I think when the professor said, "study," he meant, "excuse for me to show you that you are basically a lousy person and don't know it." It was a lie, IOW.

I also thought evil guard (and maybe Horshack) was a plant. Only then nothing happened.

The only thing I can think that might make it come back someday is that Creepy RA mentioned that the experiment changed his life, and then he trailed off creepily, as he has a way of doing.