When I was learning to draw, one technique to help spot errors is to flip the drawing upside down. This made misaligned features, bad proportions, weird perspective issues immediately jump out.
It sounds like the 'prism-goggles' from the article's experiment control for the effect of just looking at it upside down. Clearly what's needed is to hang some students by their feet and send some others to space to see if it's the inner-ear effects or the posture that changes your perception :P
Art teachers also have people copy existing art upside down, or turn their still life upside down (if possible). By trying to reproduce something upside down, your brain doesn't do as much pre-processing and chunking into preconceived shapes, and you're forced to actually look at the shape of the thing.
