Doing research on XY

Whenever I go to a conference, talk or lecture and someone says "I'm doing research on XY" I see them before me as actually sitting/standing on that person/thing and doing research on it. It's one of those terrible jokes one never voices, because he has enough self-critique to know that they aren't funny. Nevertheless, I cannot get it out of my head. So here it goes. One I heard a few weeks ago from a philosopher: "I'm doing research on Wittgenstein".