Jennifer Long: I really enjoyed your workshop on motion sickness at the International Ergonomics Association IEA2021 congress in June. Thanks for agreeing to be interviewed for this blog. Can you please briefly explain what is motion sickness?

Joseph Smyth: Motion sickness is a state of unwellness that occurs in environments where motion (or perceived motion) is present. It is a catch-all term which covers environment-specific states such as ‘car sickness’ ‘sea sickness’, ‘air sickness’ and ‘simulator sickness’.

JL: Why do people experience motion sickness while reading in a car, but not while driving?

JS: It occurs when your body receives conflicting motion cues. For example, if you are reading a book whilst traveling as a passenger in a car, your eyes will tell your brain you are staying still – this is because the visual environment while you are reading is ‘static’. However, your vestibular system (the ‘balance organs’ within your inner ear) will feel the motion of the vehicle as you move along the road. This conflict in senses (e.g., sensory conflict) is responsible for causing motion sickness.

JL: I was stunned to hear that 60% of people experience car sickness and that 30% of people are severely affected by it. Why do you think we don’t hear more about motion sickness?

JS: Humans have documented motion sickness as early as 800 BC ¹. It seems people have generally accepted that it is an issue and there has been little motivation to tackle it. People who experience motion sickness can also fairly easily adopt strategies to help them avoid symptoms, for example:
•    The overwhelming majority of train commuters will choose to sit forward-facing on a train.
•    Travelers will find a seat at the front of a bus/coach.
•    In the UK people will take the Eurostar rather than the channel ferry.
•    People will drive the family vehicle rather than being a passenger.
•    Or if they are a passenger, they won’t read books or play on their phone, but instead just watch the road ahead to avoid sensory conflict.

JL: It seems that many people are very excited about the prospect of self-driving cars (automated vehicles). It will give us the opportunity to catch up on work tasks, read books, or watch movies while traveling. Do you think that people might be disappointed that motion sickness prevents them from doing these activities in self-driving cars?

JS: We know that automated vehicles (AV) are far more likely to induce motion sickness than traditional vehicles. There are a few reasons for this:
•    The lack of controllability is a known influencer in motion sickness – not being able to drive makes everyone a ‘passenger’ and this is where motion sickness occurs.
•    Many AV concept designs show small windows, rearward facing seats and display screens scattered throughout the cabin. The design of the vehicle will have a significant influence on motion sickness. It’s important manufacturers recognise this to ensure their vehicles are conducive to a comfortable experience for their users.
•    Eyes-off road tasks such as reading are known to induce motion sickness for many people, as I described earlier. Very few people today could work from a laptop whilst a passenger in a car without feeling a bit queasy – and this remains true for AV’s. The only task known to help avoid motion sickness is to look out of the windscreen at the road ahead – but people do not want to do this in an AV for they feel they may as well be driving it themselves.

Unless we address motion sickness in the design of these new vehicles, then it is possible that people will be disappointed.

JL: During the workshop there was quite a lengthy discussion about the safety implications of motion sickness in automated vehicles. Can you please briefly explain this to our readers?

JS: ‘Autonomous vehicles’ is the term we use for fully-automated vehicles (that is, no steering wheel). But motion sickness is also a challenge for partially, conditionally and highly automated vehicles where the car can complete aspects of the driving task under some conditions. In such a case, the car could be ‘driving itself’ whilst the occupant is engaging in other, more exciting activities.

The problem arises if a person is motion sick and then needs to regain control of the vehicle. My previous research highlighted how motion sickness negatively affects human performance in many areas (including reaction time). We would not give back control of a moving vehicle to someone we know to be over the drink-drive limit. But would we give control to someone who is heavily motion sick? Worse still – recommended handover times for conditionally automated vehicles is about 10 seconds, but motion sickness recovery takes an average of 45 minutes.

JL: You have given considerable thought for how to reduce the risk of motion sickness in self-driving cars. What is your advice?

