hmmm

I don't really see the significance of this experiment. It seems like they were simply creating an optical illusion, something that often tricks people

We played a game when we were kids, where one would lay on the ground face down, eyes closed, arms stretched in front of them. The other would grab their arms and lift them off the ground to the point where their back was arched but the head hung down. As they slowly lowered your arms, it eventually felt as if you were being lowered even lower than the floor you were laying on. When you would open your eyes you were often still a ways from the floor. Same kind of experiment, but cheaper!