Why Puke?

It really IS your inner ear that makes you feel dizzy when you experience angular accelerations like those felt in the centrifuge. In fact, investigating how the inner ear is affected by motion is a critical aspect of Air Force human factors studies.

 The conflicting data from pilots' eyes, inner ear, and their "seat of the pants feeling" when they are flying in conditions of reduced visibility is probably THE major cause of aircraft mishaps.

 
The conflicting data from one's senses is called SPATIAL DISORIENTATION. It has a variety of causes and some very strange effects. The reason that human susceptibility to spatial disorientation is so high is that we are designed to live on the ground.

 On the ground, down is almost always where your feet are. In an aircraft, however, the place you feel "gravity" pulling you may be only close to down, sideways, or even straight up! This is because a pilot in an aircraft senses not only the acceleration due to the Earth's gravity, but the acceleration of his aircraft as well. The vectorsum of these accelerations is the direction his body and his inner ear thinks is down.

 
Pilots are usually able to maintain their orientation to the real downward direction by concentrating on their instruments. However this is a challenge to their brains, as the symbolic data being presented to their eyes (the attitude displayed on their instruments) conflicts with the data being sensed by their natural balance sensors. In fact, there are times when pilots' brains refuse to believe their eyes and their conscious thoughts, and instead let the inner ear reign supreme. Other times, the accelerations pilots experience are so severe that no matter how hard they try to overcome the sensations, their inner ears become overwhelmed with data and they become very dizzy.