists are also studying astronauts to understand the cause even more.
Key Takeaways on Motion Sickness
Motion sickness is caused by vestibular sensory conflict. This means, there is a difference between incoming vestibular information and what we expect that vestibular information to be.
Symptoms of motion sickness include vomiting, dizziness, or a headache.
You can prevent motion sickness by avoiding vestibular sensory conflict.
Roll down the windows
Avoid reading
Look at the horizon or close your eyes
> Help may come from scientists who are studying the ultimate trip – space travel. Astronauts must also cope with motion sickness, and researchers are hoping to help space exploration by stopping symptoms. People on Earth may also benefit.
Cause of Motion Sickness: Vestibular Sensory Conflict
A 2020 study in Transportation Research found that 59 percent of participants had experienced motion sickness in the past five years. For astronauts, motion sickness is even more common.
“Reports aren’t perfect, but we estimate that serious symptoms of motion sickness, including vomiting, impact around 70 percent of astronauts despite motion sickness medication such as scopolamine,” says Aaron Allred, a postdoctoral research fellow in Aerospace Engineering Sciences at the University of Colorado-Boulder.
So why does motion make so many people sick?
Vestibular sensory conflict is one of the most widely accepted theories.
The car’s driver, in contrast, is looking at the road and processing visual information along with feeling movements. This helps the brain form expectations.
Read More: Why Do Some People Get Motion Sick And Others Don't?
Stopping Motion Sickness with Electric Stimulation
In a 2025 study in Communications Engineering, Allred and his research partners wanted to test vestibular sensory conflict. To do so, they recruited participants who agreed to get motion sick for the sake of science. Three times, the participants went to the researchers’ laboratory where they sat on a sled in the dark. On each occasion, the sled slid from side to side, mimicking the motion a person might feel when a car makes a turn.
“Each time we provided the same exact motion, but in each case, a different electrical stimulation to the vestibular system was provided,” Allred says.
- Some of the electrical stimulation was intended to help mediate motion sickness. But some were meant to make it worse.
“So a lot of credit goes to our participants!” Allred says.
The study found that the electrical stimulation meant to help reduce motion sickness indeed reduced it by a reported 26 percent. The electrical stimulation intended to worsen motion sickness had the desired effect, and participants reported a 56 percent increase in symptoms. Electrical stimulation to reduce motion sickness is not yet available to the public. So, people trying to prevent motion sickness need to avoid vestibular sensory conflict.
“Looking at fixed elements in the cabin, like reading a book, is probably the worst thing you can do since it gives you a false expectation of what your vestibular system will sense during the transit, so if windows aren’t an option, it may be better to keep your eyes closed,” Allred says.
Motion Sickness, or Something Else
- If vestibular sensory conflict is avoided, motion sickness should be stopped. If dizziness continues long after the car is put in park, a person may need to consult with a physician.
- Motion sickness can also share symptoms with other conditions related to cardiovascular, neurological, metabolic, psychiatric, or vestibular issues.
People with conditions like persistent postural-perceptual dizziness or vestibular migraine may be more susceptible to motion sickness.
- And because their symptoms are similar to motion sickness, it can be difficult for physicians to diagnose.
Relief may come in the future as scientists working to tackle motion sickness in space share their findings with those on Earth.
This article is not offering medical advice and should be used for informational purposes only.
Read More: As if Space Travel Wasn't Enough, Astronauts Also Experience Headaches in Orbit
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Transportation Research. An international survey on the incidence and modulating factors of carsickness
Communications Engineering. Validating sensory conflict theory and mitigating motion sickness in humans with galvanic vestibular stimulation
American Journal of Otolaryngology. Visual vertigo and motion sickness is different between persistent postural-perceptual dizziness and vestibular migraine
Emilie Lucchesi has written for some of the country's largest newspapers, including The New York Times, Chicago Tribune and Los Angeles Times.
She holds a bachelor's degree in journalism from the University of Missouri and an MA from DePaul University. She also holds a Ph.D. in communication from the University of Illinois-Chicago with an emphasis on media framing, message construction and stigma communication.
Emilie has authored three nonfiction books.
Her third, A Light in the Dark: Surviving More Than Ted Bundy, releases October 3, 2023, from Chicago Review Press and is co-authored with survivor Kathy Kleiner Rubin.
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