A new research study conducted by University of Minnesota researchers Justin Munafo, Meg Diedrick, and Thomas A. Stoffregen says that head-mounted virtual reality is unintentionally sexist toward female users. At least, the paper, titled “The virtual reality head-mounted display Oculus Rift induces motion sickness and is sexist in its effects,” says “unintentionally”; the title and abstract alone don’t quite make that clear. Having procured a copy of the actual paper (unfortunately paywalled), we decided to explore the researchers’ assertion and break it down to understand just what’s at play here because my gut reaction was to be suspicious, likely the same as you.

See, I’ve been to a lot of VR demos, and I rarely saw people get sick from demos outside of the rare indie. In fact, I actually just had my sister try VR for about 20 minutes, and like me, she used to get sick from that stupid Kirby’s Air-Ride game — we both suffer from motion sickness. That made me wonder whether the results were more about VR’s first-person perspective, as I know more women than men who have their motion sickness triggered by the perspective, in which case, it’s not VR but the POV.

But now that I’ve read the paper, I have eaten my proverbial hat.

The findings

Let’s get into the findings before we see how my bias could have led me astray if I hadn’t checked it. The basic experiment had 36 participants, split evenly between men and women to explore gender-based motion sickness susceptibility. The reason there’s a difference in how the genders get motion sickness (specifically, that women are more susceptible to it) has to do with body posture and sexual dimorphism. For those who haven’t noticed, there are some physical differences between men and women, which can account for differences in posture. This, in turn, may affect how susceptible they are to motion sickness.

In order to determine how much the subjects were affected by their sitting VR experience with the Oculus Rift, the researchers tested several attributes. For the purpose of our discussion, we’ll focus on “sway,” the horizontal movement people make while they stand. A good way to tell someone is “off” is if his sway increases, so the subjects had their sway measured before and after playing the games. (There were other factors, like a “search” test, too.)

Two games were used for two experiments to sample a variety of VR games and control schemes. In the first experiment, participants were made to play Balancer Rift, a marble-maze running game controlled by moving your head. As you can see from the above image (Fig 1), women did experience motion sickness more than men, but it wasn’t statistically significant.

The second experiment used an old version of a first-person POV game called Affected. Players move through the halls of a haunted mansion with their controller but are free to look around with their headset. Looking at the results of Figure 3, we can see this game made a lot more people sick, but the difference this time was that there was a statistically significant difference between men and women. In fact, the ratio of sick women to men was 2.33:1. That being said, the severity of motion sickness between the two groups was the same, in both experiments.

Although both gamers and non-gamers were tested, there didn’t seem to be any statistical evidence that gaming experience mattered. As we’ve discussed previously with certain cognitive skills, using similar skill sets doesn’t always mean you can draw a 1:1 connection between activities. In fact, motion sickness sets in differently depending on multiple factors, such as being at sea when it’s calm versus during a storm. According to the theory, motion sickness is caused by “instability in control of the body or its segments.” There are other factors involved, but gender is one of them. In short, the research wasn’t just about checking motion sickness between genders but confirming theories of motion sickness that included theories on how gender is a contributing factor, particularly as is relates to posture and sexual dimorphism.

So, confirmation complete, time to move on, right? Wrong.

The journey

Again, we’re not an academic site, so I’m not going to cross-reference all the research’s sources or discuss numerical bias since most of what I read adds up. There are a few discrepancies to note, though. While I mentioned I knew more women who had motion sickness triggered through games, I admittedly have more and closer female than male friends. The researchers themselves started from anecdotal evidence too and may not have noticed their own bias.

All of the games tested seem to be essentially first-person. While I’d admit that the first-person perspective is the one that makes VR feel the most personal, the Oculus Rift ships with Lucky’s Tale, a third-person POV game. Had the researchers used — or even mentioned — the less publicly known HTC Vive, I might understand Lucky’s Tale’s absence from the experiments, but they didn’t. On a test of motion sickness and different controls, Lucky’s Tale‘s absence feels glaring.

I also should note that while the team understandably referenced a lot of its members’ own work, especially Stoffregen‘s, it also used a lot from Frank Koslucher, whom several of the researchers have worked with in the past. That in itself isn’t an issue, but all of them support the theory that posture and sway are the big factors in motion sickness and gender differences, though other researchers have argued that it has to do with apparent female visual perception advantages. While that opposing study certainly has problems, Stoffregen’s team’s research largely sweeps its argument aside; instead of engaging with a counterpoint, it simply focused on determining whether its own theory could be confirmed in VR after having spent enough time with it in meatspace. I suppose at this early stage of consumer-based VR it’s understandable, but it’s also a bit disappointing.