JS: I think that there are five distinct areas to consider for managing motion sickness in AVs. These are:
•    Occupant characteristics, such as a person’s susceptibility to motion sickness, and the type of clothes they are wearing.
•    Interior design of the vehicle, such as seating and windows.
•    Vehicle design, such as size, height, vehicle dynamics and suspension.
•    Activities undertaken within the vehicle, such as reading, working.
•    The driving style, speed and route of the automated driving system.
If readers are interested, there is more detail in this publication²:

JL: In the world of ergonomics and safety, we usually recommend that it is better to design-out a problem, rather than “blame the worker”. But you have discovered that brain training puzzles can help reduce a person’s susceptibility to motion sickness. Should we all be doing brain training puzzles?

JS: I have pioneered research into the personal mitigation of motion sickness through developing ‘brain training’ puzzles, such as being able to mentally rotate an image of a three-dimensional object. These types of activities seem to be highly effective in reducing a person’s susceptibility to motion sickness. We recently had a paper published about this in Applied Ergonomics³.

It is still early days in this area of research, but it is certainly showing some promise. Our initial experiments show a reduction in motion sickness by over 50%.

JL: Why do you think it is important for us to solve motion sickness?

JS: Motion sickness occurs in a variety of domains. It stops Navy staff performing at peak capacity at sea, it limits employability for air stewards, it affects pilot training in flight simulators and it plagues astronauts in training (simulation sickness) and in space (space sickness). Some people are unable to use VR headsets altogether, where some can only use them for short periods and when the depicted scene requires no ‘self’ movement (e.g., the viewpoint of the user never moves).

Technologies such as VR are incredibly exciting and have the potential to revolutionise many industries, training regimes and job roles – but only if we can tackle motion sickness, fully.

JL: Women are more susceptible to motion sickness. Do you think this will this have implications for their use of newer technology and for their employability?

JS: Yes, women are about twice as susceptible to motion sickness compared to men. The implications of this are challenging. It may be a reason why it is difficult to recruit women to sea-going navy roles. It may limit job opportunities for aspiring female pilots – where simulator training plays a huge role. And it makes the many productivity benefits of automated vehicles non-uniformly accessible throughout the population. In short, the full benefits of automated vehicles may not be accessible to all unless we tackle the issue of motion sickness.

JL: Thank you very much, Joseph, for sharing your thoughts and research about motion sickness. Good luck with your research, and I look forward to hearing more about this in years to come.

JS: Thank you.

Jennifer Long is a visual ergonomics consultant in Sydney, Australia. www.visualergonomics.com.au

Joseph Smyth is a research fellow within the Intelligent Vehicles group at WMG in the National Automotive Innovation Centre, University of Warwick. He is interested in all aspects of human interaction with vehicle technology including automated vehicles, electric vehicles, human-machine-interface design and driver state monitoring. He conducts a lot of research using driving simulators and looks to ensure future technology is both safe and pleasurable to use.
https://warwick.ac.uk/fac/sci/wmg/research/cav/humanfactors/people

Photo by Ondrej Bocek on Unsplash
 

References

1.    Huppert D, Benson J, Brandt T (2017) A historical view of motion sickness – A plague at sea and on land, also with military impact. Frontiers in Neurology 8: article 114  https://www.frontiersin.org/articles/10.3389/fneur.2017.00114/full

2.    Smyth J, Jennings P, Birrell S. Are you sitting comfortably? How current self-driving car concepts overlook motion sickness, and the impact it has on comfort and productivity. Advances in Human Factors of Transportation, Proceedings of the AHFE 2019 International Conference on Human Factors in Transportation, July 24-28, 2019, Washington D.C., USA https://link.springer.com/chapter/10.1007/978-3-030-20503-4_36

3.    Smyth J, Jennings P, Bennet P, Birrell S (2021) A novel method for reducing motion sickness susceptibility through training visuospatial ability – A two-art study. Applied Ergonomics 90: 103264. https://www.sciencedirect.com/science/article/pii/S000368702030212X?via%3Dihub