Ah, now here's an interesting idea:
"Intelligence is function of feedback. The more feedback you get, the more intelligent you become. The less feedback you get, the stupider you become."
-Robert Anton Wilson
I've always thought that the lone genius was a romantic myth mostly. People like Giordano Bruno or Sigmund Freud thrived on interaction (although in Bruno's case, he perhaps got a bit too much interaction with the Inquisition!) and controversy. The trick is in interaction that pushes you further instead of dragging you lower. Maybe we need secret societies.