Another sticking point is that scientists already agree that women are more sensitive to motion sickness than men. So the study and its title are a little bit like kicking people in the groin with Converse shoes and saying men are more likely to be injured by Converse than women. While the setting may be new, the outcome was largely expected, so the focus should remain on the domain: “Women get sick in VR more than men.” I’d think looking at the range of the effect would have been a more interesting study than re-affirming its existence.

Affected was a good follow-up choice because it does something a lot of good VR games that didn’t make me sick do: disconnects body movement from perception. When I walk forward in real life, I can still look around. I don’t do a lot of it, but I can. I don’t know if it still does this, but an early version of Obduction I played tied movement to head position, making me and many other players sick, so it included node based warping as well.

However, Affected lacks something very basic: human reference. There are no human hands; you don’t see shoulders if you look too far back or feet when staring at the ground. While I think including a nose can be heavy-handed, EVE: Valkyrie and Time Machine include an entire human being, but more importantly, they take place inside a vehicle. This is another useful strategy, as the nose idea came from the idea that having fixed visual stimuli — such as a dashboard or plane cockpit — anecdotally helps prevent motion sickness.

Had Stoffregen’s team looked at a game that takes place in a vehicle or includes a body the user can look down at, we might be able to better understand how the posture theory holds up vs. visual perception theory in games that are, theoretically, better designed to prevent the issue in the first place. That is, if the other side says visual perception differences between the genders causes a difference in motion sickness susceptibility, but a game that directly tries to address visual perception shows similar gender-dividing results as a game that doesn’t address it, then visual perception differences might not be a factor.

This is key because this study did include two visual perception tests, but one wasn’t formally measured, and the latter’s results didn’t match previous findings, perhaps due to sample size, which is why it feels as if something was missing.

Even more disappointing is the fact that the researchers noted that there are differences in motion sickness between drivers and passengers. With several vehicle-based VR games out there, it would have been interesting for them to have included at least one such game in their study, especially with all their references to motion sickness at sea.

The takeaway

Although I may have some objections with certain parts of the study, it’s far from useless and presents several critical takeaways for the reader, which I’m glad I set aside my bias to see. The first is that motion sickness symptoms can develop up to 12 hours after an experiment. This makes sense, as I remember coming home from the beach as a kid, sitting on the couch, and then hours later suddenly feel the tide’s push and pull for awhile. Just because I didn’t immediately see people feel sick at convention demos doesn’t mean it didn’t happen.

Second, the reason people may get sick faster in VR than, say, via console play, is that VR presents a “closed-loop” visual display, meaning it’s all around you and not something you can simply look away from, like a TV screen. Motion sickness with console games may take 25-30 minutes to kick in, but VR can affect people in 15 minutes or less. The perspective’s power can be immersive, but implemented incorrectly, that same power absolutely breaks immersion as well. I’ve experience bad VR, but because I now mostly know what to look out for, I often forget just how bad it can be.

Third, the researchers do concede the difference may be cognitive and that this should be further researched. Again, thinking back to our Video Game Debate coverage of games and cognitive function and the lack of carry-over in certain tasks, this seems obvious. Just as someone may adapt to a certain kind of sea-sway but feel sick when the motion of the ocean changes, different kinds of VR experiences might not exactly prepare someone for another experience, even if they seem superficially similar. As the authors note, NASA’s struggled with this issue for years, so VR developers have a long, hard road in front of them. Unfortunately for our readers, that means we gamers may not exactly have an edge over non-gamers in this department, but happily, it also means non-gamers can’t excuse themselves from giving VR a shot due to past experience with games and motion sickness.

Finally, knowing that women potentially suffer motion sickness more easily also means that VR enthusiasts should try to have a broad range of potential games on hand. Again, anything in a vehicle is helpful, but especially for Rift owners, Lucky’s Tale may be useful (even if it doesn’t seem to take full advantage of VR).

Future studies building on the idea that this is an issue would be ideal, especially when we note that “sexist” isn’t being used in this paper the way you and I generally mean it. It simply means there’s a gender difference for one side more than the other. It lacks intention or malice or political construction of any sort. As the researchers note, documenting the different effects of VR on the genders can help developers “design changes that eliminate the discriminatory effects.” While I’d hate to think that first-person perspective might need to go away to make VR more accessible, looking into how or whether third-person POV results in motion sickness could be one step toward at least getting a broader perspective on where VR can move forward as an egalitarian and marketable platform.