Why people get motion sickness is still an unsolved mystery. There are two prominent theories. (a) The conflict between information perceived by the senses and motion detected by the vestibular system in the inner ear. When we are on vehicles our inner ear signals us that we are moving but our eyes tell us we are sitting still. (b) Distortion of postural stability. The human body is never totally motionless, but this basic motion to keep us stable is disturbed when we are on vehicles.
But neither theory quite explains some of the peculiarities concerning motion sickness: (a) the difference between reading and not reading in cars; (b) why motion sickness can be treated by focusing the gaze on the horizon or pretending to be the driver; or c) why we normally don’t get motion sickness in spite of being on a rotating planet. In other words, the mystery lies in the particular state of focus/absorption that alleviates motion sickness. It is not any kind of motion that makes one sick.
The true cause of motion sickness is neither motion nor sensory conflict, though these might be its conditions (the cause of the fire is striking a match whereas its condition is the presence of oxygen). Rather, it appears to be the discrepancies between the body perceived (through focus) and experienced. Motion sickness could very well be a chronic disease of bodies inside bodies.
Focusing on the horizon or imagining yourself as the driver enlarges your body to the scale of the car. This alignment of yourself to the body of the moving vehicle prevents motion sickness. But if the passenger’s body inside the vehicle body is too absorbed in being a part of another body ensemble— by reading books, for instance—the discrepancy between this body ensemble and the body ensemble of the vehicle that the passenger is coordinated with is brought to the fore. It is this gap between two body ensembles that appears to cause sickness. The conflict is not between senses but between body ensembles. Such body ensembles that the human body finds oneself in, are all vehicles in an extended sense. Motion sickness arises from the conflict between the multiple vehicles one is a passenger to.
In the case of planet rotation, it is the utter scale of the body that makes it difficult for the gap to foreground. That is to say, in order to induce motion sickness, the gap/conflict between body ensembles should preferably be within a certain scalar threshold linked to the size of the human body so that it is possible to both perceive and rearrange the coordination with ease (with a mere shift of focus). The rotation of the planet, from this perspective, usually remains transcendental to experience (Kant: that we feel the Earth is not moving is an epistemological fallacy we cannot get away with)—but only “usually,” since one can still get motion sickness from the movement of the planet during earthquakes.
A body is not physical machinery that exists as an object, but a mesophysical ensemble activated through absorption. Through a switch of focus, the human body can be separated from the larger body of the vehicle in which it is absorbed. Absorption thus coordinates/un-coordinates bodies—incorporation. Sex is an act of absorptive incorporation with another body. The extreme feeling of jealousy when imagining or seeing someone you love with someone else is a reaction generated by being left out of that body ensemble. It is an out-of-body experience of sorts.
Scalar thresholds for motion sickness probably exist for two related reasons: when the vehicle is much too large than the human body, it is perceived as a non-moving ground (as opposed to a vehicle that moves on that ground); and since motion also increases in scale, it is consequently felt less.
But why does the discrepancy of vehicles cause sickness? Sickness is a condition of not being in one’s body. Influenza enters a body and un-coordinates the existing coordination between bodies—it upsets the given state of absorption. In this, it works like the Brechtian method of alienation, which dissects the given absorption between the audience and the play. An alien is what disturbs a pre-existing body ensemble. An alien is alien to the pre-existing body ensemble. This is well-depicted in the movie Aliens, which shows aliens as parasites who invade our bodies (body snatchers). This also leads to the imagery of the grotesque as being grounded in the un-coordination of familiar body ensembles (disconnection of body limbs, for instance, though not only within one scale but across many).
Nausea induces throwing-up—the expulsion of alien substances, throwing out of a passenger from your vehicle body.
Motion sickness is a problem for phenomenology. Despite all attempts to do away with all presuppositions (“Epochē”) the Husserlian method presupposes that the ground for thought is stable: both in terms of the planet as well as in terms of the body. This presupposition constitutes a primordial form of absorption. It is what conditions the phenomenological epochē: the bracketing out of all presuppositions about the external world in order to solely focus—absorb oneself—on what appears to be the phenomena. The certainty of the vehicle one thinks in is a presupposition that allows all other presuppositions. In other words, people, especially kids, enact phenomenological epochē every time they get absorbed in video games. We also do this when reading books. These are activities that tend to cause motion sickness when riding a car. In other words, phenomenological epochē, which is nothing other than one form of intense absorption, is prone to motion sickness, since it coordinates intently with one body ensemble and un-coordinates the focus from all others that are nonetheless lived within. There should be a phenomenological account of motion sickness conducted under epochē.
Why and how are dancers trained to overcome motion sickness (Vertigo)? Body habituate over time to vehicles so that the movement becomes the ground (sailors become less susceptible to seasickness). This habituation can be distressed by extreme spinning, for instance (or the consumption of alcohol, etc). But why does spinning on your own cause motion sickness? Isn’t oneself the driver of that movement, since it is your own body that spins? The extant theory explains it yet again via sensory conflict: ”When you spin, the fluid in these canals will spin around. If you stop suddenly, your body stops, but the fluid in your ears is still going. You think you’re still spinning, but your eyes are telling you that you’re not spinning.” But although this may explain why we cannot walk straight after spinning—loss of coordination and balance—it does not explain at all the fact that we start getting sick while we are spinning (and hence when the eyes are telling us that we are indeed spinning).
Again, the best explanation seems to be that it is about the coordination/un-coordination of body ensembles. The coupling of the physical body and the planetary body is a matter of habit. Hence, when one changes the movement of the physical body in relation to the ground, the familiar body ensemble collapses and sickness ensues (hence the same kind of nausea can be caused by the ground moving during earthquakes). This explains also why it is possible to overcome nausea from spinning through training: re-habituation.
A done idea: a dance piece that consists solely of training/habituating the ‘dancer’ to read in vehicles. The dancer, therefore, does not need to move—but to be moved. Nevertheless, if the purpose of this exercise is in habituating the body through movement, isn’t this an essential problem for dance? Organize a workshop where participants attempt to overcome motion sickness.
From this standpoint, Michael Fried’s Absorption and Theatricality can be rewritten as a theory of dance. Absorption through sensory focus coordinates bodies mesophysically. According to Fried, the obliviousness that absorption induces is what distinguishes it from theatricality, where the actor is always conscious of the audience’s gaze. But this obliviousness is the same obliviousness attained through phenomenological epochē: it is the forgetting of other body ensembles that are nonetheless lived mesophysically. We tend to forget that we are passengers.